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

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.

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.

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.

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.

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.

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.

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.

Single electron relativistic clock interferometer

NASA Astrophysics Data System (ADS)

Bushev, P. A.; Cole, J. H.; Sholokhov, D.; Kukharchyk, N.; Zych, M.

2016-09-01

Although time is one of the fundamental notions in physics, it does not have a unique description. In quantum theory time is a parameter ordering the succession of the probability amplitudes of a quantum system, while according to relativity theory each system experiences in general a different proper time, depending on the system's world line, due to time dilation. It is therefore of fundamental interest to test the notion of time in the regime where both quantum and relativistic effects play a role, for example, when different amplitudes of a single quantum clock experience different magnitudes of time dilation. Here we propose a realization of such an experiment with a single electron in a Penning trap. The clock can be implemented in the electronic spin precession and its time dilation then depends on the radial (cyclotron) state of the electron. We show that coherent manipulation and detection of the electron can be achieved already with present day technology. A single electron in a Penning trap is a technologically ready platform where the notion of time can be probed in a hitherto untested regime, where it requires a relativistic as well as quantum description.

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

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.

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.

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

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.

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.

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

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.

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

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.

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

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.

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.

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.

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.

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.

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.

The length of pre-existing fissures effects on the mechanical properties of cracked red sandstone and strength design in engineering.

PubMed

Wu, Jiangyu; Feng, Meimei; Yu, Bangyong; Han, Guansheng

2018-01-01

It is important to study the mechanical properties of cracked rock to understand the engineering behavior of cracked rock mass. Consequently, the influence of the length of pre-existing fissures on the strength, deformation, acoustic emission (AE) and failure characteristics of cracked rock specimen was analyzed, and the optimal selection of strength parameter in engineering design was discussed. The results show that the strength parameters (stress of dilatancy onset and uniaxial compressive strength) and deformation parameters (axial strain and circumferential strain at dilatancy onset and peak point) of cracked rock specimen decrease with the increase of the number of pre-existing fissures, and the relations which can use the negative exponential function to fit. Compared with the intact rock specimens, the different degrees of stress drop phenomena were produced in the process of cracked rock specimens when the stress exceeds the dilatancy onset. At this moment, the cracked rock specimens with the existence of stress drop are not instantaneous failure, but the circumferential strain, volumetric strain and AE signals increase burstingly. And the yield platform was presented in the cracked rock specimen with the length of pre-existing fissure more than 23mm, the yield failure was gradually conducted around the inner tip of pre-existing fissure, the development of original fissures and new cracks was evolved fully in rock. However, the time of dilatancy onset is always ahead of the the time of that point with the existence of stress drop. It indicates that the stress of dilatancy onset can be as the parameter of strength design in rock engineering, which can effectively prevent the large deformation of rock. Copyright © 2017 Elsevier B.V. All rights reserved.

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?

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.

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.

The narcoleptic cognitive pupillary response.

PubMed

O'Neill, W D; Trick, K P

2001-09-01

It has been reported that narcoleptics exhibit deficits in short-term memory, list recall, and stimulus frequency estimation compared with control subjects. It is also well-known that pupil dilation during cognitive tasks is a measure of subject attention state. Here we present results from six narcoleptics and six controls, a total of 360 experimental records in which pupillograms were made during cognitive tests, which indicate that narcoleptics begin pupillary dilations at a smaller diameter, begin dilating earlier poststimulus, attain higher pupillary diameter velocities, yet achieve the same equilibrium dilation diameter as controls. These findings are derived from statistical tests performed on the parameters of a nonlinear regression model of pupillary cognitive dilation as a function of time. In our experiments, the standard 1-s interdigit time between cognitive stimuli was increased to 2.3 s, which yielded pupillographic time records showing that the process of short-term memory overload sets in gradually at about four memory digits for controls and three memory digits for narcoleptics. We suggest our results can be partially explained by a narcoleptic stimulus-encoding deficit, which limits the time available for subjects to rehearse cognitive tasks. However, we also report the unexpected finding that the inferred encoding deficit is a transient one in that repeated tasks at the same memory load elicit a near normal naroleptic pupillary dilation.

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.

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.

[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.

Echocardiographic evaluation of diastolic parameters in dogs with dilated cardiomyopathy.

PubMed

Garncarz, M A

2007-01-01

Echocardiography is a valuable tool for the evaluation of systolic and diastolic cardiac function. A high correlation between measurements of diastolic mitral inflow parameters analyzed with Doppler echocardiography and invasive methods makes the former valuable. The aim of this study was to ascertain if significant differences occur in diastolic myocardial parameters between dogs with no heart disease and dogs with subclinical or clinical dilated cardiomyopathy. Furthermore the aim of the study was to determine whether heart failure in dilated cardiomypathy is a result of systolic dysfunction alone or both systolic and diastolic dysfunction. Eleven parameters were analyzed: E wave, E-AT, E-DT, E time, A wave, A-AT, A-DT, A time, E+A time, E/A ratio, and IVRT. The study confirmed the value of noninvasive echocardiographic assessment of diastolic function in dogs with dilated cardiomyopathy. Significant differences were found in E wave, E-AT, E time, E/A ratio and IVRT between healthy dogs and dogs with dilated cardiomyopathy. All are characterized by a significant decrease compared to healthy dogs after taking into account age and body weight except for the E/A ratio, which significantly increased in value. There were no significant changes in any of the Doppler parameters for diastolic evaluation in subclinical cases of DCM. Advanced heart failure in dilated cardiomyopathy entails systolic and diastolic dysfunction.

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

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.

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.

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.

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).

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.

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.

[Transurethral thulium laser urethrotomy for urethral stricture].

PubMed

Liu, Chun-Lai; Zhang, Xi-Ling; Liu, Yi-Li; Wang, Ping

2011-09-01

To evaluate the effect of endourethrotomy with thulium laser as a minimally invasive treatment for urethral stricture. We treated 36 cases of urethral stricture or atresia by endourethrotomy with thulium laser, restored the urethral continuity by vaporization excision of the scar tissue, and observed the clinical effects and complications. The mean operation time was 35 min, ranging from 10 to 90 min. Smooth urination was achieved after 2-6 weeks of catheter indwelling, with no urinary incontinence. The patients were followed up for 4-24 (mean 12) months, during which 27 did not need any reintervention, 5 developed urinary thinning but cured by urethral dilation, 3 received another laser urethrotomy for previous negligence of timely urethral dilation, and the other 1 underwent open urethroplasty. Thulium laser urethrotomy is a safe and effective minimally invasive option for short urethral stricture, which is also suitable for severe urethral stricture and urethral atresia. Its short-term outcome is satisfactory, but its long-term effect remains to be further observed.

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.

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.

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.

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.

Tests of general relativity using pulsars

NASA Technical Reports Server (NTRS)

Reichley, P. E.

1971-01-01

The arrival times of the pulses from each pulsar are measured by a cesium clock. The observations are all made at a frequency of 2388 MHz (12.5 cm wavelength) on a 26 m dish antenna. The effect of interstellar charged particles is a random one that increases the noise level on the arrival time measurements. The variation in clock rate is shown consisting of two effects: the time dilation effect of special relativity and the red shift effect of general relativity.

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

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.

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.

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

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

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

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.

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.

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.

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.

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.

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.

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)

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.

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.

Moving Clocks Do Not Always Appear to Slow down: Don't Neglect the Doppler Effect

ERIC Educational Resources Information Center

Wang, Frank

2013-01-01

In popular accounts of the time dilation effect in Einstein's special relativity, one often encounters the statement that moving clocks run slow. For instance, in the acclaimed PBS program "NOVA," Professor Brian Greene says, "[I]f I walk toward that guy... he'll perceive my watch ticking slower." Also in his earlier piece for The New York Times,…

[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.

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.

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.

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.

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

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.

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.

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.

Pravastatin and endothelium dependent vasomotion after coronary angioplasty: the PREFACE trial

PubMed Central

Mulder, H; Schalij, M; Kauer, B; Visser, R; van Dijkman, P R M; Jukema, J; Zwinderman, A; Bruschke, A

2001-01-01

OBJECTIVE—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.
DESIGN—A double blind, randomised, placebo controlled, multicentre study.
SETTING—Four hospitals in the Netherlands.
PATIENTS—63 non-smoking, non-hypercholesterolaemic patients scheduled for elective balloon angioplasty (pravastatin 34, placebo 29).
INTERVENTIONS—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.
MAIN OUTCOME MEASURES—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.
RESULTS—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).
CONCLUSIONS—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.


Keywords: angioplasty; endothelium; acetylcholine; pravastatin PMID:11602546

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.

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.

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.

Damping of drop oscillations by surfactants and surface viscosity

NASA Technical Reports Server (NTRS)

Rush, Brian M.; Nadim, Ali

1999-01-01

An energy equation is derived for the general case of a viscous drop suspended in a viscous medium with surfactants contaminating the interface. It contains terms that clearly identify dissipation contributions from the viscous effects in the bulk fluids, surface shear and dilatational viscosity effects at the interface, and surfactant transport. An efficient boundary integral method is developed which incorporates the effects of a constant surface dilatational viscosity in simulations of an oscillating two-dimensional inviscid drop. Surface dilatational viscosity is shown to have a significant damping effect on the otherwise undamped inviscid oscillations.

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.

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.

Relativistic Velocity Addition Law from Machine Gun Analogy

ERIC Educational Resources Information Center

Rothenstein, Bernhard; Popescu, Stefan

2009-01-01

Many derivations of the relativistic addition law of parallel velocities without use of the Lorentz transformations (LT) are known. Some of them are based on thought experiments that require knowledge of the time dilation and the length contraction effects. Other derivations involve the Doppler effect in the optic domain considered from three…

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.

Pore Pressure Evolution in Shallow Subduction Earthquake Sequences and Effects on Aseismic Slip Transients -- Numerical Modeling With Rate and State Friction

NASA Astrophysics Data System (ADS)

Liu, Y.; Rice, J. R.

2005-12-01

In 3D modeling of long tectonic loading and earthquake sequences on a shallow subduction fault [Liu and Rice, 2005], with depth-variable rate and state friction properties, we found that aseismic transient slip episodes emerge spontaneously with only a simplified representation of effects of metamorphic fluid release. That involved assumption of a constant in time but uniformly low effective normal stress in the downdip region. As suggested by observations in several major subduction zones [Obara, 2002; Rogers and Dragert, 2003; Kodaira et al, 2004], the presence of fluids, possibly released from dehydration reactions beneath the seismogenic zone, and their pressurization within the fault zone may play an important role in causing aseismic transients and associated non-volcanic tremors. To investigate the effects of fluids in the subduction zone, particularly on the generation of aseismic transients and their various features, we develop a more complete physical description of the pore pressure evolution (specifically, pore pressure increase due to supply from dehydration reactions and shear heating, decrease due to transport and dilatancy during slip), and incorporate that into the rate and state based 3D modeling. We first incorporated two important factors, dilatancy and shear heating, following Segall and Rice [1995, 2004] and Taylor [1998]. In the 2D simulations (slip varies with depth only), a dilatancy-stabilizing effect is seen which slows down the seismic rupture front and can prevent rapid slip from extending all the way to the trench, similarly to Taylor [1998]. Shear heating increases the pore pressure, and results in faster coseismic rupture propagation and larger final slips. In the 3D simulations, dilatancy also stabilizes the along-strike rupture propagation of both seismic and aseismic slips. That is, aseismic slip transients migrate along the strike faster with a shorter Tp (the characteristic time for pore pressure in the fault core to re-equilibrate with that of its surroundings). This is consistent with our previous simulations, which show that the aseismic transients migrate along the strike at a higher speed under a lower, constant in time, effective normal stress. As a combination of the two factors, we show the pore pressure evolution with drops (due to dilatancy during slip) and then rises (due to shear heating) on the fault over multiple time scales. We next plan to formulate, and merge with the slip-rupture analysis, fuller fluid release models based on phase equilibria and models of transport in which the average fault-parallel permeability is a decreasing function of the effective normal stress. The thrust fault zone, at seismogenic depths and slightly downdip, is represented in a conceptually similar manner to the well-studied major continental faults, assuming the fault core materials have a lower permeability than the neighboring damaged zone. Heat diffusion in the fault core and damaged zone will also be considered in the modeling. The simulation results may help to improve our understanding of the processes of the aseismic transients observed within a transform plate boundary along the SAF near Cholame, California [Nadeau and Dolenc, 2005].

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.

The impact law of confining pressure and plastic parameter on Dilatancy of rock

NASA Astrophysics Data System (ADS)

Wang, Bin; Zhang, Zhenjie; Zhu, Jiebing

2017-08-01

Based on cyclic loading-unloading triaxle test of marble, the double parameter dilation angle model is established considering confining pressure effect and plastic parameter. Research shows that not only the strength but also the militancy behavior is highly depended on its confining pressure and plastic parameter during process of failure. Dilation angle evolution law shows obvious nonlinear characteristic almost with a rapid increase to the peak and then decrease gradually with plastic increasing, and the peak dilation angle value is inversely proportional with confining pressure. The proposed double parameter nonlinear dilation angle model can be used to well describe the Dilatancy of rock, which helps to understand the failure mechanism of surrounding rock mass and predict the range of plastic zone.

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

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.

Poromechanics of stick-slip frictional sliding and strength recovery on tectonic faults

DOE PAGES

Scuderi, Marco M.; Carpenter, Brett M.; Johnson, Paul A.; ...

2015-10-22

Pore fluids influence many aspects of tectonic faulting including frictional strength aseismic creep and effective stress during the seismic cycle. But, the role of pore fluid pressure during earthquake nucleation and dynamic rupture remains poorly understood. Here we report on the evolution of pore fluid pressure and porosity during laboratory stick-slip events as an analog for the seismic cycle. We sheared layers of simulated fault gouge consisting of glass beads in a double-direct shear configuration under true triaxial stresses using drained and undrained fluid conditions and effective normal stress of 5–10 MPa. Shear stress was applied via a constant displacementmore » rate, which we varied in velocity step tests from 0.1 to 30 µm/s. Here, we observe net pore pressure increases, or compaction, during dynamic failure and pore pressure decreases, or dilation, during the interseismic period, depending on fluid boundary conditions. In some cases, a brief period of dilation is attendant with the onset of dynamic stick slip. Our data show that time-dependent strengthening and dynamic stress drop increase with effective normal stress and vary with fluid conditions. For undrained conditions, dilation and preseismic slip are directly related to pore fluid depressurization; they increase with effective normal stress and recurrence time. Microstructural observations confirm the role of water-activated contact growth and shear-driven elastoplastic processes at grain junctions. These results indicate that physicochemical processes acting at grain junctions together with fluid pressure changes dictate stick-slip stress drop and interseismic creep rates and thus play a key role in earthquake nucleation and rupture propagation.« less

Dilatancy and compaction effects on the submerged granular column collapse

NASA Astrophysics Data System (ADS)

Wang, Chun; Wang, Yongqi; Peng, Chong; Meng, Xiannan

2017-10-01

The effects of dilatancy on the collapse dynamics of granular materials in air or in a liquid are studied experimentally and numerically. Experiments show that dilatancy has a critical effect on the collapse of granular columns in the presence of an ambient fluid. Two regimes of the collapse, one being quick and the other being slow, are observed from the experiments and the underlying reasons are analyzed. A two-fluid smoothed particle hydrodynamics model, based on the granular-fluid mixture theory and the critical state theory, is employed to investigate the complex interactions between the solid particles and the ambient water. It is found that dilatancy, resulting in large effective stress and large frictional coefficient between solid particles, helps form the slow regime. Small permeability, representing large inter-phase drag force, also retards the collapse significantly. The proposed numerical model is capable of reproducing these effects qualitatively.

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.

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.

Measurement-induced-nonlocality for Dirac particles in Garfinkle-Horowitz-Strominger dilation space-time

NASA Astrophysics Data System (ADS)

He, Juan; Xu, Shuai; Ye, Liu

2016-05-01

We investigate the quantum correlation via measurement-induced-nonlocality (MIN) for Dirac particles in Garfinkle-Horowitz-Strominger (GHS) dilation space-time. It is shown that the physical accessible quantum correlation decreases as the dilation parameter increases monotonically. Unlike the case of scalar fields, the physical accessible correlation is not zero when the Hawking temperature is infinite owing to the Pauli exclusion principle and the differences between Fermi-Dirac and Bose-Einstein statistics. Meanwhile, the boundary of MIN related to Bell-violation is derived, which indicates that MIN is more general than quantum nonlocality captured by the violation of Bell-inequality. As a by-product, a tenable quantitative relation about MIN redistribution is obtained whatever the dilation parameter is. In addition, it is worth emphasizing that the underlying reason why the physical accessible correlation and mutual information decrease is that they are redistributed to the physical inaccessible regions.

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.

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.

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.

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.

The Effects of Accelerator Frequency and Electron Beam Focusing in Free Electron Lasers

DTIC Science & Technology

2012-12-01

relative to one another. This freezing effect is a result of relativistic time dilation; in the lab frame, the relativistic electron bunch has a slower...average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed...is five months old at the time of this writing, and his smiles and hugs were a much needed treat when I returned home after long days of classes

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.

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.

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.

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.

The inverse problem of estimating the gravitational time dilation

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

Gusev, A. V., E-mail: avg@sai.msu.ru; Litvinov, D. A.; Rudenko, V. N.

2016-11-15

Precise testing of the gravitational time dilation effect suggests comparing the clocks at points with different gravitational potentials. Such a configuration arises when radio frequency standards are installed at orbital and ground stations. The ground-based standard is accessible directly, while the spaceborne one is accessible only via the electromagnetic signal exchange. Reconstructing the current frequency of the spaceborne standard is an ill-posed inverse problem whose solution depends significantly on the characteristics of the stochastic electromagnetic background. The solution for Gaussian noise is known, but the nature of the standards themselves is associated with nonstationary fluctuations of a wide class ofmore » distributions. A solution is proposed for a background of flicker fluctuations with a spectrum (1/f){sup γ}, where 1 < γ < 3, and stationary increments. The results include formulas for the error in reconstructing the frequency of the spaceborne standard and numerical estimates for the accuracy of measuring the relativistic redshift effect.« less

Suppression of slip and rupture velocity increased by thermal pressurization: Effect of dilatancy

NASA Astrophysics Data System (ADS)

Urata, Yumi; Kuge, Keiko; Kase, Yuko

2013-11-01

investigated the effect of dilatancy on dynamic rupture propagation on a fault where thermal pressurization (TP) is in effect, taking into account permeability varying with porosity; the study is based on three-dimensional (3-D) numerical simulations of spontaneous ruptures obeying a slip-weakening friction law and Coulomb failure criterion. The effects of dilatancy on dynamic ruptures interacting with TP have been often investigated in one- or two-dimensional numerical simulations. The sole 3-D numerical simulation gave attention only to the behavior at a single point on a fault. Moreover, with the sole exception based on a single-degree-freedom spring-slider model, the previous simulations including dilatancy and TP have not considered changes in hydraulic diffusivity. However, the hydraulic diffusivity, which strongly affects TP, can vary as a power of porosity. In this study, we apply a power law relationship between permeability and porosity. We consider both reversible and irreversible changes in porosity, assuming that the irreversible change is proportional to the slip rate and dilatancy coefficient ɛ. Our numerical simulations suggest that the effects of dilatancy can suppress slip and rupture velocity increased by TP. The results reveal that the amount of slip on the fault decreases with increasing ɛ or exponent of the power law, and the rupture velocity is predominantly suppressed by ɛ. This was observed regardless of whether the applied stresses were high or low. The deficit of the final slip in relation to ɛ can be smaller as the fault size is larger.

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.

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

Esophageal dilation in head and neck cancer patients: A systematic review and meta-analysis.

PubMed

Moss, William J; Pang, John; Orosco, Ryan K; Weissbrod, Philip A; Brumund, Kevin T; Weisman, Robert A; Brigger, Matthew T; Coffey, Charles S

2018-01-01

To characterize the safety profile and effectiveness of esophageal dilation in head and neck cancer patients. A systematic review was undertaken for articles reporting outcomes of esophageal dilation in head and neck cancer patients. The Medline, Scopus, Web of Science, and Cochrane databases were searched in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Complications related to esophageal dilation in head and neck cancer patients was the primary outcome of interest. Success rates, demographic data, cancer staging, and treatment data were assessed secondarily. Statistical analyses included both qualitative and quantitative assessments. A limited meta-analysis and pooling of the data was performed using a random effects model. Of the collective 8,243 initial candidate articles, 15 retrospective studies containing data for a collective 449 patients were ultimately included in the analysis. There was significant heterogeneity in the outcomes data. With an overall complication rate of 10.6% (95% confidence interval [CI]: 4.1%,17%) and a pooled success rate of 72.9% (95% CI: 65.7%,80.1%) per patient, the articles generally supported the use of dilation. Head and neck cancer patients experience a higher rate of complications following dilation compared to patients with other causes of benign stricture. Esophageal dilation is effective in improving dysphagia, but these benefits are often transient and thus necessitate repeat interventions. Laryngoscope, 128:111-117, 2018. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

Discussion of “The relation between dilatancy, effective stress and dispersive pressure in granular avalanches” by P. Bartelt and O. Buser (DOI: 10.1007/s11440-016-0463-7)

USGS Publications Warehouse

Iverson, Richard M.; George, David L.

2016-01-01

A paper recently published by Bartelt and Buser (hereafter identified as “the authors”) aims to clarify relationships between granular dilatancy and dispersive pressure and to question the effective stress principle and its application to shallow granular avalanches (Bartelt and Buser in Act Geotech 11:549–557, 2). The paper also criticizes our own recent work, which utilizes the concepts of evolving dilatancy and effective stress to model the initiation and dynamics of water-saturated landslides and debris flows. Here we first explain why we largely agree with the authors’ views of dilatancy and dispersive pressure as they apply to depth-integrated granular avalanche models, and why we disagree with their views of effective stress and pore-fluid pressure. We conclude by explaining why the authors’ characterization of our recently developed D-Claw model is inaccurate.

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

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.

Altered focal adhesion regulation correlates with cardiomyopathy in mice expressing constitutively active rac1

PubMed Central

Sussman, Mark A.; Welch, Sara; Walker, Angela; Klevitsky, Raisa; Hewett, Timothy E.; Price, Robert L.; Schaefer, Erik; Yager, Karen

2000-01-01

The ras family of small GTP-binding proteins exerts powerful effects upon cell structure and function. One member of this family, rac, induces actin cytoskeletal reorganization in nonmuscle cells and hypertrophic changes in cultured cardiomyocytes. To examine the effect of rac1 activation upon cardiac structure and function, transgenic mice were created that express constitutively activated rac1 specifically in the myocardium. Transgenic rac1 protein was expressed at levels comparable to endogenous rac levels, with activation of the rac1 signaling pathway resulting in two distinct cardiomyopathic phenotypes: a lethal dilated phenotype associated with neonatal activation of the transgene and a transient cardiac hypertrophy seen among juvenile mice that resolved with age. Neither phenotype showed myofibril disarray and hypertrophic hearts were hypercontractilein working heart analyses. The rac1 target p21-activated kinase translocated from a cytosolic to a cytoskeletal distribution, suggesting that rac1 activation was inducing focal adhesion reorganization. Corroborating results showed altered localizations of src in dilated cardiomyopathy and paxillin in both cardiomyopathic phenotypes. This study, the first examination of rac1-mediated cardiac effects in vivo, demonstrates that dilation and hypertrophy can share a common molecular origin and presents evidence that both timing and concurrent signaling from multiple pathways can influence cardiac remodeling. PMID:10749567

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

The effects of uncinectomy and natural ostial dilatation on maxillary sinus ventilation: a clinical experimental study.

PubMed

Kutluhan, Ahmet; Şalvız, Mehti; Bozdemir, Kazım; Kanbak, Orhan; Ulu, Mustafa; Yalçıner, Gökhan; Bilgen, Akif Sinan

2011-04-01

The purpose of this study was to determine the effect of uncinectomy without sinusotomy and natural ostial dilatation on maxillary sinus ventilation in chronic rhinosinusitis. Twenty patients with chronic rhinosinusitis were included in this study. The patients were randomly divided into two groups. Group 1 consisted of patients with uncinectomy (n = 10), while group 2 was made up of patients treated with natural ostial dilatation (n = 10). The CO(2) tension and pressure levels of the maxillary sinus during inspiration and expiration phases were obtained and compared before and after the procedures within and between the groups. The mean CO(2) tension levels in both groups were significantly decreased after the procedures. The mean maxillary sinus pressure during inspiration was significantly decreased to a negative value after uncinectomy; however, no significant change was observed during expiration. There were no significant changes in maxillary sinus pressures after natural ostial dilatation procedure. Both uncinectomy and natural ostial dilatation seem to be equally effective in decreasing maxillary sinus pCO(2) levels. The effects of decreased maxillary sinus pressure during inspiration after uncinectomy on mucociliary clearance and development mechanisms of chronic rhinosinusitis seem to be worth investigating.

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.

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.

Crack Damage Parameters and Dilatancy of Artificially Jointed Granite Samples Under Triaxial Compression

NASA Astrophysics Data System (ADS)

Walton, G.; Alejano, L. R.; Arzua, J.; Markley, T.

2018-06-01

A database of post-peak triaxial test results was created for artificially jointed planes introduced in cylindrical compression samples of a Blanco Mera granite. Aside from examining the artificial jointing effect on major rock and rock mass parameters such as stiffness, peak strength and residual strength, other strength parameters related to brittle cracking and post-yield dilatancy were analyzed. Crack initiation and crack damage values for both the intact and artificially jointed samples were determined, and these damage envelopes were found to be notably impacted by the presence of jointing. The data suggest that with increased density of jointing, the samples transition from a combined matrix damage and joint slip yielding mechanism to yield dominated by joint slip. Additionally, post-yield dilation data were analyzed in the context of a mobilized dilation angle model, and the peak dilation angle was found to decrease significantly when there were joints in the samples. These dilatancy results are consistent with hypotheses in the literature on rock mass dilatancy.

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 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.

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.

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.

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.

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.

Face inversion effects in autism: a combined looking time and pupillometric study.

PubMed

Falck-Ytter, Terje

2008-10-01

Previous research has found that in typically developing individuals, behavioral performance declines and electrophysiological brain responses are altered when the face is inverted. Such effects are generally attributed to disruption of configural information. Individuals with autism spectrum disorder (ASD) have been found to show less pronounced inversion effects, a result in line with the view that featural processing of faces is enhanced in ASD. No study has determined if, or how, such local bias is reflected in the eye movements used in face observation. In this eye tracking study, looking time and pupil dilation were investigated during the presentation of upright and inverted faces in preschool children with ASD and typically developing preschoolers. On average, both children with ASD and typically developing children looked less at the face and the eye areas during inverted presentations than during upright presentations. Nevertheless, individuals with ASD had a stronger tendency than typically developing children to look at the same face features during upright and inverted presentations, which is suggestive of a local bias. Pupil dilation, reflecting increased processing load, was larger for inverted than upright faces in the ASD group only, and pupillary inversion effects were stronger in ASD than in typically developing children.

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.

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.

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

Wavelet transforms with discrete-time continuous-dilation wavelets

NASA Astrophysics Data System (ADS)

Zhao, Wei; Rao, Raghuveer M.

1999-03-01

Wavelet constructions and transforms have been confined principally to the continuous-time domain. Even the discrete wavelet transform implemented through multirate filter banks is based on continuous-time wavelet functions that provide orthogonal or biorthogonal decompositions. This paper provides a novel wavelet transform construction based on the definition of discrete-time wavelets that can undergo continuous parameter dilations. The result is a transformation that has the advantage of discrete-time or digital implementation while circumventing the problem of inadequate scaling resolution seen with conventional dyadic or M-channel constructions. Examples of constructing such wavelets are presented.

Difficulty in tracheal extubation followed by tracheal collapse after balloon dilatation for tracheal stenosis therapy: A case report.

PubMed

Li, Nana; Zhu, Linjia; Sun, Jie; Pan, Yinbing; Gao, Mei

2018-06-01

Tracheobronchomalacia (TBM) refers to the weakening trachea or the trachea loss of structural integrity of airway cartilaginous structures. It causes tracheal stenosis, resulting in significantly high rates of mortality. Bronchoplasty by high-pressure balloon dilation under general anesthesia is a simple but effective and safe method to treat tracheobronchial stenosis. However, recurrent postoperative dyspnea after extubation due to tracheal collapse is still a challenge for anesthetists. A 52-year-old man weighing 72 kg was scheduled for balloon dilatation surgery under general anesthesia because of breathing difficulties caused by tracheal stenosis. His previous medical history included rheumatoid arthritis, obstructive sleep apnea syndrome (OSAS), chronic bronchitis and a history of tracheal intubation. Laryngeal computerized tomography confirmed the stenosis at the level of thyroid gland. The tracheal collapse after balloon dilatation for tracheal stenosis therapy. Postoperatively, the patient presented with more serious and repetitive symptoms of dyspnea after extubation when compared to that before treatment. So, we had to re-insert the laryngeal mask airway (LMA), and exclude some anesthesia-associated factors, such as laryngospasm, bronchospasm and so on. After a series of treatments, we ultimately found the cause in time (the airway collapsed), and succeeded in tracheal extubation after the stent was inserted. The patient recovered well and reported high satisfaction with anesthesia management. In such an emergency even, the anesthesiologist should take valuable treatments to ensure the patient's effective ventilation. If the anesthesia-related factors can be eliminated, tracheomalacia or airway collapse should be considered whenever dyspnea occurs in the patients who unexpectedly fail to be extubated.

Update on second-trimester surgical abortion.

PubMed

Shaw, Kate A; Lerma, Klaira

2016-12-01

To review the recent literature on surgical second-trimester abortion, with specific attention to cervical preparation techniques. Confirming previous studies, a recent retrospective observational cohort study, including 54 911 abortions, estimated the total abortion-related complication rate to be 0.41% for second-trimester or later procedures. Cervical preparation is known to reduce risks associated with second-trimester dilation and evacuation (D&E). When considering adjuncts to osmotic dilators for cervical preparation prior to D&E after 16 weeks, both misoprostol and mifepristone are effective alone and in combination or as adjuncts to osmotic dilators. Misoprostol consistently has been shown to cause more pain and cramping than placebo, but is an effective adjunct to osmotic dilators after 16 weeks. Although mifepristone has fewer side-effects, at its current price, it may not be as cost-effective as misoprostol. Second-trimester abortion is safe. The use of mifepristone and misoprostol for second-trimester abortion has improved safety and efficacy of medical and surgical methods when used alone or in combination and as adjuncts to osmotic dilators. An important aspect of D&E, cervical preparation, is not a one-size-fits-all practice; the approach and methods are contingent on patient, provider and setting and should consider all the evidence-based options.

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.

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.

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.

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.

Autoantibodies against β1 receptor and AT1 receptor in type 2 diabetes patients with left ventricular dilatation.

PubMed

Zhao, Linshuang; Xu, Chunyan; Xu, Jinling

2014-01-01

To explore the relationship between the autoantibodies against the β1 and AT1 receptors and left ventricular dilatation in patients with type 2 diabetes (T2DM). The autoantibodies against the β1 and angiotensin II type 1 (AT1) receptors of T2DM patients with and without hypertension were screened by ELISA. Multiple logistic regression was used to analyze the risk factors for left ventricular dilatation. The reversing effect of left ventricular dilatation was evaluated after receptor blocker treatment. The positive rates of autoantibodies against the β1 and AT1 receptors (43.0 and 44.1%, respectively) in T2DM patients with hypertension were significantly higher than those in normotensive patients (16.0 and 10.4%, respectively; all p < 0.01). Furthermore, among T2DM patients with hypertension, the positive rates (61.4 and 64.9%, respectively) in patients with left ventricular dilatation were remarkably higher than those with normal left ventricular dimensions (34.4 and 36.1%, respectively; all p < 0.01). The presence of β1 receptor antibody and AT1 receptor antibody were risk factors for left ventricular dilatation (p < 0.05). The curative effect of metoprolol tartrate and valsartan in reversing left ventricular hypertrophy in the group positive for autoantibodies was much better than in the negative group. The findings show that autoantibodies against the β1 and AT1 receptors may play a role in predicting left ventricular dilatation in T2DM patients in combination with hypertension. Metoprolol tartrate and valsartan are effective and safe in the treatment of these patients. © 2014 S. Karger AG, Basel.

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.

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.

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.

A Light Clock Satisfying the Clock Hypothesis of Special Relativity

ERIC Educational Resources Information Center

West, Joseph

2007-01-01

The design of the FMEL, a floor-mirrored Einstein-Langevin "light clock", is introduced. The clock provides a physically intuitive manner to calculate and visualize the time dilation effects for a spatially extended set of observers (an accelerated "frame") undergoing unidirectional acceleration or observers on a rotating cylinder of constant…

Viscosity of particle laden films

NASA Astrophysics Data System (ADS)

Timounay, Yousra; Rouyer, Florence

2017-06-01

We perform retraction experiments on soap films where large particles bridge the two interfaces. Local velocities are measured by PIV during the unstationnary regime. The velocity variation in time and space can be described by a continuous fluid model from which effective viscosity (shear and dilatational) of particulate films is measured. The 2D effective viscosity of particulate films η2D increases with particle surface fraction ϕ: at low ϕ, it tends to the interfacial dilatational viscosity of the liquid/air interfaces and it diverges at the critical particle surface fraction ϕc ≃ 0.84. Experimental data agree with classical viscosity laws of hard spheres suspensions adapted to the 2D geometry, assuming viscous dissipation resulting from the squeeze of the liquid/air interfaces between the particles. Finally, we show that the observed viscous dissipation in particulate films has to be considered to describe the edge velocity during a retraction experiment at large particle coverage.

Effect of cataract surgery and pupil dilation on iris pattern recognition for personal authentication.

PubMed

Dhir, L; Habib, N E; Monro, D M; Rakshit, S

2010-06-01

The purpose of this study was to investigate the effect of cataract surgery and pupil dilation on iris pattern recognition for personal authentication. Prospective non-comparative cohort study. Images of 15 subjects were captured before (enrolment), and 5, 10, and 15 min after instillation of mydriatics before routine cataract surgery. After cataract surgery, images were captured 2 weeks thereafter. Enrolled and test images (after pupillary dilation and after cataract surgery) were segmented to extract the iris. This was then unwrapped onto a rectangular format for normalization and a novel method using the Discrete Cosine Transform was applied to encode the image into binary bits. The numerical difference between two iris codes (Hamming distance, HD) was calculated. The HD between identification and enrolment codes was used as a score and was compared with a confidence threshold for specific equipment, giving a match or non-match result. The Correct Recognition Rate (CRR) and Equal Error Rates (EERs) were calculated to analyse overall system performance. After cataract surgery, perfect identification and verification was achieved, with zero false acceptance rate, zero false rejection rate, and zero EER. After pupillary dilation, non-elastic deformation occurs and a CRR of 86.67% and EER of 9.33% were obtained. Conventional circle-based localization methods are inadequate. Matching reliability decreases considerably with increase in pupillary dilation. Cataract surgery has no effect on iris pattern recognition, whereas pupil dilation may be used to defeat an iris-based authentication system.

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

Yagci, Cemil, E-mail: cemil.yagci@medicine.ankara.edu.tr; Ustuner, Evren, E-mail: evrenustuner@hotmail.com; Atman, Ebru Dusunceli, E-mail: ebrumd2001@yahoo.com

Percutaneous nephrostomy (PCN) in a nondilated pelvicaliceal system is technically challenging. We describe an effective method to achieve transient dilatation of the pelvicaliceal system via induction of diuresis using infusion of a diuretic agent in normal saline, therefore allowing easier access to the pelvicaliceal system. Under real-time ultrasound guidance, the technique had been tested in 22 nephrostomies with nondilated system (a total of 20 patients with 2 patients having bilateral nephrostomies) during a 5-year period. Patients were given 40 mg of furosemide in 250 ml of normal saline solution intravenously by rapid infusion. As soon as maximum calyceal dilatation ofmore » more than 5 mm was observed, which is usually 15 min later after the end of rapid infusion, patients were positioned obliquely, and PCN procedure under ultrasound guidance was performed. The procedure was successful in 19 of the nephrostomies in 17 patients with a success rate of 86.36 % per procedure and 85 % per patient in nondilated pelvicaliceal systems. No major nephrostomy-, drug-, or technique-related complications were encountered. The technique failed to work in three patients due to the presence of double J catheters and preexisting calyceal perforation which avoided transient dilation of the pelvicaliceal system with diuresis. Diuretic infusion in saline is a feasible and effective method for PCN in nondilated pelvicaliceal systems.« less

Obstructive sleep apnea.

PubMed

White, David P; Younes, Magdy K

2012-10-01

Obstructive sleep apnea (OSA) is a common disorder characterized by repetitive collapse of the pharyngeal airway during sleep. Control of pharyngeal patency is a complex process relating primarily to basic anatomy and the activity of many pharyngeal dilator muscles. The control of these muscles is regulated by a number of processes including respiratory drive, negative pressure reflexes, and state (sleep) effects. In general, patients with OSA have an anatomically small airway the patency of which is maintained during wakefulness by reflex-driven augmented dilator muscle activation. At sleep onset, muscle activity falls, thereby compromising the upper airway. However, recent data suggest that the mechanism of OSA differs substantially among patients, with variable contributions from several physiologic characteristics including, among others: level of upper airway dilator muscle activation required to open the airway, increase in chemical drive required to recruit the pharyngeal muscles, chemical control loop gain, and arousal threshold. Thus, the cause of sleep apnea likely varies substantially between patients. Other physiologic mechanisms likely contributing to OSA pathogenesis include falling lung volume during sleep, shifts in blood volume from peripheral tissues to the neck, and airway edema. Apnea severity may progress over time, likely due to weight gain, muscle/nerve injury, aging effects on airway anatomy/collapsibility, and changes in ventilatory control stability. © 2012 American Physiological Society

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.

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).

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.

Intermittent self-dilatation for urethral stricture disease in males.

PubMed

Jackson, Matthew J; Veeratterapillay, Rajan; Harding, Chris K; Dorkin, Trevor J

2014-12-19

Intermittent urethral self-dilatation is sometimes recommended to reduce the risk of recurrent urethral stricture. There is no consensus as to whether it is a clinically effective or cost-effective intervention in the management of this disease. The purpose of this review is to evaluate the clinical effectiveness and cost-effectiveness of intermittent self-dilatation after urethral stricture surgery in males compared to no intervention. We also compared different programmes of, and devices for, intermittent self-dilatation. . We searched the Cochrane Incontinence Group Specialised Register (searched 7 May 2014), CENTRAL (2014, Issue 4), MEDLINE (1 January 1946 to Week 3 April 2014), PREMEDLINE (covering 29 April 2014), EMBASE (1 January 1947 to Week 17 2014), CINAHL (31 December 1981 to 30 April 2014) OpenGrey (searched 6 May 2014), ClinicalTrials.gov (6 May 2014), WHO International Clinical Trials Registry Platform (6 May 2014), Current Controlled Trials (6 May 2014) and the reference lists of relevant articles. Randomised and quasi-randomised trials where one arm was a programme of intermittent self-dilatation for urethral stricture were identified. Studies were excluded if they were not randomised or quasi-randomised trials, or if they pertained to clean intermittent self-catheterisation for bladder emptying. Two authors screened the records for relevance and methodological quality. Data extraction was performed according to predetermined criteria using data extraction forms. Analyses were carried out in Cochrane Review Manager (RevMan 5). The primary outcomes were patient-reported symptoms and health-related quality of life, and risk of recurrence; secondary outcomes were adverse events, acceptability of the intervention to patients and cost-effectiveness. Quality of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Eleven trials were selected for inclusion in the review, including a total of 776 men. They were generally small; all were of poor quality and all were deemed to have high risk of bias. Performing intermittent self-dilatation versus not performing intermittent self-dilatation The data from six trials were heterogeneous, imprecise and had a high risk of bias, but indicated that recurrent urethral stricture was less likely in men who performed intermittent self-dilatation than men who did not perform intermittent self-dilatation (RR 0.70, 95% CI 0.48 to 1.00; very low quality evidence). Adverse events were generally poorly reported: two trials did not report adverse events and two trials reported adverse events only for the intervention group. Meta-analysis of the remaining two trials found no evidence of a difference between performing intermittent self-dilatation and not performing it (RR 0.60, 95% CI 0.11 to 3.26). No trials formally assessed acceptability, and no trials reported on patient-reported lower urinary tract symptoms, patient-reported health-related quality of life, or cost-effectiveness. One programme of intermittent self-dilatation versus another We identified two trials that compared different durations of intermittent self-dilatation, but data were not combined. One study could not draw robust conclusions owing to cross-over, protocol deviation, administrative error, post-hoc analysis and incomplete outcome reporting. The other study found no evidence of a difference between intermittent self-dilatation for six months versus for 12 months after optical urethrotomy (RR 0.67, 95% CI 0.12 to 3.64), although again the evidence is limited by the small sample size and risk of bias in the included study. Adverse events were reported narratively and were not stratified by group. No trials formally assessed acceptability, and no trials reported on patient-reported lower urinary tract symptoms, patient-reported health-related quality of life, or cost-effectiveness. One device for performing intermittent self-dilatation versus another Three trials compared one device for performing intermittent self-dilatation with another. Results from one trial at a high risk of bias were too uncertain to determine the effects of a low friction hydrophilic catheter and a standard polyvinyl chloride catheter on the risk of recurrent urethral stricture (RR 0.32, 95% CI 0.07 to 1.40). Similarly one study did not find evidence of a difference between one percent triamcinolone gel for lubricating the intermittent self-dilatation catheter versus water-based gel on risk of recurrent urethral stricture (RR 0.68, 95% CI 0.35 to 1.32). Two trials reported adverse events, but one did not provide sufficient detail for analysis. The other small study reported fewer instances of prostatitis, urethral bleeding or bacteriuria with a low friction hydrophilic catheter compared with a standard polyvinyl chloride catheter (RR 0.13, 95% CI 0.02 to 0.98). 'Happiness with the intervention' was assessed using a non-validated scale in one study, but no trials formally assessed patient-reported health-related quality of life or acceptability. No trials reported on patient-reported lower urinary tract symptoms or cost-effectiveness. GRADE quality assessment The evidence that intermittent self-dilatation reduces the risk of recurrent urethral stricture after surgical intervention was downgraded to 'very low' on the basis that the studies comprising the meta-analysis were deemed to have high risk of bias, and the data was imprecise and inconsistent. Insufficient evidence No trials provided cost-effectiveness data or used a validated patient-reported outcome measure, and adverse events were not reported rigorously. Acceptability of the intervention to patients has not been assessed quantitatively or qualitatively. Performing intermittent self-dilatation may confer a reduced risk of recurrent urethral stricture after endoscopic treatment. We have very little confidence in the estimate of the effect owing to the very low quality of the evidence. Evidence for other comparisons and outcomes is limited. Further research is required to determine whether the apparent benefit is sufficient to make the intervention worthwhile, and in whom.

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.

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.

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

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.

In a Concurrent Memory and Auditory Perception Task, the Pupil Dilation Response Is More Sensitive to Memory Load Than to Auditory Stimulus Characteristics.

PubMed

Zekveld, Adriana A; Kramer, Sophia E; Rönnberg, Jerker; Rudner, Mary

2018-06-19

Speech understanding may be cognitively demanding, but it can be enhanced when semantically related text cues precede auditory sentences. The present study aimed to determine whether (a) providing text cues reduces pupil dilation, a measure of cognitive load, during listening to sentences, (b) repeating the sentences aloud affects recall accuracy and pupil dilation during recall of cue words, and (c) semantic relatedness between cues and sentences affects recall accuracy and pupil dilation during recall of cue words. Sentence repetition following text cues and recall of the text cues were tested. Twenty-six participants (mean age, 22 years) with normal hearing listened to masked sentences. On each trial, a set of four-word cues was presented visually as text preceding the auditory presentation of a sentence whose meaning was either related or unrelated to the cues. On each trial, participants first read the cue words, then listened to a sentence. Following this they spoke aloud either the cue words or the sentence, according to instruction, and finally on all trials orally recalled the cues. Peak pupil dilation was measured throughout listening and recall on each trial. Additionally, participants completed a test measuring the ability to perceive degraded verbal text information and three working memory tests (a reading span test, a size-comparison span test, and a test of memory updating). Cue words that were semantically related to the sentence facilitated sentence repetition but did not reduce pupil dilation. Recall was poorer and there were more intrusion errors when the cue words were related to the sentences. Recall was also poorer when sentences were repeated aloud. Both behavioral effects were associated with greater pupil dilation. Larger reading span capacity and smaller size-comparison span were associated with larger peak pupil dilation during listening. Furthermore, larger reading span and greater memory updating ability were both associated with better cue recall overall. Although sentence-related word cues facilitate sentence repetition, our results indicate that they do not reduce cognitive load during listening in noise with a concurrent memory load. As expected, higher working memory capacity was associated with better recall of the cues. Unexpectedly, however, semantic relatedness with the sentence reduced word cue recall accuracy and increased intrusion errors, suggesting an effect of semantic confusion. Further, speaking the sentence aloud also reduced word cue recall accuracy, probably due to articulatory suppression. Importantly, imposing a memory load during listening to sentences resulted in the absence of formerly established strong effects of speech intelligibility on the pupil dilation response. This nullified intelligibility effect demonstrates that the pupil dilation response to a cognitive (memory) task can completely overshadow the effect of perceptual factors on the pupil dilation response. This highlights the importance of taking cognitive task load into account during auditory testing.This is an open access article distributed under the Creative Commons Attribution License 4.0 (CCBY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Balloon or bougie for dilatation of benign oesophageal stricture? An interim report of a randomised controlled trial.

PubMed Central

Cox, J G; Winter, R K; Maslin, S C; Jones, R; Buckton, G K; Hoare, R C; Sutton, D R; Bennett, J R

1988-01-01

Seventy one patients with benign oesophageal strictures were randomised to receive balloon or bougie dilatation. Sixty five patients were eligible for analysis. At the end of five months the balloon group had significantly more dysphagia and the calibre of the strictures in the balloon group had narrowed by a greater degree. The methods were equally safe and acceptable to patients. While the choice of the method of dilatation depends on the individual patient's needs and operator experience, bougie dilatation is more effective in reducing dysphagia and maintaining stricture patency. Images Fig. 2 Fig. 3 PMID:3065156

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.

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.

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.

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

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).

The calming effect of oil on water

NASA Astrophysics Data System (ADS)

Behroozi, Peter; Cordray, Kimberly; Griffin, William; Behroozi, Feredoon

2007-05-01

The calming effect of oil on water has been known since ancient times. Benjamin Franklin was the first to investigate the effect, but the underlying mechanism for this striking phenomenon remains elusive. We used a miniature laser interferometer to measure the amplitude of surface waves to a resolution of ±5nm, making it possible to determine the effect of an oil monolayer on the attenuation of capillary waves and the surface dilational modulus of the monolayer. We present attenuation data on pure water, water covered by olive oil, water covered by a fatty acid, and a water-acetone mixture for comparison. From the attenuation data at frequencies between 251 and 551Hz, we conclude that the calming effect of oil on surface waves is principally due to the dissipation of wave energy caused by the Gibbs surface elasticity of the monolayer, with only a secondary contribution from the reduction in surface tension. Our data also indicate that the surface-dilational viscosity of the oil monolayer is negligible and plays an insignificant role in calming the waves.

[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 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.

Vasomotor response to cold stimulation in human capsaicin-induced hyperalgesic area.

PubMed

Pud, Dorit; Andersen, Ole Kaeseler; Arendt-Nielsen, Lars; Eisenberg, Elon; Yarnitsky, David

2005-07-01

Cooling the skin induces sympathetically driven vasoconstriction, with some vasoparalytic dilatation at the lowest temperatures. Neurogenic inflammation, on the other hand, entails vasodilatation. In this study we investigated the balance between vasoconstriction and vasodilatation in an area of experimentally induced secondary hyperalgesia (2 degrees HA), in response to low-temperature stimulations. Fourteen healthy volunteers were exposed to three 30-s long cold stimuli (20, 10, and 0 degrees C) applied, at three adjacent sites, before (baseline) and 8 min after intradermal injection of 50 microg capsaicin to the volar forearm. The cold stimuli were applied distally to the injection site within the 2 degrees HA. Blood flux (BF) and skin temperatures were measured at four different regions (proximally, and distally to the capsaicin injection and at the 0, 10, and 20 degrees C thermode sites) all within the 2 degrees HA. The vascular measurements were conducted five times. Results showed a marked increase in BF after baseline cold stimulation (P<0.001) at the 0 degrees C compared with the three other sites. In addition, vasodilatory effect (elevated BF) was found following the capsaicin injection compared with baseline for all regions (P<0.001): the non-cooled area was dilated by 450+/-5.1%; The vasoconstrictive effect for the 10 and 20 degrees C did not overcome the capsaicin vasodilatation, but did reduce it, with dilatation of 364+/-7.0% and 329+/-7.3%, respectively. For 0 degrees C, a dilatation of 407+/-6.5% was seen. It is concluded that in this experimental model, and potentially in the equivalent clinical syndromes, vasodilatation induced by the inflammation is only slightly reduced by cold stimulation such that it is still dominant, despite some cold-induced vasoconstriction.

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.

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.

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.

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.

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.

H1- and H2-receptor characterization in the tracheal circulation of sheep.

PubMed Central

Webber, S. E.; Salonen, R. O.; Widdicombe, J. G.

1988-01-01

1. The effects of histamine, the specific H1-agonist SKF 71481-A2 and the H2-agonist dimaprit were examined on tracheal vascular resistance in sheep anaesthetized with pentobarbitone. Tracheal vascular resistance was determined by perfusing the cranial tracheal arteries at constant flows and measuring inflow pressures. Changes in tracheal smooth muscle tone were also measured. 2. Histamine and SKF 71481-A2 contracted the tracheal smooth muscle and this effect was blocked by the H1-antagonist mepyramine. Stimulation of H2-receptors with dimaprit had no effect on tracheal smooth muscle tone. 3. Histamine had a complex action on the tracheal vasculature producing either a triphasic change (early dilatation then constriction followed by late dilatation) or just a constriction. SKF 71481-A2 always produced a biphasic change in vascular resistance (dilatation followed by constriction). Dimaprit dilated the tracheal vasculature. 4. The late dilatation produced by histamine in some sheep was blocked by bilateral cervical vagotomy but the mechanism for this effect is not known. No other responses to histamine, SKF 71481-A2 or dimaprit were affected by vagotomy. 5. The vasoconstriction produced by histamine and SKF 71481-A2 was antagonized by mepyramine indicating a H1-receptor-mediated effect. Cimetidine had no effect on the vasoconstriction to histamine suggesting a lack of involvement of H2-receptors. 6. The vasodilatation produced by histamine and SKF 71481-A2 was also antagonized by mepyramine, again suggesting a H1-receptor-mediated action. Cimetidine had no effect on the vasodilator response to histamine indicating no involvement of H2-receptors in this response. 7. The dilator effect of dimaprit was antagonized by cimetidine suggesting this effect was mediated by H2-receptors. 8. We conclude that H1-receptors in the various parts of the sheep tracheal vasculature can cause increases and decreases in total tracheal vascular resistance; that H2-receptors decrease resistance; and that the tracheal smooth muscle contracts on activation of H1-receptors but has no response to H2-agonists. PMID:2906559

Endoscopic balloon dilatation as an effective treatment for lower and upper benign gastrointestinal system anastomotic stenosis.

PubMed

Akarsu, Cevher; Unsal, Mustafa Gokhan; Dural, Ahmet Cem; Kones, Osman; Kocatas, Ali; Karabulut, Mehmet; Kankaya, Burak; Ates, Mustafa; Alis, Halil

2015-04-01

Endoscopic balloon dilatation (EBD) is currently accepted as an effective, safe, and first-line treatment of postoperative benign gastrointestinal anastomosis stenosis (BGAS); however, a limited number of publications on the subject exist in the literature. The aim of the study was to retrospectively evaluate the efficiency of endoscopic dilatation in patients with postoperative intestinal anastomotic stenoses at a single surgical center. Patients with postoperative BGAS treated by EBD at our institution from February 2008 to 2012 were included. The dilatations were all performed using through-the-scope balloons. The balloon was introduced into the stricture using a guidewire under radiologic guidance. Each dilatation session consisted of 2 to 3 two-minute multistep inflations of the balloon until adequate dilatation was achieved. Of the 48 patients included in the study, 44 patients (91.7%) fully recovered and 4 (8.3%) did not respond to treatment. The mean follow-up period was 24 months (range, 3 to 57 mo). Four patients who did not respond to the procedure were treated surgically. Two patients (4.1%) with intestinal perforation during EBD were treated conservatively with a stent. EBD has a low rate of complications and a high success rate, is well tolerated, and avoids further surgical procedures for BGAS. Therefore, EBD should be the first choice of treatment for postoperative anastomotic stenoses.

The cost-effectiveness of Welcome to Medicare visual acuity screening and a possible alternative welcome to medicare eye evaluation among persons without diagnosed diabetes mellitus.

PubMed

Rein, David B; Wittenborn, John S; Zhang, Xinzhi; Hoerger, Thomas J; Zhang, Ping; Klein, Barbara Eden Kobrin; Lee, Kris E; Klein, Ronald; Saaddine, Jinan B

2012-05-01

To estimate the cost-effectiveness of visual acuity screening performed in primary care settings and of dilated eye evaluations performed by an eye care professional among new Medicare enrollees with no diagnosed eye disorders. Medicare currently reimburses visual acuity screening for new enrollees during their initial preventive primary care health check, but dilated eye evaluations may be a more cost-effective policy. Monte Carlo cost-effectiveness simulation model with a total of 50 000 simulated patients with demographic characteristics matched to persons 65 years of age in the US population. Compared with no screening policy, dilated eye evaluations increased quality-adjusted life-years(QALYs) by 0.008 (95% credible interval [CrI], 0.005-0.011) and increased costs by $94 (95% CrI, −$35 to$222). A visual acuity screening increased QALYs in less than 95% of the simulations (0.001 [95% CrI, −0.002 to 0.004) and increased total costs by $32 (95% CrI, −$97 to $159) per person. The incremental cost-effectiveness ratio of a visual acuity screening and an eye examination compared with no screening were $29 000 and$12 000 per QALY gained, respectively. At a willingness-to-pay value of $15 000 or more per QALY gained, a dilated eye evaluation was the policy option most likely to be cost-effective. The currently recommended visual acuity screening showed limited efficacy and cost-effectiveness compared with no screening. In contrast, anew policy of reimbursement for Welcome to Medicare dilated eye evaluations was highly cost-effective.

The Cost-effectiveness of Welcome to Medicare Visual Acuity Screening and a Possible Alternative Welcome to Medicare Eye Evaluation Among Persons Without Diagnosed Diabetes Mellitus

PubMed Central

Rein, David B.; Wittenborn, John S.; Zhang, Xinzhi; Hoerger, Thomas J.; Zhang, Ping; Klein, Barbara Eden Kobrin; Lee, Kris E.; Klein, Ronald; Saaddine, Jinan B.

2013-01-01

Objective To estimate the cost-effectiveness of visual acuity screening performed in primary care settings and of dilated eye evaluations performed by an eye care professional among new Medicare enrollees with no diagnosed eye disorders. Medicare currently reimburses visual acuity screening for new enrollees during their initial preventive primary care health check, but dilated eye evaluations may be a more cost-effective policy. Design Monte Carlo cost-effectiveness simulation model with a total of 50 000 simulated patients with demographic characteristics matched to persons 65 years of age in the US population. Results Compared with no screening policy, dilated eye evaluations increased quality-adjusted life-years (QALYs) by 0.008 (95% credible interval [CrI], 0.005–0.011) and increased costs by $94 (95% CrI, −$35 to $222). A visual acuity screening increased QALYs in less than 95% of the simulations (0.001 [95% CrI, −0.002 to 0.004) and increased total costs by $32 (95% CrI, −$97 to $159) per person. The incremental cost-effectiveness ratio of a visual acuity screening and an eye examination compared with no screening were $29 000 and $12 000 per QALY gained, respectively. At a willingness-to-pay value of $15 000 or more per QALY gained, a dilated eye evaluation was the policy option most likely to be cost-effective. Conclusions The currently recommended visual acuity screening showed limited efficacy and cost-effectiveness compared with no screening. In contrast, a new policy of reimbursement for Welcome to Medicare dilated eye evaluations was highly cost-effective. PMID:22232367

Electrophysiological effects of acute atrial stretch on persistent atrial fibrillation in patients undergoing open heart surgery.

PubMed

Elvan, Arif; Adiyaman, Ahmet; Beukema, Rypko J; Sie, Hauw T; Allessie, Maurits A

2013-03-01

The electrophysiologic effects of acute atrial dilatation and dedilatation in humans with chronic atrial fibrillation remains to be elucidated. To study the electrophysiological effects of acute atrial dedilatation and subsequent dilatation in patients with long-standing persistent atrial fibrillation (AF) with structural heart disease undergoing elective cardiac surgery. Nine patients were studied. Mean age was 71 ± 10 years, and left ventricular ejection was 46% ± 6%. Patients had at least moderate mitral valve regurgitation and dilated atria. After sternotomy and during extracorporal circulation, mapping was performed on the beating heart with 2 multielectrode arrays (60 electrodes each, interelectrode distance 1.5 mm) positioned on the lateral wall of the right atrium (RA) and left atrium (LA). Atrial pressure and size were altered by modifying extracorporal circulation. AF electrograms were recorded at baseline after dedilation and after dilatation of the atria afterward. At baseline, the median AF cycle length (mAFCL) was 184 ± 27 ms in the RA and 180 ± 17 ms in the LA. After dedilatation, the mAFCL shortened significantly to 168 ± 13 ms in the RA and to 168 ± 20 ms in the LA. Dilatation lengthened mAFCL significantly to 189 ± 17 ms in the RA and to 185 ± 23 ms in the LA. Conduction block (CB) at baseline was 14.3% ± 3.6% in the RA and 17.3% ± 5.5% in the LA. CB decreased significantly with dedilatation to 7.4% ± 2.9% in the RA and to 7.9% ± 6.3% in the LA. CB increased significantly with dilatation afterward to 15.0% ± 8.3% in the RA and to 18.5% ± 16.0% in the LA. Acute dedilatation of the atria in patients with long-standing persistent AF causes a decrease in the mAFCL in both atria. Subsequent dilatation increased the mAFCL. The amount of CB decreased with dedilatation and increased with dilatation afterward in both atria. Copyright © 2013 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Compressibility Effects on the Passive Scalar Flux Within Homogeneous Turbulence

NASA Technical Reports Server (NTRS)

Blaisdell, G. A.; Mansour, N. N.; Reynolds, W. C.

1994-01-01

Compressibility effects on turbulent transport of a passive scalar are studied within homogeneous turbulence using a kinematic decomposition of the velocity field into solenoidal and dilatational parts. It is found that the dilatational velocity does not produce a passive scalar flux, and that all of the passive scalar flux is due to the solenoidal velocity.

Percutaneous Transhepatic Cutting Balloon Papillotomy for Removal of Common Bile Duct Stones

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

Oguzkurt, Levent, E-mail: loguzkurt@yahoo.com; Ozkan, Ugur; Gumus, Burcak

2009-09-15

We report the case of a 66-year-old female who presented with jaundice secondary to recurrent adenocarcinoma of the gallbladder and several common bile duct stones. Percutaneous papillary dilatation was planned to remove the common bile duct stones. Papilla was dilated through the percutaneous approach with an 8-mm peripheral cutting balloon instead of a standard balloon. All the stones were pushed successfully into the duodenum with a saline flush. No complications were encountered. Use of a peripheral cutting balloon for dilatation of the papilla seems to be safe and effective because it has the advantage of controlled incision and dilatation ofmore » the target at low pressures.« less

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.

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.

Discontinuous Shear Thickening and Dilatancy: Frictional Effects in Viscous Suspensions

NASA Astrophysics Data System (ADS)

Morris, Jeffrey

2015-03-01

Shear thickening in concentrated suspensions has been well-known for quite a long time, yet a firm consensus on the basis for very abrupt or ``discontinuous'' shear thickening (DST) seen in suspensions of large solid fraction, ϕ, has not been reached. This work addresses the DST phenomenon, and proposes a simulation method based in the Stokesian Dynamics algorithm to explore the role of various forces between the particles, including hydrodynamic, conservative potential, and frictional interactions. This work shows that allowance for friction between spherical particles suspended in a viscous liquid causes a significant reduction in the jamming solid fraction of the mixture, ϕmax, taken as the maximum fraction at which the suspension will flow. A consequence of this is a shifting of the singularity in the effective viscosity, η, to smaller ϕmax, and the frictional suspension has a larger viscosity than does the frictionless suspension of the same solid fraction, as is clear from the standard empirical modeling of η (ϕ) =(1 - ϕ /ϕmax) - α , α ~ 2 . When a counterbalancing repulsive force between the particles, representative for example of charge-induced repulsion, is incorporated in the dynamics, the mixture undergoes a transition from frictionless to frictional interactions, and from low to high effective viscosity, at a critical shear rate. Comparison with experimental data shows remarkable agreement in the features of DST captured by the method. The basic algorithm and results of both rate-controlled and stress-controlled simulations will be presented. Like the shear stress, the magnitude of the normal stress exerted by the suspended particles also increases abruptly at the critical shear rate, consistent with the long-standing notion that dilatancy and shear-thickening are synonymous. We will show that considering all shear thickening materials as dilatant is a misconception, but demonstrate the validity of the connection of dilatancy with DST in concentrated suspensions.

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.

Plummer-Vinson Syndrome with Proximal Esophageal Web.

PubMed

Changela, Kinesh; Haeri, Nami Safai; Krishnaiah, Mahesh; Reddy, Madhavi

2016-05-01

Plummer-Vinson Syndrome is a condition where iron deficiency is associated with difficulty swallowing due to the presence of an esophageal web. Deficiency of iron-dependent oxidative enzymes causes gradual degradation of the pharyngeal muscles which lead to mucosal atrophy and formation of webs. Although it is a very rare condition, an increased risk of esophageal squamous cell carcinoma makes its identification very important. Dilation of the esophageal web using a Savary dilator is a more effective and safer approach compared to conventional balloon dilation.

Comparing the efficacy of mydriatic cocktail-soaked sponge and conventional pupil dilation in patients using tamsulosin - a randomized controlled trial.

PubMed

Hargitai, János; Vezendi, László; Vigstrup, Jørgen; Eisgart, Finn; Lundbye-Christensen, Søren; Hargitai, Bálint; Vorum, Henrik

2013-12-20

A strong association exists between the use of tamsulosin and the occurance of intraoperative floppy iris syndrome. Several methods were advocated to overcome the progressive intraopertive miosis.Our purpose was to investigate the effect of a mydriatic-cocktail soaked cellulose sponge on perioperative pupil diameter in tamsulosin-treated patients undergoing elective cataract surgery. Patients using tamsulosin were dilated either with mydriatic-cocktail soaked sponge (group 1) or with conventional eyedrop regimen (group 2). Control patients not taking any α1 adrenergic receptor inhibtors were also dilated with mydriatic sponge (group 3).In all groups oxybuprocain 0.4%, cocain 4%, tropicamide 1%, phenylephrine 10%, diclophenac 0.1% along with chloramphenicol 0.5% were used preoperatively.Pupil diameter (mm) was measured preoperatively, after nucleus delivery, and before IOL implantation. Adverse effects associated with the use of sponge, minor and major intraoperative complications, the use of iris retractors and operation time were recorded.Differences in general between groups were analyzed with a one way analysis of variance (ANOVA); differences between groups in proportions were assessed by Fisher's exact test. Mean pupil diameter (mm) was preopertively: 7.52 ± 1.21, 7.30 ± 1.55 and 7.99 ± 0.96 (ANOVA: p = 0.079); after nucleus delivery: 6 ± 1.20, 6.29 ± 1.12 and 6.52 ± 0.81 (ANOVA: p = 0.123); before IOL implantation: 5.46 ± 1.06, 5.83 ± 1.09 and 6.17 ± 0.89 (ANOVA: p = 0.0291).No adverse effect related to sponge use was detected. Frequency of minor complications, and iris hook use was similar in the two tamsulosin treated group. Operation time did not differ significantly in the three groups. We have found that using a mydriatic cocktail-soaked wick - an alternative way to achieve intraoperative mydriasis for cataract surgery - was as effective and safe as the conventional repeated eyedrops regiment for tamsulosin treated patients. Current Controlled Trials ISRCTN37834752.

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.

Increased Angiotensin II Sensitivity Contributes to Microvascular Dysfunction in Women Who Have Had Preeclampsia.

PubMed

Stanhewicz, Anna E; Jandu, Sandeep; Santhanam, Lakshmi; Alexander, Lacy M

2017-08-01

Women who have had preeclampsia have increased cardiovascular disease risk; however, the mechanism(s) responsible for this association remain unclear. Microvascular damage sustained during a preeclamptic pregnancy may persist postpartum. The putative mechanisms mediating this dysfunction include a reduction in NO-dependent dilation and an increased sensitivity to angiotensin II. In this study, we evaluated endothelium-dependent dilation, angiotensin II sensitivity, and the therapeutic effect of angiotensin II receptor blockade (losartan) on endothelium-dependent dilation in vivo in the microvasculature of women with a history of preeclampsia (n=12) and control women who had a healthy pregnancy (n=12). We hypothesized that preeclampsia would have (1) reduced endothelium-dependent dilation, (2) reduced NO-mediated dilation, and (3) increased sensitivity to angiotensin II. We further hypothesized that localized losartan would increase endothelium-dependent vasodilation in preeclampsia. We assessed microvascular endothelium-dependent vasodilator function by measurement of cutaneous vascular conductance responses to graded infusion of acetylcholine (acetylcholine; 10 -7 -102 mmol/L) and a standardized local heating protocol in control sites and sites treated with 15 mmol/L L-NAME ( N G -nitro-l-arginine methyl ester; NO-synthase inhibitor) or 43 µmol/L losartan. Further, we assessed microvascular vasoconstrictor sensitivity to angiotensin II (10 -20 -10 -4 mol/L). Preeclampsia had significantly reduced endothelium-dependent dilation (-0.3±0.5 versus -1.0±0.4 log EC50 ; P <0.001) and NO-dependent dilation (16±3% versus 39±6%; P =0.006). Preeclampsia also had augmented vasoconstrictor sensitivity to angiotensin II (-10.2±1.3 versus -8.3±0.5; P =0.006). Angiotensin II type I receptor inhibition augmented endothelium-dependent vasodilation and NO-dependent dilation in preeclampsia but had no effect in healthy pregnancy. These data suggest that women who have had preeclampsia have persistent microvascular dysfunction postpartum, mediated, in part, by increased sensitivity to angiotensin II. © 2017 American Heart Association, Inc.

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

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

GRACE gravity data help constraining seismic models of the 2004 Sumatran earthquake

NASA Astrophysics Data System (ADS)

Cambiotti, G.; Bordoni, A.; Sabadini, R.; Colli, L.

2011-10-01

The analysis of Gravity Recovery and Climate Experiment (GRACE) Level 2 data time series from the Center for Space Research (CSR) and GeoForschungsZentrum (GFZ) allows us to extract a new estimate of the co-seismic gravity signal due to the 2004 Sumatran earthquake. Owing to compressible self-gravitating Earth models, including sea level feedback in a new self-consistent way and designed to compute gravitational perturbations due to volume changes separately, we are able to prove that the asymmetry in the co-seismic gravity pattern, in which the north-eastern negative anomaly is twice as large as the south-western positive anomaly, is not due to the previously overestimated dilatation in the crust. The overestimate was due to a large dilatation localized at the fault discontinuity, the gravitational effect of which is compensated by an opposite contribution from topography due to the uplifted crust. After this localized dilatation is removed, we instead predict compression in the footwall and dilatation in the hanging wall. The overall anomaly is then mainly due to the additional gravitational effects of the ocean after water is displaced away from the uplifted crust, as first indicated by de Linage et al. (2009). We also detail the differences between compressible and incompressible material properties. By focusing on the most robust estimates from GRACE data, consisting of the peak-to-peak gravity anomaly and an asymmetry coefficient, that is given by the ratio of the negative gravity anomaly over the positive anomaly, we show that they are quite sensitive to seismic source depths and dip angles. This allows us to exploit space gravity data for the first time to help constraining centroid-momentum-tensor (CMT) source analyses of the 2004 Sumatran earthquake and to conclude that the seismic moment has been released mainly in the lower crust rather than the lithospheric mantle. Thus, GRACE data and CMT source analyses, as well as geodetic slip distributions aided by GPS, complement each other for a robust inference of the seismic source of large earthquakes. Particular care is devoted to the spatial filtering of the gravity anomalies estimated both from observations and models to make their comparison significant.

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.

Is side-viewing endoscope assisted balloon dilatation better for corrosive gastric outlet obstruction?

PubMed

Katiyar, Prashant; Nijhawan, Sandeep; Saradava, Vimal; Nagaich, Neeraj; Gupta, Gaurav; Mathur, Amit; Nepalia, Subhash

2013-11-01

Endoscopic balloon dilatation (EBD) is an effective therapy for caustic-induced gastric outlet obstruction (GOO). Gaining access to the stricture site is the most important step. It is sometimes difficult to negotiate a balloon through the stricture with a front-viewing endoscope due to deformed anatomy of stomach. To overcome this technical difficulty, a side-viewing endoscope can be used. There is limited data regarding the use of side-viewing endoscopes in EBD. We here report on the short-term efficacy and safety of EBD in caustic-induced GOO. In technically difficult cases, a side-viewing endoscope was used for EBD and its efficacy and safety were assessed. The study included 25 patients with caustic-induced GOO. Patients underwent EBD using a through-the-scope balloon. Initial balloon dilatation was performed with a front-viewing endoscope. A side-viewing endoscope was used where negotiation across the stricture failed with a front-viewing endoscope. Dilatation was started at 8 mm diameter and was performed at 1-week intervals. The end point of dilatation was 15 mm diameter. In 18 patients successful balloon dilatation was possible with a front-viewing endoscope. A side-viewing endoscope was used in six patients as negotiation across the stricture was not possible with a front-viewing endoscope. In all six patients negotiation across the stricture followed by successful dilatation was successful with a side-viewing endoscope. Of the 25 patients included in this study, 24 (96%) achieved procedural success (18 with a front-viewing endoscope and 6 with a side-viewing endoscope) in 3-9 sessions. Our results show that EBD is a safe and effective option for caustic-induced GOO and in difficult cases a side-viewing endoscope can be used to achieve technical success.

Factors Affecting the Prevalence of Gastro-oesophageal Reflux in Childhood Corrosive Oesophageal Strictures.

PubMed

Iskit, Serdar H; Ozçelik, Zerrin; Alkan, Murat; Türker, Selcan; Zorludemir, Unal

2014-06-01

Gastro-oesophageal reflux may accompany the corrosive oesophageal damage caused by the ingestion of corrosive substances and affect its treatment. The factors that affect the development of reflux in these cases and their effects on treatment still remain unclear. Our aim is to investigate the prevalence of gastro-oesophageal reflux in children with corrosive oesophageal strictures, the risk factors affecting this prevalence and the effects of gastro-oesophageal reflux on treatment. Case-control study. We enrolled 52 patients with oesophageal stricture due to corrosive substance ingestion who were referred to our clinic between 2003 and 2010. Groups, which were determined according to the presence of gastro-oesophageal reflux (GER), were compared with each other in terms of clinical findings, results of examination methods, characteristics of the stricture and success of the treatment. The total number of patients in our study was 52; 30 of them were male and 22 of them were female. The mean age of our study population was 4.2±2.88 years. Thirty-three patients had gastrooesophageal reflux (63.5%). Patients who had strictures caused by the ingestion of alkali substances were 1.6-times more likely to have reflux. There were no differences between patients with or without reflux in terms of number and localisation of strictures. Mean distance of stricture was longer in patients with reflux (3.7±1.8 cm) than in patients without (2.2±1.0 cm) (p<0.005). Only one patient among 17 who had a long stricture (≥4 cm) did not suffer from reflux. Patients with long stricture were 1.9-times more likely to have reflux. Dilatation treatment was successful in 69.6% of patients with reflux and in 78.9% of patients without. The mean treatment period was 8.41±6.1 months in patients with reflux and 8.21±8.4 months in the other group. There was no significant difference between groups in terms of frequency of dilatation and dilator diameters (p>0.05). Corrosive oesophageal stricture was usually accompanied by gastro-oesophageal reflux and the length of stricture is an important risk factor. Negative effects of reflux over dilatation treatment have not yet been demonstrated in the short-term. Nevertheless, this frequent rate of reflux may eventually increase the risk of oesophagitis and Barrett's oesophagus; therefore, we suggest that these effects should be prospectively evaluated in a large number of patients and these patients should be followed-up routinely in terms of the long-term effects of reflux.

Oxytocin enhances pupil dilation and sensitivity to ‘hidden’ emotional expressions

PubMed Central

Wessberg, Johan; Ellingsen, Dan-Mikael; Chelnokova, Olga; Olausson, Håkan; Laeng, Bruno

2013-01-01

Sensing others’ emotions through subtle facial expressions is a highly important social skill. We investigated the effects of intranasal oxytocin treatment on the evaluation of explicit and ‘hidden’ emotional expressions and related the results to individual differences in sensitivity to others’ subtle expressions of anger and happiness. Forty healthy volunteers participated in this double-blind, placebo-controlled crossover study, which shows that a single dose of intranasal oxytocin (40 IU) enhanced or ‘sharpened’ evaluative processing of others’ positive and negative facial expression for both explicit and hidden emotional information. Our results point to mechanisms that could underpin oxytocin’s prosocial effects in humans. Importantly, individual differences in baseline emotional sensitivity predicted oxytocin’s effects on the ability to sense differences between faces with hidden emotional information. Participants with low emotional sensitivity showed greater oxytocin-induced improvement. These participants also showed larger task-related pupil dilation, suggesting that they also allocated the most attentional resources to the task. Overall, oxytocin treatment enhanced stimulus-induced pupil dilation, consistent with oxytocin enhancement of attention towards socially relevant stimuli. Since pupil dilation can be associated with increased attractiveness and approach behaviour, this effect could also represent a mechanism by which oxytocin increases human affiliation. PMID:22648957

Oxytocin enhances pupil dilation and sensitivity to 'hidden' emotional expressions.

PubMed

Leknes, Siri; Wessberg, Johan; Ellingsen, Dan-Mikael; Chelnokova, Olga; Olausson, Håkan; Laeng, Bruno

2013-10-01

Sensing others' emotions through subtle facial expressions is a highly important social skill. We investigated the effects of intranasal oxytocin treatment on the evaluation of explicit and 'hidden' emotional expressions and related the results to individual differences in sensitivity to others' subtle expressions of anger and happiness. Forty healthy volunteers participated in this double-blind, placebo-controlled crossover study, which shows that a single dose of intranasal oxytocin (40 IU) enhanced or 'sharpened' evaluative processing of others' positive and negative facial expression for both explicit and hidden emotional information. Our results point to mechanisms that could underpin oxytocin's prosocial effects in humans. Importantly, individual differences in baseline emotional sensitivity predicted oxytocin's effects on the ability to sense differences between faces with hidden emotional information. Participants with low emotional sensitivity showed greater oxytocin-induced improvement. These participants also showed larger task-related pupil dilation, suggesting that they also allocated the most attentional resources to the task. Overall, oxytocin treatment enhanced stimulus-induced pupil dilation, consistent with oxytocin enhancement of attention towards socially relevant stimuli. Since pupil dilation can be associated with increased attractiveness and approach behaviour, this effect could also represent a mechanism by which oxytocin increases human affiliation.

Photochemical effects in the lens from near infrared radiation?

NASA Astrophysics Data System (ADS)

Söderberg, Per G.; Al-Saqry, Riyadh; Schulmeister, Karl; Gallichanin, Konstantin; Kronschläger, Martin; Yu, Zhaohua

2009-02-01

Conclusion: The current data are consistent with a potential photochemical effect of in vivo exposure of the crystalline lens to near infrared radiation since the onset of cataract after in just above threshold dose was at least 18 hrs delayed after the exposure. Materials and methods: The eyes of 6 weeks old Sprague-Dawley rats were exposed unilaterally in vivo to 1090 nm, 6.2 W quasi-top hat spatial distribution with a 3 mm spot on the anterior lens surface within the dilated pupil. First, four exposure time groups of rats were exposed to increasing exposure times. At 24 hrs after exposure, the difference of light scattering between the lenses from the same animal was measured. Then, based on the first experiment, four post-exposure time groups were exposed unilaterally in vivo to 8 s of 1090 nm, 6.2 W quasi-top hat spatial distribution with a 3 mm spot on the anterior lens surface within the dilated pupil. After, the intended post-exposure time, the difference of light scattering between the lenses from the same animal was measured. Results: A 3 mm spot of 6.2 W induces light scattering in the lens with exposures of at least 8 s. Further, after 8 s of 6.2 W within a 3 mm spot on the lens surface, the light scattering increase in the lens was delayed at least 18 hrs after the exposure.

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.

Conservation of ζ with radiative corrections from heavy field

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

Tanaka, Takahiro; Yukawa Institute for Theoretical Physics, Kyoto University,Kyoto, 606-8502; Urakawa, Yuko

2016-06-08

In this paper, we address a possible impact of radiative corrections from a heavy scalar field χ on the curvature perturbation ζ. Integrating out χ, we derive the effective action for ζ, which includes the loop corrections of the heavy field χ. When the mass of χ is much larger than the Hubble scale H, the loop corrections of χ only yield a local contribution to the effective action and hence the effective action simply gives an action for ζ in a single field model, where, as is widely known, ζ is conserved in time after the Hubble crossing time.more » Meanwhile, when the mass of χ is comparable to H, the loop corrections of χ can give a non-local contribution to the effective action. Because of the non-local contribution from χ, in general, ζ may not be conserved, even if the classical background trajectory is determined only by the evolution of the inflaton. In this paper, we derive the condition that ζ is conserved in time in the presence of the radiative corrections from χ. Namely, we show that when the dilatation invariance, which is a part of the diffeomorphism invariance, is preserved at the quantum level, the loop corrections of the massive field χ do not disturb the constant evolution of ζ at super Hubble scales. In this discussion, we show the Ward-Takahashi identity for the dilatation invariance, which yields a consistency relation for the correlation functions of the massive field χ.« less

Implementation into earthquake sequence simulations of a rate- and state-dependent friction law incorporating pressure solution creep

NASA Astrophysics Data System (ADS)

Noda, H.

2016-05-01

Pressure solution creep (PSC) is an important elementary process in rock friction at high temperatures where solubilities of rock-forming minerals are significantly large. It significantly changes the frictional resistance and enhances time-dependent strengthening. A recent microphysical model for PSC-involved friction of clay-quartz mixtures, which can explain a transition between dilatant and non-dilatant deformation (d-nd transition), was modified here and implemented in dynamic earthquake sequence simulations. The original model resulted in essentially a kind of rate- and state-dependent friction (RSF) law, but assumed a constant friction coefficient for clay resulting in zero instantaneous rate dependency in the dilatant regime. In this study, an instantaneous rate dependency for the clay friction coefficient was introduced, consistent with experiments, resulting in a friction law suitable for earthquake sequence simulations. In addition, a term for time-dependent strengthening due to PSC was added which makes the friction law logarithmically rate-weakening in the dilatant regime. The width of the zone in which clasts overlap or, equivalently, the interface porosity involved in PSC plays a role as the state variable. Such a concrete physical meaning of the state variable is a great advantage in future modelling studies incorporating other physical processes such as hydraulic effects. Earthquake sequence simulations with different pore pressure distributions demonstrated that excess pore pressure at depth causes deeper rupture propagation with smaller slip per event and a shorter recurrence interval. The simulated ruptures were arrested a few kilometres below the point of pre-seismic peak stress at the d-nd transition and did not propagate spontaneously into the region of pre-seismic non-dilatant deformation. PSC weakens the fault against slow deformation and thus such a region cannot produce a dynamic stress drop. Dynamic rupture propagation further down to brittle-plastic transition, evidenced by geological observations, would require even smaller frictional resistance at coseismic slip rate, suggesting the importance of implementation of dynamic weakening activated at coseismic slip rates for more realistic simulation of earthquake sequences. The present models produced much smaller afterslip at deeper parts of arrested ruptures than those with logarithmic RSF laws because of a more significant rate-strengthening effect due to linearly viscous PSC. Detailed investigation of afterslip would give a clue to understand the deformation mechanism which controls shear resistance of the fault in a region of arrest of earthquake ruptures.

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

Exaggerated cardiovascular effects of cocaine in conscious dogs with pacing-induced dilated cardiomyopathy.

PubMed

Mathier, Michael A; Shen, You-Tang; Shannon, Richard P

2002-12-01

The aim of this study was to explore the characteristics and mechanisms of the cardiovascular effects of cocaine in dilated cardiomyopathy. We studied the cardiovascular responses to acute intravenous cocaine (1 mg/kg) in 8 conscious, chronically instrumented dogs before and after the development of dilated cardiomyopathy induced by rapid ventricular pacing. To help elucidate the role of altered baroreflex function in mediating the cardiovascular effects of cocaine, we also studied responses in 3 conscious, chronically instrumented dogs that had undergone surgical sinoaortic baroreceptor denervation. Cocaine produced greater increases in heart rate (+57 +/- 8% from 112 +/- 5 beats/min versus +28 +/- 3% from 100 +/- 4 beats/min; P <.01), first derivative of left ventricular pressure (+30 +/- 5% from 1,714 +/- 147 mm Hg/sec versus +15 +/- 3% from 3,032 +/- 199 mm Hg/sec; P <.01), coronary vascular resistance (+28 +/- 5% from 2.3 +/- 0.3 mm Hg/mL/min versus +11 +/- 5% from 2.2 +/- 0.3 mm Hg/mL/min; P <.05) and plasma norepinephrine concentration (+130 +/- 31% from 462 +/- 102 pg/mL versus +86 +/- 32% from 286 +/- 77 pg/mL; P <.05) in dogs with dilated cardiomyopathy as compared to controls. In addition, responses were much more rapid in onset following the development of dilated cardiomyopathy. Chronotropic and inotropic responses to cocaine were similarly rapid and exaggerated in dogs after baroreceptor denervation. Cocaine produces rapid and exaggerated chronotropic, inotropic, and coronary vasoconstrictor responses in conscious dogs with pacing-induced dilated cardiomyopathy. Alterations in arterial baroreflex function may play a role in these observations, which in turn may underlie the clinically observed association between cocaine and heart failure.

Acute increases in intraluminal pressure improve vasodilator responses in aged soleus muscle feed arteries.

PubMed

Seawright, John W; Luttrell, Meredith J; Woodman, Christopher R

2014-10-01

We tested the hypothesis that exposure to an acute increase in intraluminal pressure, to mimic pressure associated with a bout of exercise, improves nitric oxide (NO)-mediated endothelium-dependent dilation in aged soleus muscle feed arteries (SFA) and that improved endothelial function would persist after a 2 h recovery period. SFA from young (4-month) and old (24-month) Fischer 344 rats were cannulated and pressurized at 90 (P90) or 130 (P130) cmH2O for 60 min. At the end of the treatment period, pressure in the P130 SFA was lowered to 90 cmH2O for examination of endothelium-dependent [flow or acetylcholine (ACh)] and endothelium-independent [sodium nitroprusside (SNP)] vasodilation. To determine the role of NO, vasodilator responses were assessed in the presence of N (ω)-nitro-L-arginine (L-NNA). To determine whether the effects of pressure persisted following a recovery period at normal pressure, SFA were pressurized to 130 cmH2O for 60 min and subsequently lowered to 90 cmH2O for 2 h before assessing function. ACh- and flow-induced dilations were impaired in old SFA. Treatment with increased pressure for 60 min improved ACh- and flow-induced dilations in old SFA. SNP-induced dilation was improved in old and young SFA. The beneficial effect of pressure treatment on ACh- and flow-induced dilation in old SFA was blocked by L-NNA and was not present following a 2 h recovery period. These results indicate that an acute increase in intraluminal pressure improves NO-mediated endothelium-dependent dilation in aged SFA; however, the beneficial effect does not persist after 2 h.

Effects of aromatherapy with Rosa damascena on nulliparous women's pain and anxiety of labor during first stage of labor.

PubMed

Hamdamian, Sepideh; Nazarpour, Soheila; Simbar, Masoumeh; Hajian, Sepideh; Mojab, Faraz; Talebi, Atefeh

2018-03-01

Reducing labor pain and anxiety is one of the most important goals of maternity care. This study aimed to assess the effects of aromatherapy with Rosa damascena on pain and anxiety in the first stage of labor among nulliparous women. This was a randomized clinical trial of 110 nulliparous women. The eligible participants were randomly assigned to two groups of aromatherapy and control in an Iranian maternity hospital. The participants received 0.08 mL of Rosa damascena essence in the aromatherapy group and 0.08 mL of normal saline in the control group, every 30 min. Pain was measured 3 times, once each at three stages of cervical dilation (4-5, 6-7, and 8-10 cm). Anxiety was measured twice, once each at two stages of cervical dilation (4-7 and 8-10 cm). The tools for data collection were the Spielberger anxiety questionnaire, numerical pain rating scale, demographic and obstetric questionnaire, and an observational checklist. Data analyses included the t-test, Mann-Whitney U test and Chi-square test. Severity of labor pain and severity of anxiety were used as primary outcome measures. Labor and delivery characteristics (including number of contractions, duration of contractions in second stage, Bishop score, augmentation by oxytocin, Apgar score, and mode of delivery), demographic characteristics, and fertility information were used as secondary outcome measures. Pain severity in the group receiving aromatherapy with R. damascena was significantly lower than in the control group after treatment at each pain assessment (cervical dilation of 4-5, 6-7, and 8-10 cm; P < 0.05). Anxiety levels were also significantly lower in the treatment group than in the control group after treatment at each time of measurement (cervical dilation of 4-7 and 8-10 cm; P < 0.05). Aromatherapy with R. damascena reduced the severity of pain and anxiety in the first stage of labor. Aromatherapy with R. damascena is a convenient and effective method for pain and anxiety reduction during the first stage of labor. Iranian Registry of Clinical Trial: IRCT201306258801N3. Copyright © 2018 Shanghai Changhai Hospital. Published by Elsevier B.V. All rights reserved.

Pupil-mimicry conditions trust in partners: moderation by oxytocin and group membership

PubMed Central

De Dreu, Carsten K. W.

2017-01-01

Across species, oxytocin, an evolutionarily ancient neuropeptide, facilitates social communication by attuning individuals to conspecifics' social signals, fostering trust and bonding. The eyes have an important signalling function; and humans use their salient and communicative eyes to intentionally and unintentionally send social signals to others, by contracting the muscles around their eyes and pupils. In our earlier research, we observed that interaction partners with dilating pupils are trusted more than partners with constricting pupils. But over and beyond this effect, we found that the pupil sizes of partners synchronize and that when pupils synchronously dilate, trust is further boosted. Critically, this linkage between mimicry and trust was bound to interactions between ingroup members. The current study investigates whether these findings are modulated by oxytocin and sex of participant and partner. Using incentivized trust games with partners from ingroup and outgroup whose pupils dilated, remained static or constricted, this study replicates our earlier findings. It further reveals that (i) male participants withhold trust from partners with constricting pupils and extend trust to partners with dilating pupils, especially when given oxytocin rather than placebo; (ii) female participants trust partners with dilating pupils most, but this effect is blunted under oxytocin; (iii) under oxytocin rather than placebo, pupil dilation mimicry is weaker and pupil constriction mimicry stronger; and (iv) the link between pupil constriction mimicry and distrust observed under placebo disappears under oxytocin. We suggest that pupil-contingent trust is parochial and evolved in social species in and because of group life. PMID:28250181

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.

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.

Plastic Biliary Stent Migration During Multiple Stents Placement and Successful Endoscopic Removal Using Intra-Stent Balloon Inflation Technique: A Case Report and Literature Review.

PubMed

Calcara, Calcedonio; Broglia, Laura; Comi, Giovanni; Balzarini, Marco

2016-02-05

Late migration of a plastic biliary stent after endoscopic placement is a well known complication, but there is little information regarding migration of a plastic stent during multiple stents placement. A white man was hospitalized for severe jaundice due to neoplastic hilar stenosis. Surgical eligibility appeared unclear on admission and endoscopy was carried out, but the first stent migrated proximally at the time of second stent insertion. After failed attempts with various devices, the migrated stent was removed successfully through cannulation with a dilation balloon. The migration of a plastic biliary stent during multiple stents placement is a possible complication. In this context, extraction can be very complicated. In our patient, cannulation of a stent with a dilation balloon was the only effective method.

Exercise training improves endothelial function in young prehypertensives

PubMed Central

Beck, Darren T; Casey, Darren P; Martin, Jeffrey S; Emerson, Blaze D; Braith, Randy W

2015-01-01

Prehypertensives exhibit marked endothelial dysfunction, a risk factor for future cardiovascular morbidity and mortality. However, the ability of exercise to ameliorate endothelial dysfunction in prehypertensives is grossly underinvestigated. This prospective randomized and controlled study examined the separate effects of resistance and endurance training on conduit artery endothelial function in young prehypertensives. Forty-three unmedicated prehypertensive (systolic blood pressure [SBP]=120–139 mmHg; diastolic blood pressure [DBP]=80–89 mmHg) but otherwise healthy men and women and 15 normotensive matched time-controls (NMTC); n = 15) between 18 and 35 y of age met screening requirements and participated in the study. Prehypertensive subjects were randomly assigned to either a resistance exercise training (PHRT; n = 15), endurance exercise training (PHET; n = 13) or time-control group (PHTC; n = 15). The treatment groups performed exercise training three days per week for eight weeks. The control groups did not initiate exercise programs throughout the study. Flow mediated dilation (FMD) of the brachial artery, biomarkers of enodothelial function and peripheral blood pressure were evaluated before and after exercise intervention or time-matched control. PHRT and PHET reduced resting SBP (9.6 ± 3.6 and 11.9 ± 3.4 mmHg, respectively; P < 0.05) and DBP (8.0 ± 5.1 and 7.2 ± 3.4 mmHg, respectively; P < 0.05). Exercise training improved brachial artery FMD absolute diameter, percent dilation and normalized percent dilation by 30%, 34% and 19% for PHRT, P < 0.05; and by 54%, 63% and 75% for PHET, P < 0.05; respectively. PHRT and PHET increased plasma concentrations of 6-keto prostaglandin F1α (19% and 22%, respectively; P < 0.05), NOx (19% and 23%, respectively; P < 0.05), and reduced endothelin-1 by (16% and 24%, respectively; P < 0.01). This study provides novel evidence that resistance and endurance exercise separately have beneficial effects on resting peripheral blood pressure, brachial artery FMD and endothelial-derived vasoactive agents in young prehypertensives. PMID:23760009

A clinical comparison of cordless and conventional displacement systems regarding clinical performance and impression quality.

PubMed

Acar, Özlem; Erkut, Selim; Özçelik, Tuncer Burak; Ozdemır, Erdem; Akçil, Mehtap

2014-05-01

It is not clear whether newly introduced cordless displacement systems are better able to manage gingiva than conventional systems. The purpose of this in vivo study was to evaluate the gingival management ability of 4 different displacement methods with a standardized subgingival preparation finish line. The effects of 4 displacement techniques on gingival management and impression quality were evaluated by means of 6 evaluation criteria. A subgingival preparation finish line of between 1 and 2 mm was ensured, and the buccal aspects of 252 (n=63) teeth were clinically assessed for ease of application, time spent, bleeding, remnants, and dilatation. The complete reproduction of the preparation finish line and the bubble and void formations on polyether impressions were also evaluated. The data were statistically analyzed with the χ(2) test (α=.05). The Bonferroni correction was used to control Type I error for the pairwise comparison groups (α=.008). Statistically significant differences were found for all criteria among the groups (P<.05). The nonimpregnated displacement cord group was the least effective group in terms of bleeding and impression quality (P<.008). The aluminum chloride impregnated cord group and the displacement paste with cap group were found to be comparable in terms of remnants, dilatation, and impression quality (P>.008). The retraction cap with paste group showed better results for ease of application, time spent, and bleeding than the aluminum chloride impregnated cord group (P<.008). Although the group with aluminum chloride impregnated cord, displacement paste, and cap showed better results for dilatation, it was time consuming and difficult (P<.008). Except for the nonimpregnated cord group, all of the groups were comparable and clinically useful, with perfect or acceptable impression qualities. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

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.

Can A "Hyperspace" Really Exist?

NASA Technical Reports Server (NTRS)

Zampino, Edward J.

1999-01-01

The idea of "hyperspace" is suggested as a possible approach to faster-than-light (FTL) motion. A brief summary of a 1986 study on the Euclidean representation of space-time by the author is presented. Some new calculations on the relativistic momentum and energy of a free particle in Euclidean "hyperspace" are now added and discussed. The superimposed Energy-Momentum curves for subluminal particles, tachyons, and particles in Euclidean "hyperspace" are presented. It is shown that in Euclidean "hyperspace", instead of a relativistic time dilation there is a time "compression" effect. Some fundamental questions are presented,

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.

Dilatant effect enhancers for silica dispersions in poly(propylene glycols).

PubMed

Orawiec, Marcin; Kaczorowski, Marcin; Rokicki, Gabriel

2018-05-29

Shear thickening fluids have found many applications in energy damping materials such as sports guards and liquid body armors. Therefore, an additive which could tailor the dilatant properties of such fluids without significantly affecting other properties, especially zero shear viscosity, could significantly increase the versatility of protective materials based on shear thickening fluids. In this paper, poly(propylene glycols) (PPGs) diacetates are investigated as dilatant effect enhancers for nano-silica dispersions in poly(propylene glycols). The influence of the modifiers on rheological properties of the dispersion is studied and discussed. Additionally, FTIR and rheological properties measurements are conducted in order to determine relative interactions strength between hydroxyl groups of PPGs and silica and carbonyl groups of PPG diacetates. Our findings suggest that the relative attractive interaction strength in studied systems can be arranged in the following order: COCO < COOH < OHOH. Therefore, the addition of PPG diacetate hinders the attractive interactions between liquid and solid. We report that the addition of diacetates can lead both to enhancement and deterioration of dilatant effect depending on the concentration of the modifier and its chain length. Based on conducted measurements and literature data, mechanism explaining that phenomenon is suggested. As a result, we propose an easy to make and cheap dilatant effect enhancer for widely used shear thickening fluids which, when used in small amounts (1-2.5%), raises the viscosity jump drastically. Additionally, the presence of the modifier does not significantly affect the zero shear viscosity of the shear thickening fluid. Copyright © 2018 Elsevier Inc. All rights reserved.

Mitochondrial dysfunction in myocardium obtained from clinically normal dogs, clinically normal anesthetized dogs, and dogs with dilated cardiomyopathy.

PubMed

Sleeper, Meg M; Rosato, Bradley P; Bansal, Seema; Avadhani, Narayan G

2012-11-01

To compare mitochondrial complex I and complex IV activity in myocardial mitochondria of clinically normal dogs, clinically normal dogs exposed to inhalation anesthesia, and dogs affected with dilated cardiomyopathy. Myocardial samples obtained from 21 euthanized dogs (6 clinically normal [control] dogs, 5 clinically normal dogs subjected to inhalation anesthesia with isoflurane prior to euthanasia, 5 dogs with juvenile-onset dilated cardiomyopathy, and 5 dogs with adult-onset dilated cardiomyopathy). Activity of mitochondrial complex I and complex IV was assayed spectrophotometrically in isolated mitochondria from left ventricular tissue obtained from the 4 groups of dogs. Activity of complex I and complex IV was significantly decreased in anesthetized dogs, compared with activities in the control dogs and dogs with juvenile-onset or adult-onset dilated cardiomyopathy. Inhalation anesthesia disrupted the electron transport chain in the dogs, which potentially led to an outburst of reactive oxygen species that caused mitochondrial dysfunction. Inhalation anesthesia depressed mitochondrial function in dogs, similar to results reported in other species. This effect is important to consider when anesthetizing animals with myocardial disease and suggested that antioxidant treatments may be beneficial in some animals. Additionally, this effect should be considered when designing studies in which mitochondrial enzyme activity will be measured. Additional studies that include a larger number of animals are warranted.

Endoscopy-guided balloon dilation of benign anastomotic strictures after radical gastrectomy for gastric cancer.

PubMed

Lee, Hyun Jik; Park, Wan; Lee, Hyuk; Lee, Keun Ho; Park, Jun Chul; Shin, Sung Kwan; Lee, Sang Kil; Lee, Yong Chan; Noh, Sung Hoon

2014-07-01

The aim of this study was to evaluate the outcome of endoscopic dilation for benign anastomotic stricture after radical gastrectomy in gastric cancer patients. Gastric cancer patients who underwent endoscopic balloon dilation for benign anastomosis stricture after radical gastrectomy during a 6-year period were reviewed retrospectively. Twenty-one patients developed benign strictures at the site of anastomosis. The majority of strictures occurred within 1 year after surgery (95.2%). The median duration to stenosis after surgery was 1.70 months (range, 0.17 to 23.97 months). The success rate of the first endoscopic dilation was 61.9%. Between the restenosis group (n=8) and the no restenosis group (n=13), there were no significant differences in the body mass index (22.82 kg/m(2) vs 22.46 kg/m(2)), interval to symptom onset (73.9 days vs 109.3 days), interval to treatment (84.6 days vs 115.6 days), maximal balloon diameter (14.12 mm vs 15.62 mm), number of balloon dilation sessions (1.75 vs 1.31), location of gastric cancer or type of surgery. One patient required surgery because of stricture refractory to repeated dilation. Endoscopic dilation is a highly effective treatment for benign anastomotic strictures after radical gastrectomy for gastric cancer and should be considered a primary intervention prior to proceeding with surgical revision.

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.

Simple urethral dilatation, endoscopic urethrotomy, and urethroplasty for urethral stricture disease in adult men.

PubMed

Wong, Susan S W; Narahari, Radhakrishna; O'Riordan, Anna; Pickard, Robert

2010-04-14

Strictures of the urethra are the commonest cause of obstructed micturition in younger men and frequently recur after initial treatment. Standard treatment comprises internal widening of the strictured area by simple dilatation or by telescope-guided internal cutting (optical urethrotomy), but these interventions are associated with a high failure rate requiring repeated treatment. The alternative option of open urethroplasty whereby the urethral lumen is permanently widened by removal or grafting of the strictured segment is less likely to fail but requires greater expertise. Improved choice of graft material and shortened hospital stay suggest urethroplasty may be under used. The extent and quality of evidence guiding treatment choice for this condition is uncertain. To determine which is the best surgical treatment for male urethral stricture disease taking into account relative efficacy, adverse event rates and cost-effectiveness. We searched the Cochrane Incontinence Group Specialised Register (searched 26 March 2009), CENTRAL (2009, Issue 1), MEDLINE (January 1950 to March 2009), EMBASE (January 1980 to March 2009), OpenSIGLE (searched 26 March 2009), clinical trials registries and reference lists of relevant articles. We included publications reporting data from randomised or quasi-randomised controlled trials comparing the effectiveness of dilatation, urethrotomy and urethroplasty in the treatment of adult men with urethral stricture disease. Two authors evaluated trials for appropriateness for inclusion and methodological quality. Data extraction was performed using predetermined criteria. Analyses were carried out using the Cochrane Review Manager software; RevMan 5. Two randomised trials were identified. One trial compared the outcome of surgical urethral dilatation and optical urethrotomy in 210 adult men with urethral stricture disease. No significant difference was found in the proportion of men being stricture free at three years or in the median time to recurrence. The second trial compared the outcome of urethrotomy and urethroplasty in 50 men with traumatic stricture of the posterior urethra following pelvic fracture injury. After two years 16 of 25 (64%) men initially treated by urethrotomy required continued self-dilatation or further surgery for stricture recurrence compared to 6 of 25 (24%) men treated by primary urethroplasty. There was insufficient data to perform meta-analysis or to reliably determine effect size. There were insufficient data to determine which intervention is best for urethral stricture disease in terms of balancing efficacy, adverse effects and costs. Well designed, adequately powered multi-centre trials are needed to answer relevant clinical questions regarding treatment of men with urethral strictures.

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.

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.

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

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.

[Tissue expansion under the cicatrix].

PubMed

Cai, Guo-Bin; Liu, Liu; Li, Tai-Ying; Zhang, Yi; Wang, Chun-Mei

2005-09-01

To investigate a more simple and effective method to repair cicatrix by tissue expansion. The dilator with the capacity of 80 - 500 ml was implanted into the subcutaneous pocket under the cicatrix. After dilating for one to two months, the dilator was taken out and the wound surface of the cicatrix was removed. The expanded skin flap was advanced or rotated to cover the defects. The procedure was used on 203 cases. The dilatation was achieved successfully in all the cases, followed by cicatrix removing and repair. The incision scar was not noticeable. Tissue expansion under the cicatrix has the advantages of safety, less trauma and less extra incisions. It is a reasonable choice to obtain more flexible surgical designs and more economical skin flap applications. It is suitable for most of the treatment for cicatrix.

Noise transmission by viscoelastic sandwich panels

NASA Technical Reports Server (NTRS)

Vaicaitis, R.

1977-01-01

An analytical study on low frequency noise transmission into rectangular enclosures by viscoelastic sandwich panels is presented. Soft compressible cores with dilatational modes and hard incompressible cores with dilatational modes neglected are considered as limiting cases of core stiffness. It is reported that these panels can effect significant noise reduction.

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.

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

Mach's Principle to Hubble's Law and Light Relativity

NASA Astrophysics Data System (ADS)

Zhang, Tianxi

2018-01-01

Discovery of the redshift-distance relation to be linear (i.e. Hubble's law) for galaxies in the end of 1920s instigated us to widely accept expansion of the universe, originated from a big bang around 14 billion years ago. Finding of the redshift-distance relation to be weaker than linear for distant type Ia supernovae nearly two decades ago further precipitated us to largely agree with recent acceleration of the universe, driven by the mysterious dark energy. The time dilation measured for supernovae has been claimed as a direct evidence for the expansion of the universe, but scientists could not explain why quasars and gamma-ray bursts had not similar time dilations. Recently, an anomaly was found in the standard template for the width of supernova light curves to be proportional to the wavelength, which exactly removed the time dilation of supernovae and hence was strongly inconsistent with the conventional redshift mechanism. In this study, we have derived a new redshift-distance relation from Mach's principle with light relativity that describes the effect of light on spacetime as well as the influence of disturbed spacetime on the light inertia or frequency. A moving object or photon, because of its continuously keeping on displacement, disturbs the rest of the entire universe or distorts/curves the spacetime. The distorted or curved spacetime then generates an effective gravitational force to act back on the moving object or photon, so that reduces the object inertia or photon frequency. Considering the disturbance of spacetime by a photon is extremely weak, we have modelled the effective gravitational force to be Newtonian and derived the new redshift-distance relation that can not only perfectly explain the redshift-distance measurement of distant type Ia supernovae but also inherently obtain Hubble's law as an approximate at small redshift. Therefore, the result obtained from this study does neither support the acceleration of the universe nor the expansion of the universe but prefers to Einstein's simplest cosmology of the static universe or Zhang's static or dynamic cosmology of the black hole universe. This work was partially supported by NSF/REU (Grant #: PHY-1559870) at Alabama A & M University

Flicker-induced retinal arteriole dilation is reduced by ambient lighting.

PubMed

Noonan, Jonathan E; Dusting, Gregory J; Nguyen, Thanh T; Man, Ryan E K; Best, William J; Lamoureux, Ecosse L

2014-08-07

To investigate the impact of ambient room lighting on the magnitude of flicker light-induced retinal vasodilations in healthy individuals. Twenty healthy nonsmokers participated in a balanced 2 × 2 crossover study. Retinal vascular imaging was performed with the dynamic vessel analyzer under reduced or normal ambient lighting, then again after 20 minutes under the alternate condition. Baseline calibers of selected arteriole and venule segments were recorded in measurement units. Maximum percentage dilations from baseline during 20 seconds of luminance flicker were calculated from the mean of three measurement cycles. Within-subject differences were assessed by repeated measures analysis of variance with the assumption of no carryover effects and pairwise comparisons from the fitted model. Mean (SD) maximum arteriole dilations during flicker stimulation under reduced and normal ambient lighting were 4.8% (2.3%) and 4.1% (1.9%), respectively (P = 0.019). Maximum arteriole dilations were (mean ± 95% confidence interval) 0.7% ± 0.6% lower under normal ambient lighting compared with reduced lighting. Ambient lighting had no significant effect on maximum venular dilations during flicker stimulation or on the baseline calibers of arterioles or venules. Retinal arteriole dilation in response to luminance flicker stimulation is reduced under higher ambient lighting conditions. Reduced responses with higher ambient lighting may reflect reduced contrast between the ON and OFF flicker phases. Although it may not always be feasible to conduct studies under reduced lighting conditions, ambient lighting levels should be consistent to ensure that comparisons are valid. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

Pupil-mimicry conditions trust in partners: moderation by oxytocin and group membership.

PubMed

Kret, Mariska E; De Dreu, Carsten K W

2017-03-15

Across species, oxytocin, an evolutionarily ancient neuropeptide, facilitates social communication by attuning individuals to conspecifics' social signals, fostering trust and bonding. The eyes have an important signalling function; and humans use their salient and communicative eyes to intentionally and unintentionally send social signals to others, by contracting the muscles around their eyes and pupils. In our earlier research, we observed that interaction partners with dilating pupils are trusted more than partners with constricting pupils. But over and beyond this effect, we found that the pupil sizes of partners synchronize and that when pupils synchronously dilate, trust is further boosted. Critically, this linkage between mimicry and trust was bound to interactions between ingroup members. The current study investigates whether these findings are modulated by oxytocin and sex of participant and partner. Using incentivized trust games with partners from ingroup and outgroup whose pupils dilated, remained static or constricted, this study replicates our earlier findings. It further reveals that (i) male participants withhold trust from partners with constricting pupils and extend trust to partners with dilating pupils, especially when given oxytocin rather than placebo; (ii) female participants trust partners with dilating pupils most, but this effect is blunted under oxytocin; (iii) under oxytocin rather than placebo, pupil dilation mimicry is weaker and pupil constriction mimicry stronger; and (iv) the link between pupil constriction mimicry and distrust observed under placebo disappears under oxytocin. We suggest that pupil-contingent trust is parochial and evolved in social species in and because of group life. © 2017 The Authors.

Effect of intracoronary nitroprusside injection on flow recovery during primary PCI in acute STEMI patients.

PubMed

Yang, Lixia; Mu, Lihua; Sun, Linhui; Qi, Feng; Guo, Ruiwei

2017-04-01

The no/slow reflow phenomenon during primary percutaneous coronary intervention (PPCI) causes the destruction of the coronary microcirculation and further myocardial damage. Some studies have shown that intracoronary nitroprusside infusion is a safe and effective method for managing the no/slow reflow phenomenon. However, it is uncertain whether the injection of nitroprusside at a specific time point during PPCI can most effectively prevent no-reflow. In this study, we investigated the effect of the timing of an intracoronary nitroprusside injection on flow recovery during PPCI in patients with ST elevation acute myocardial infarction (STEMI). One hundred twenty consecutive patients with STEMI who underwent PPCI were enrolled in the study. Patients who fulfilled the eligibility criteria were randomly allocated to three groups: control group (N.=40) received no nitroprusside before they completed PCI; the second group (N.=40) received nitroprusside before balloon dilatation; and the third group (N.=40) received nitroprusside after each balloon dilatation and before contrast agent refilling. The baseline clinical variables and the details of the PCI procedure were collected. The thrombolysis in myocardial infarction (TIMI) flow grades and the corrected TIMI frame count (cTFC) were evaluated immediately after stent implantation was completed. There were no significant differences in the baseline characteristics, antithrombotic drugs given before PCI, and details of the PCI procedure among the three groups (P>0.05). The incidence of TIMI grade 3 after PCI was significantly higher in the nitroprusside group than in the control group (P=0.025), whereas cTFC was significantly lower in the nitroprusside group (26.6±15.2) than in the control group (38.1±21.3, P=0.001). The incidence of TIMI grade 3 after PCI was significantly higher in the third group than in the second group (P=0.045), and cTFC was significantly lower in the third group (21.5±9.5) than in the second group (31.2±18.3, P=0.002). Multivariable linear regression analyses showed that the intracoronary nitroprusside injection time was a significant predictor of cTFC after PCI. These data suggest that the intracoronary injection of nitroprusside significantly reduced the incidence of no/slow reflow during PPCI. The intracoronary injection of nitroprusside most effectively prevented the no/slow reflow phenomenon when administered between balloon dilatation and contrast agent refilling during PPCI.

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.

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

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.

Associated Information Increases Subjective Perception of Duration.

PubMed

Schweitzer, Richard; Trapp, Sabrina; Bar, Moshe

2017-08-01

Our sense of time is prone to various biases. For instance, one factor that can dilate an event's perceived duration is the violation of predictions; when a series of repeated stimuli is interrupted by an unpredictable oddball. On the other hand, when the probability of a repetition itself is manipulated, predictable conditions can also increase estimated duration. This suggests that manipulations of expectations have different or even opposing effects on time perception. In previous studies, expectations were generated because stimuli were repeated or because the likelihood of a sequence or a repetition was varied. In the natural environment, however, expectations are often built via associative processes, for example, the context of a kitchen promotes the expectation of plates, appliances, and other associated objects. Here, we manipulated such association-based expectations by using oddballs that were either contextually associated or nonassociated with the standard items. We find that duration was more strongly overestimated for contextually associated oddballs. We reason that top-down attention is biased toward associated information, and thereby dilates subjective duration for associated oddballs. Based on this finding, we propose an interplay between top-down attention and predictive processing in the perception of time.

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.

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.

Influence of coexisting phases on the surface dilatational viscosity of Langmuir monolayers.

PubMed

Lopez, Juan M; Vogel, Michael J; Hirsa, Amir H

2004-11-01

Monolayer hydrodynamics are usually described in terms of a Newtonian constitutive relationship. However, this macroscopic view fails to account for small-scale coexisting phase domains, which are generally present in the monolayer and appear to have profound macroscopic effects. Here, we provide direct evidence of these effects, consisting of Brewster angle microscopy images of the monolayer, space- and time-resolved interfacial velocity measurements, and comparisons with predictions based on the Navier-Stokes equations together with the classic model for a Newtonian interface.

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.

A Comparison of Over-the-Counter Mechanical Nasal Dilators: A Systematic Review.

PubMed

Kiyohara, Nicole; Badger, Christopher; Tjoa, Tjoson; Wong, Brian

2016-09-01

The internal nasal valve is the narrowest part of the nasal airway and a common site of inspiratory collapse and obstruction of nasal airflow. Over-the-counter mechanical nasal dilators are an alternative to surgical intervention that attempts to improve airflow through the internal nasal valve. To determine the efficacy of over-the-counter mechanical nasal dilators and classify these products by mechanism. A database of 33 available over-the-counter mechanical nasal dilators was generated via a PubMed search as well as an internet search via Amazon.com and Google, conducted from April 1, 2013, through December 31, 2015. Products determined to be unavailable or discontinued were excluded from the database. Of the devices examined in published literature, efficacy was based on objective measures, such as measured airflow, the cross-sectional area of the nasal valve, and changes in resistance. Measures of reported sleep quality or patient perception were excluded. An analysis of each product's mechanism revealed 4 broad classes: external nasal dilator strips, nasal stents, nasal clips, and septal stimulators. A review demonstrated 5 studies supporting the use of external nasal dilator strips, 4 studies supporting the use of nasal clips, 1 study supporting the use of nasal stents, and no studies supporting the use of septal stimulators. Our findings suggest that external nasal dilator strips and nasal clips effectively relieve obstruction of the internal nasal valve and may be an alternative to surgical intervention in some patients.

Effects of soil aggregates on debris-flow mobilization: Results from ring-shear experiments

USGS Publications Warehouse

Iverson, Neal R.; Mann, Janet E.; Iverson, Richard M.

2010-01-01

Rates and styles of landslide motion are sensitive to pore-water pressure changes caused by changes in soil porosity accompanying shear deformation. Soil may either contract or dilate upon shearing, depending upon whether its initial porosity is greater or less, respectively, than a critical-state porosity attained after sufficiently high strain. We observed complications in this behavior, however, during rate-controlled (0.02 m s−1) ring-shear experiments conducted on naturally aggregated dense loamy sand at low confining stresses (10.6 and 40 kPa). The aggregated soil first dilated and then contracted to porosities less than initial values, whereas the same soil with its aggregates destroyed monotonically dilated. We infer that aggregates persisted initially during shear and caused dilation before their eventual breakdown enabled net contraction. An implication of this contraction, demonstrated in experiments in which initial soil porosity was varied, is that the value of porosity distinguishing initially contractive from dilative behavior can be significantly larger than the critical-state porosity, which develops only after disaggregation ceases at high strains. In addition, post-dilative contraction may produce excess pore pressures, thereby reducing frictional strength and facilitating debris-flow mobilization. We infer that results of triaxial tests, which generally produce strains at least a factor of ∼ 4 smaller than those we observed at the inception of post-dilative contraction, do not allow soil contraction to be ruled out as a mechanism for debris-flow mobilization in dense soils containing aggregates.

SGS Modeling of the Internal Energy Equation in LES of Supersonic Channel Flow

NASA Astrophysics Data System (ADS)

Raghunath, Sriram; Brereton, Giles

2011-11-01

DNS of fully-developed turbulent supersonic channel flows (Reτ = 190) at up to Mach 3 indicate that the turbulent heat fluxes depend only weakly on Mach number, while the viscous dissipation and pressure dilatation do so strongly. Moreover, pressure dilatation makes a significant contribution to the internal energy budget at Mach 3 and higher. The balance between these terms is critical to determining the temperature (and so molecular viscosity) from the internal energy equation and so, in LES of these flows, it is essential to use accurate SGS models for the viscous dissipation and the pressure dilatation. In this talk, we present LES results for supersonic channel flow, using SGS models for these terms that are based on the resolved-scale dilatation, an inverse timescale, and SGS momentum fluxes, which intrinsically represent this Mach number effect.

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

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.

Role of ion channels and subcellular Ca2+ signaling in arachidonic acid-induced dilation of pressurized retinal arterioles.

PubMed

Kur, Joanna; McGahon, Mary K; Fernández, Jose A; Scholfield, C Norman; McGeown, J Graham; Curtis, Tim M

2014-05-02

To investigate the mechanisms responsible for the dilatation of rat retinal arterioles in response to arachidonic acid (AA). Changes in the diameter of isolated, pressurized rat retinal arterioles were measured in the presence of AA alone and following pre-incubation with pharmacologic agents inhibiting Ca(2+) sparks and oscillations and K(+) channels. Subcellular Ca(2+) signals were recorded in arteriolar myocytes using Fluo-4-based confocal imaging. The effects of AA on membrane currents of retinal arteriolar myocytes were studied using whole-cell perforated patch clamp recording. Arachidonic acid dilated pressurized retinal arterioles under conditions of myogenic tone. Eicosatetraynoic acid (ETYA) exerted a similar effect, but unlike AA, its effects were rapidly reversible. Arachidonic acid-induced dilation was associated with an inhibition of subcellular Ca(2+) signals. Interventions known to block Ca(2+) sparks and oscillations in retinal arterioles caused dilatation and inhibited AA-induced vasodilator responses. Arachidonic acid accelerated the rate of inactivation of the A-type Kv current and the voltage dependence of inactivation was shifted to more negative membrane potentials. It also enhanced voltage-activated and spontaneous large-conductance calcium-activated K(+) (BK) currents, but only at positive membrane potentials. Pharmacologic inhibition of A-type Kv and BK currents failed to block AA-induced vasodilator responses. Arachidonic acid suppressed L-type Ca(2+) currents. These results suggest that AA induces retinal arteriolar vasodilation by inhibiting subcellular Ca(2+)-signaling activity in retinal arteriolar myocytes, most likely through a mechanism involving the inhibition of L-type Ca(2+)-channel activity. Arachidonic acid actions on K(+) currents are inconsistent with a model in which K(+) channels contribute to the vasodilator effects of AA.

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.

Treatment of severe peptic esophageal stricture with Roux-en-Y partial gastrectomy, vagotomy, and endoscopic dilation. A follow-up study.

PubMed

Salo, J A; Ala-Kulju, K V; Heikkinen, L O; Kivilaakso, E O

1991-04-01

Eleven patients with dysphagia caused by severe esophageal stricture (length 2 to 10 cm) resulting from reflux esophagitis were treated with fibroendoscopic dilation (Eder-Puestow) and Roux-en-Y partial gastrectomy with vagotomy during 10 years (1979 to 1988). There was no operative mortality, but complications developed in three patients: One patient had a mediastinal abscess demanding thoracotomy as a result of esophageal perforation after dilatation; one had postoperative pneumonia; and one patient had ileus. After a mean follow-up of 4 years (range 1 to 10 years) esophagitis healed in all cases, as judged by endoscopy. Eight patients were asymptomatic, but three had slight transient dysphagia. Postoperatively one to eight dilations (average three to four) were needed to relieve dysphagia in the first postoperative year, but later the stricture healed in every case. Postoperative pH measurement was performed in six latest patients and showed complete absence of reflux in all cases. It is concluded that Roux-en-Y partial gastrectomy with vagotomy and endoscopic dilation is an effective, simple, and safe procedure in the management of severe peptic esophageal (acid or alkaline esophagitis) stricture. However, occasional postoperative dilations at the outpatient clinic are often needed in severe cases in the first postoperative year.

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

Bile Flow Phantom Model and Animal Bile Duct Dilation Model for Evaluating Biliary Plastic Stents with Advanced Hydrophilic Coating

PubMed Central

Kwon, Chang-Il; Kim, Gwangil; Jeong, Seok; Lee, Won Seop; Lee, Don Haeng; Ko, Kwang Hyun; Hong, Sung Pyo; Hahm, Ki Baik

2016-01-01

Background/Aims The efforts to improve biliary plastic stents (PSs) for decreasing biofilm formation and overcome short patency time have been continued. The aim of this study is to evaluate the effect of advanced hydrophilic coating for patency and biodurability of PS. Methods Using an in vitro bile flow phantom model, we compared patency between prototype PS with hydrophilic coating (PS+HC) and prototype PS without hydrophilic coating (PS−HC). We performed an analysis of the degree of luminal narrowing by microscopic examination. Using an in vivo swine bile duct dilation model made by endoscopic papillary closure and stent insertion, we evaluated biodurability of hydrophilic coating. Results In the phantom model, PS+HC showed less biofilm formation and luminal narrowing than PS−HC at 8 weeks (p<0.05). A total of 31 stents were inserted into the dilated bile duct of seven swine models, and 24 stents were successfully retrieved 8 weeks later. There was no statistical difference of stent patency between the polyethylene PS+HC and the polyurethane PS+HC. The biodurability of hydrophilic coating was sustained up to 8 weeks, when assessing the coating layer by scanning electron microscopy examination. Conclusions Advanced hydrophilic coating technology may extend the patency of PS compared to uncoated PS. PMID:27021507

The energy-release rate and “self-force” of dynamically expanding spherical and plane inclusion boundaries with dilatational eigenstrain

NASA Astrophysics Data System (ADS)

Markenscoff, Xanthippi; Ni, Luqun

2010-01-01

In the context of the linear theory of elasticity with eigenstrains, the radiated field including inertia effects of a spherical inclusion with dilatational eigenstrain radially expanding is obtained on the basis of the dynamic Green's function, and one of the half-space inclusion boundary (with dilatational eigenstrain) moving from rest in general subsonic motion is obtained by a limiting process from the spherically expanding inclusion as the radius tends to infinity while the eigenstrain remains constrained, and this is the minimum energy solution. The global energy-release rate required to move the plane inclusion boundary and to create an incremental region of eigenstrain is defined analogously to the one for moving cracks and dislocations and represents the mechanical rate of work needed to be provide for the expansion of the inclusion. The calculated value, which is the "self-force" of the expanding inclusion, has a static component plus a dynamic one depending only on the current value of the velocity, while in the case of the spherical boundary, there is an additional contribution accounting for the jump in the strain at the farthest part at the back of the inclusion having the time to reach the front boundary, thus making the dynamic "self-force" history dependent.

Clinical utility of progesterone receptor modulators and their effect on the endometrium.

PubMed

Spitz, Irving M

2009-08-01

In view of the spate of recent publications related to mifepristone and some second generation progesterone receptor modulators (PRMs), this appears to be an opportune time to view the clinical status of these compounds. Randomized double-blind placebo-controlled trials have been conducted with mifepristone, CDB-4124 (Proellex), CDB-2914 (VA 2914, Ulipristal) and asoprisnil (J867). All these PRMs are effective in the treatment of uterine fibroids where they are associated with a reduction in pain, bleeding and improvement in quality of life and decrease in fibroid size. CDB-4124 is also efficacious in endometriosis. Long-term treatment with PRMs may be associated with endometrial thickening on ultrasound and there have been reports of endometrial hyperplasia. Several reassuring recent publications have done much to explain the mechanism underlying these endometrial changes. The most common histological finding is cystic glandular dilatation often associated with both admixed estrogen (mitotic) and progestin (secretory) epithelial effects. This histology has not been previously encountered in clinical practice and should not be confused with endometrial hyperplasia. The endometrial thickness is related to this cystic glandular dilatation. At this stage of development, PRMs cannot be administered for longer than 3 or 4 months. Even over this time, there is improvement of symptoms associated with fibroids and endometriosis. Clinicians and pathologists need to be aware that the endometrial thickening and histological appearance do not represent endometrial hyperplasia.

Nitrosative stress uncovers potent β2-adrenergic receptor-linked vasodilation further enhanced by blockade of clathrin endosome formation.

PubMed

Frame, Mary D; Dewar, Anthony M; Calizo, Rhodora C; Qifti, Androniqi; Scarlata, Suzanne F

2018-06-01

This study investigated the effect of sodium nitroprusside (SNP) preexposure on vasodilation via the β-adrenergic receptor (BAR) system. SNP was used as a nitrosative/oxidative proinflammatory insult. Small arterioles were visualized by intravital microscopy in the hamster cheek pouch tissue (isoflurane, n = 45). Control dilation to isoproterenol (EC 50 : 10 -7 mol/l) became biphasic as a function of concentration after 2 min of exposure to SNP (10 -4 M), with increased potency at picomolar dilation uncovered and decreased efficacy at the micromolar dilation. Control dilation to curcumin was likewise altered after SNP, but only the increased potency at a low dose was uncovered, whereas micromolar dilation was eliminated. The picomolar dilations were blocked by the potent BAR-2 inverse agonist carazolol (10 -9 mol/l). Dynamin inhibition with dynasore mimicked this effect, suggesting that SNP preexposure prevented BAR agonist internalization. Using HeLa cells transfected with BAR-2 tagged with monomeric red fluorescent protein, exposure to 10 -8 -10 -6 mol/l curcumin resulted in internalization and colocalization of BAR-2 and curcumin (FRET) that was prevented by oxidative stress (10 -3 mol/l CoCl 2 ), supporting that stress prevented internalization of the BAR agonist with the micromolar agonist. This study presents novel data supporting that distinct pools of BARs are differentially available after inflammatory insult. NEW & NOTEWORTHY Preexposure to an oxidative/nitrosative proinflammatory insult provides a "protective preconditioning" against future oxidative damage. We examined immediate vasoactive and molecular consequences of a brief preexposure via β-adrenergic receptor signaling in small arterioles. Blocked receptor internalization with elevated reactive oxygen levels coincides with a significant and unexpected vasodilation to β-adrenergic agonists at picomolar doses.

Resveratrol Inhibits Aortic Root Dilatation in the Fbn1C1039G/+ Marfan Mouse Model.

PubMed

Hibender, Stijntje; Franken, Romy; van Roomen, Cindy; Ter Braake, Anique; van der Made, Ingeborg; Schermer, Edith E; Gunst, Quinn; van den Hoff, Maurice J; Lutgens, Esther; Pinto, Yigal M; Groenink, Maarten; Zwinderman, Aeilko H; Mulder, Barbara J M; de Vries, Carlie J M; de Waard, Vivian

2016-08-01

Marfan syndrome (MFS) is a connective tissue disorder caused by mutations in the fibrillin-1 gene. Patients with MFS are at risk of aortic aneurysm formation and dissection. Usually, blood pressure-lowering drugs are used to reduce aortic events; however, this is not sufficient for most patients. In the aorta of smooth muscle cell-specific sirtuin-1-deficient mice, spontaneous aneurysm formation and senescence are observed. Resveratrol is known to enhance sirtuin-1 activity and to reduce senescence, which prompted us to investigate the effectiveness of resveratrol in inhibition of aortic dilatation in the Fbn1(C1039G/+) MFS mouse model. Aortic senescence strongly correlates with aortic root dilatation rate in MFS mice. However, although resveratrol inhibits aortic dilatation, it only shows a trend toward reduced aortic senescence. Resveratrol enhances nuclear localization of sirtuin-1 in the vessel wall and, in contrast to losartan, does not affect leukocyte infiltration nor activation of SMAD2 and extracellular signal-regulated kinases 1/2 (ERK1/2). Interestingly, specific sirtuin-1 activation (SRT1720) or inhibition (sirtinol) in MFS mice does not affect aortic root dilatation rate, although senescence is changed. Resveratrol reduces aortic elastin breaks and decreases micro-RNA-29b expression coinciding with enhanced antiapoptotic Bcl-2 expression and decreased number of terminal apoptotic cells. In cultured smooth muscle cells, the resveratrol effect on micro-RNA-29b downregulation is endothelial cell and nuclear factor κB-dependent. Resveratrol inhibits aortic root dilatation in MFS mice by promoting elastin integrity and smooth muscle cell survival, involving downregulation of the aneurysm-related micro-RNA-29b in the aorta. On the basis of these data, resveratrol holds promise as a novel intervention strategy for patients with MFS. © 2016 The Authors.

Resveratrol Inhibits Aortic Root Dilatation in the Fbn1C1039G/+ Marfan Mouse Model

PubMed Central

Hibender, Stijntje; Franken, Romy; van Roomen, Cindy; ter Braake, Anique; van der Made, Ingeborg; Schermer, Edith E.; Gunst, Quinn; van den Hoff, Maurice J.; Lutgens, Esther; Pinto, Yigal M.; Groenink, Maarten; Zwinderman, Aeilko H.; Mulder, Barbara J.M.; de Vries, Carlie J.M.

2016-01-01

Objective— Marfan syndrome (MFS) is a connective tissue disorder caused by mutations in the fibrillin-1 gene. Patients with MFS are at risk of aortic aneurysm formation and dissection. Usually, blood pressure–lowering drugs are used to reduce aortic events; however, this is not sufficient for most patients. In the aorta of smooth muscle cell–specific sirtuin-1–deficient mice, spontaneous aneurysm formation and senescence are observed. Resveratrol is known to enhance sirtuin-1 activity and to reduce senescence, which prompted us to investigate the effectiveness of resveratrol in inhibition of aortic dilatation in the Fbn1C1039G/+ MFS mouse model. Approach and Results— Aortic senescence strongly correlates with aortic root dilatation rate in MFS mice. However, although resveratrol inhibits aortic dilatation, it only shows a trend toward reduced aortic senescence. Resveratrol enhances nuclear localization of sirtuin-1 in the vessel wall and, in contrast to losartan, does not affect leukocyte infiltration nor activation of SMAD2 and extracellular signal–regulated kinases 1/2 (ERK1/2). Interestingly, specific sirtuin-1 activation (SRT1720) or inhibition (sirtinol) in MFS mice does not affect aortic root dilatation rate, although senescence is changed. Resveratrol reduces aortic elastin breaks and decreases micro-RNA-29b expression coinciding with enhanced antiapoptotic Bcl-2 expression and decreased number of terminal apoptotic cells. In cultured smooth muscle cells, the resveratrol effect on micro-RNA-29b downregulation is endothelial cell and nuclear factor κB-dependent. Conclusions— Resveratrol inhibits aortic root dilatation in MFS mice by promoting elastin integrity and smooth muscle cell survival, involving downregulation of the aneurysm-related micro-RNA-29b in the aorta. On the basis of these data, resveratrol holds promise as a novel intervention strategy for patients with MFS. PMID:27283746

[A clinical observation of percutaneous balloon dilation and maintenance percutaneous transhepatic cholangial catheter drainage for treatment of 21 patients with benign biliary strictures and difficult endoscopy].

PubMed

Pan, Jie; Shi, Hai-feng; Li, Xiao-guang; Zhang, Xiao-bo; Liu, Wei; Jin, Zheng-yu; Hong, Tao; Yang, Ai-ming; Yang, Ning

2012-06-01

To investigate the value of percutaneous balloon dilation and percutaneous transhepatic cholangial drainage (PTCD) catheter maintenance in the treatment of benign biliary strictures. The clinical data of 21 patients with benign biliary strictures at Peking Union Medical College Hospital from June 2005 to June 2011 were retrospectively studied, in which 12 patients in severe stricture (stenosis > 70%) were treated with percutaneous balloon dilation and PTCD catheter placed across the stricture, while another 9 patients in median stricture (stenosis < 70%) were only treated with PTCD catheter maintenance. Of the 12 patients underwent balloon dilation and 6 - 12 months (median: 9 months) of PTCD catheter placement, 11 patients had the catheter successfully removed. In the follow-up of 6 - 24 months (median: 10 months), patency of bile duct was preserved in 9 of 11 patients, and recurrent stenosis was seen in 2 patients. A severe complication with biliary artery branch rupture and massive hemobilia was seen in 1 patient during balloon dilation. Of the 9 patients only treated with 1 - 12 months (median: 6 months) of PTCD catheter placement, 7 patients had the catheter successfully removed. In the follow-up of 5 - 18 months (median: 8 months), patency of bile duct was preserved in 5 of 7 patients, and recurrent stenosis was seen in 2 patients. No severe complication occurred. When endoscopy therapy is failed or the patient can't undergo endoscopy therapy, the percutaneous balloon dilation and PTCD catheter maintenance method is an effective alternative therapeutic approach in the treatment of benign biliary strictures. The moderate benign biliary stricture may be effectively treated only by the PTCD catheter maintenance method.

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.

Two-Phase Solid/Fluid Simulation of Dense Granular Flows With Dilatancy Effects

NASA Astrophysics Data System (ADS)

Mangeney, A.; Bouchut, F.; Fernández-Nieto, E. D.; Kone, E. H.; Narbona-Reina, G.

2016-12-01

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. By comparing quantitatively 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).

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 Central

Bhattar, Rohit; Jain, Vipin; Tomar, Vinay; Yadav, Sher Singh

2017-01-01

Objective 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. Material and methods 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. Results 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). Conclusion 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. PMID:29201512

Comparing the efficacy of mydriatic cocktail-soaked sponge and conventional pupil dilation in patients using tamsulosin – a randomized controlled trial

PubMed Central

2013-01-01

Background A strong association exists between the use of tamsulosin and the occurance of intraoperative floppy iris syndrome. Several methods were advocated to overcome the progressive intraopertive miosis. Our purpose was to investigate the effect of a mydriatic-cocktail soaked cellulose sponge on perioperative pupil diameter in tamsulosin-treated patients undergoing elective cataract surgery. Methods Patients using tamsulosin were dilated either with mydriatic-cocktail soaked sponge (group 1) or with conventional eyedrop regimen (group 2). Control patients not taking any α1 adrenergic receptor inhibtors were also dilated with mydriatic sponge (group 3). In all groups oxybuprocain 0.4%, cocain 4%, tropicamide 1%, phenylephrine 10%, diclophenac 0.1% along with chloramphenicol 0.5% were used preoperatively. Pupil diameter (mm) was measured preoperatively, after nucleus delivery, and before IOL implantation. Adverse effects associated with the use of sponge, minor and major intraoperative complications, the use of iris retractors and operation time were recorded. Differences in general between groups were analyzed with a one way analysis of variance (ANOVA); differences between groups in proportions were assessed by Fisher’s exact test. Results Mean pupil diameter (mm) was preopertively: 7.52 ± 1.21, 7.30 ± 1.55 and 7.99 ± 0.96 (ANOVA: p = 0.079); after nucleus delivery: 6 ± 1.20, 6.29 ± 1.12 and 6.52 ± 0.81 (ANOVA: p = 0.123); before IOL implantation: 5.46 ± 1.06, 5.83 ± 1.09 and 6.17 ± 0.89 (ANOVA: p = 0.0291). No adverse effect related to sponge use was detected. Frequency of minor complications, and iris hook use was similar in the two tamsulosin treated group. Operation time did not differ significantly in the three groups. Conclusion We have found that using a mydriatic cocktail-soaked wick – an alternative way to achieve intraoperative mydriasis for cataract surgery – was as effective and safe as the conventional repeated eyedrops regiment for tamsulosin treated patients. Trial registration Current Controlled Trials ISRCTN37834752 PMID:24359572

[The possibility of antepartal prevention of episiotomy and perineal tears during delivery].

PubMed

Bohatá, P; Dostálek, L

To determine the effect of antepartal methods on the prevention of birth injuries in primiparous women. Retrospective study. Nemocnice Český Krumlov, a.s. Between February 2014 and November 2015 were 315 primiparous women questioned after a vaginal delivery on the use of methods of birth injury prevention (vaginal dilatators EPI-NO and Aniball, perineal massage, natural methods - raspberry-leaf tea or linseed). Consecutively, the rates of intact perineum, perineal tears and episiotomies among respective methods were compared with the control group using no preventive method. The effects of the methods were tested on the occurrence of spontaneous or vaginal operative delivery. There was a significantly higher number of women with intact perineum after the use of vaginal dilatators (43.1% vs.14.1% in control group (p < 0.001). We also found a significant reduction of episiotomies in this group (29.3% vs. 57.7%, p < 0.001). There was no significant effect of perineal massage, raspberry-leaf tea or linseed on perineum injury prevention. A lower occurrence of vaginal operative delivery was also confirmed in the group of women using vaginal dilatators (p = 0.02). Significant benefit of the use of the antepartal vaginal dilatators in the reduction of birth injuries was shown as well as of the occurrence of vaginal operative delivery.

The effect of losartan on progressive aortic dilatation in patients with Marfan's syndrome: a meta-analysis of prospective randomized clinical trials.

PubMed

Gao, Linggen; Chen, Lei; Fan, Li; Gao, Dewei; Liang, Zhiru; Wang, Rong; Lu, Wenning

2016-08-15

To assess the effect of losartan therapy on progressive aortic dilatation and on clinical outcome in patients with Marfan's syndrome (MFS). The meta-analysis was instituted, which included studies identified by a systematic review of MEDLINE of peer-reviewed publications. Echocardiogram or MRI measurements of the aortic root dimension and outcome measures of death, cardiovascular surgery and aortic dissection or rupture were compared between patients who were treated and untreated with losartan therapy. Six randomized trials with 1398 subjects met all the inclusion criteria and were included in the meta-analysis. Compared with non-losartan treatment, losartan therapy significantly decreased the rate of aortic dilatation (SMD=-0.13 with 95% CI -0.25 to 0.00, p=0.04). The clinical outcome beneficial was not observed in the losartan treatment group when compared with no losartan treatment group (odds ratio=1.04 with 95% CI of 0.57-1.87). Given the current results of the meta-analysis and together with the lack of associated side effects, it would be reasonable to use losartan in MFS patients with aortic root dilatation. However, no clinical outcome benefits were observed in the losartan treatment group when compared with no losartan treatment group. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Modified tube gastropexy using a mushroom-tipped silicone catheter for management of gastric dilatation-volvulus in dogs.

PubMed

Belch, A; Rubinos, C; Barnes, D C; Nelissen, P

2017-02-01

To report the short- and long-term complications and clinical outcomes of a cohort of dogs managed for gastric dilatation-volvulus using a modified right-sided tube gastropexy technique. Retrospective case series. Of 31 dogs treated, 29 (93·5%) had an excellent short-term outcome, and gastric dilatation-volvulus did not recur in any dog. Twenty-six dogs (84%) were initially fed via the gastrostomy tube postoperatively; three (9·7%) suffered a major complication including septic peritonitis (n=1), and premature tube removal (n=2). Fourteen dogs (45·1%) had minor complications including mild, self-limiting discharge from the stoma site in 13. Modified tube gastropexy using a mushroom-tipped silicone catheter is an effective and safe surgical method for the management of gastric dilatation-volvulus. The gastrostomy tube allowed early enteral feeding and easy administration of medications, including gastroprotectants. © 2017 British Small Animal Veterinary Association.

Multi-Detector Row Computed Tomography Findings of Pelvic Congestion Syndrome Caused by Dilated Ovarian Veins

PubMed Central

Eren, Suat

2010-01-01

Objective: To evaluate the efficacy of multi-detector row CT (MDCT) on pelvic congestion syndrome (PCS), which is often overlooked or poorly visualized with routine imaging examination. Materials and Methods: We evaluated the MDCT features of 40 patients with PCS (mean age, 45 years; range, 29–60 years) using axial, coronal, sagittal, 3D volume-rendered, and Maximum Intensity Projection MIP images. Results: MDCT revealed pelvic varices and ovarian vein dilatations in all patients. Bilateral ovarian vein dilatation was present in 25 patients, and 15 patients had unilateral dilatation. While 12 cases of secondary pelvic varices occurred simultaneously with a retroaortic left renal vein, 10 cases were due solely to a mass obstruction or stenosis of venous structures. Conclusion: MDCT is an effective tool in the evaluation of PCS, and it has more advantages than other imaging modalities. PMID:25610142

Endoscopic Management of Benign Esophageal Strictures.

PubMed

Ravich, William J

2017-08-24

This paper presents the author's approach to esophageal dilation. It offers a tailored approach to the application of dilation to specific types of esophageal stenotic lesions. In patients with inflammatory stricture, recent studies confirm the importance of treating the underlying inflammatory condition in order to decrease the rate of recurrence. The paper reviews some of the novel techniques that have been suggested for the treatment of refractory benign esophageal strictures, including incisional therapy, stenting, or the injection steroids or antifibrotic agents. The endoscopist who treats esophageal strictures must be familiar with the tools of the dilation and how they are best applied to specific types of stenotic lesions. If inflammation is present, effective management requires treatment of the inflammatory process in addition to mechanical dilation of the stenotic lesion. Controlled trials of novel approaches to treatment of refractory benign esophageal strictures are limited and will be necessary to determine efficacy.

Pressure-strain energy redistribution in compressible turbulence: return-to-isotropy versus kinetic-potential energy equipartition

NASA Astrophysics Data System (ADS)

Lee, Kurnchul; Venugopal, Vishnu; Girimaji, Sharath S.

2016-08-01

Return-to-isotropy and kinetic-potential energy equipartition are two fundamental pressure-moderated energy redistributive processes in anisotropic compressible turbulence. Pressure-strain correlation tensor redistributes energy among various Reynolds stress components and pressure-dilatation is responsible for energy reallocation between dilatational kinetic and potential energies. The competition and interplay between these pressure-based processes are investigated in this study. Direct numerical simulations (DNS) of low turbulent Mach number dilatational turbulence are performed employing the hybrid thermal Lattice Boltzman method (HTLBM). It is found that a tendency towards equipartition precedes proclivity for isotropization. An evolution towards equipartition has a collateral but critical effect on return-to-isotropy. The preferential transfer of energy from strong (rather than weak) Reynolds stress components to potential energy accelerates the isotropization of dilatational fluctuations. Understanding of these pressure-based redistributive processes is critical for developing insight into the character of compressible turbulence.

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& ...

Does dilation and curettage versus expectant management for spontaneous abortion in patients undergoing in vitro fertilization affect subsequent endometrial development?

PubMed

Moon, Kimberly S; Richter, Kevin S; Levy, Michael J; Widra, Eric A

2009-11-01

In in vitro fertilization patients, treatment of spontaneous abortion with dilation and curettage (D&C) versus expectant management has no long-term effect on subsequent endometrial development, as measured by change in endometrial thickness. A transient reduction in endometrial thickness was found within the first 6 months after D&C, which is a novel finding, but it is likely to have little or no effect on pregnancy rates given the small absolute effect on endometrial thickness.

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.

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.

Endoscopic management of post-laparoscopic sleeve gastrectomy stenosis.

PubMed

Al Sabah, Salman; Al Haddad, Eliana; Siddique, Iqbal

2017-09-01

Laparoscopic sleeve gastrectomy (LSG) is becoming an increasingly popular form of bariatric surgery, accounting for more than 50% of these procedures performed in the USA. Given this popularity, more is being understood about the complications associated with LSG, which, though uncommon, include the formation of strictures and stenosis. The purpose of this study is to establish a safe and effective protocol for the treatment of stenosis post-LSG using endoscopic balloon dilatation. This is a prospective review of 26 patients who had undergone LSG in Kuwait, followed by sleeve gastrectomy stenosis (SGS) and were then referred to Amiri Hospital for endoscopic balloon dilatation from October 2008 up to June 2016. A total of 26 patients (four males; 22 females) presented with symptoms of stenosis post-LSG during the study period. The mean age of the patients was 34.6 ± 10.8 years. The mean body mass index at the time of surgery was 43 ± 1.6 kg/m 2 . The median interval from the initial LSG surgery was 95 days. Nine patients had an early presentation (≤3 months from surgery), while 17 presented late (>3 months). The patients were followed for a mean duration of 156 ± 20 days from the last endoscopic balloon dilatation. A total of 23 (88.5%) patients had complete resolution of their symptoms. Adverse events were observed in one patients, who was removed from the study. Gastric stenosis is a rare but potentially serious complication of LSG. Serial dilatation of SGS employing endoscopic balloons is a safe method of treatment, with high efficacy rates. This new method may offer a less invasive alternative to surgical revision. However, if endoscopic treatment fails, surgery is necessary.

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.

Dilation and breakage dissipation of granular soils subjected to monotonic loading

NASA Astrophysics Data System (ADS)

Sun, Yifei; Xiao, Yang; Ji, Hua

2016-12-01

Dilation and breakage energy dissipation of four different granular soils are investigated by using an energy balance equation. Due to particle breakage, the dilation curve does not necessarily pass through the origin of coordinates. Breakage energy dissipation is found to increase significantly at the initial loading stage and then gradually become stabilised. The incremental dissipation ratio between breakage energy and plastic work exhibits almost independence of the confining pressure. Accordingly, a plastic flow rule considering the effect of particle breakage is suggested. The critical state friction angle is found to be a combination of the basic friction between particles and the friction contributed by particle breakage.

Modeling of Inhomogeneous Compressible Turbulence Using a Two-Scale Statistical Theory

NASA Technical Reports Server (NTRS)

Hamba, Fujihiro

1996-01-01

Turbulence modeling plays an important role in the study of high-speed flows in engineering and aerodynamic problems; they include flows in supersonic combustion engines and over hypersonic transport aircraft. The enhancement of the kinetic energy dissipation by the dilatational terms is one of the typical compressibility effects. Zeman (1990) and Sarkar et al. (1991) proposed that the dilatation dissipation is proportional to the solenoidal dissipation and is a function of the turbulent Mach number. Sarkar (1992) also modeled the pressure-dilatation correlation using the turbulent Mach number. Zeman (1991) related the correlation to the rate of change of the pressure variance.

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.

Neostigmine but not sugammadex impairs upper airway dilator muscle activity and breathing

PubMed Central

Eikermann, M.; Zaremba, S.; Malhotra, A.; Jordan, A. S.; Rosow, C.; Chamberlin, N. L.

2008-01-01

Background Cholinesterase inhibitor-based reversal agents, given in the absence of neuromuscular block, evoke a partial upper airway obstruction by decreasing skeletal upper airway muscle function. Sugammadex reverses neuromuscular block by encapsulating rocuronium. However, its effects on upper airway integrity and breathing are unknown. Methods Fifty-one adult male rats were anaesthetized with isoflurane, tracheostomized, and a femoral artery and vein were cannulated. First, we compared the efficacy of sugammadex 15 mg kg−1 and neostigmine 0.06 mg kg−1 to reverse respiratory effects of rocuronium-induced partial paralysis [train-of-four ratio (T4/T1)=0.5]. Subsequently, we compared the safety of sugammadex and neostigmine given after recovery of the T4/T1 to 1, by measuring phasic genioglossus activity and breathing. Results During partial paralysis (T4/T1=0.5), time to recovery of minute volume to baseline values was 10.9 (2), 75.8 (18), and 153 (54) s with sugammadex, neostigmine, and placebo, respectively (sugammadex was significantly faster than neostigmine and placebo, P<0.05). Recovery of T4/T1 was also faster for sugammadex than neostigmine and placebo. Neostigmine administration after complete recovery of T4/T1 decreased upper airway dilator muscle activity to 64 (30)% of baseline and decreased tidal volume (P<0.05 for both variables), whereas sugammadex had no effect on either variable. Conclusions In contrast to neostigmine, which significantly impairs upper airway dilator muscle activity when given after recovery from neuromuscular block, a reversal dose of sugammadex given under the same conditions does not affect genioglossus muscle activity and normal breathing. Human studies will be required to evaluate the clinical relevance of our findings. PMID:18559352

Allogeneic Cardiospheres Delivered via Percutaneous Transendocardial Injection Increase Viable Myocardium, Decrease Scar Size, and Attenuate Cardiac Dilatation in Porcine Ischemic Cardiomyopathy

PubMed Central

Tseliou, Eleni; Cheng, Ke; Luthringer, Daniel J.; Ho, Chak-Sum; Takayama, Kentaro; Minamino, Naoto; Dawkins, James F.; Chowdhury, Supurna; Duong, Doan Trang; Seinfeld, Jeffrey; Middleton, Ryan C.; Dharmakumar, Rohan; Li, Debiao; Marbán, Linda; Makkar, Raj R.; Marbán, Eduardo

2014-01-01

Background Epicardial injection of heart-derived cell products is safe and effective post-myocardial infarction (MI), but clinically-translatable transendocardial injection has never been evaluated. We sought to assess the feasibility, safety and efficacy of percutaneous transendocardial injection of heart-derived cells in porcine chronic ischemic cardiomyopathy. Methods and Results We studied a total of 89 minipigs; 63 completed the specified protocols. After NOGA-guided transendocardial injection, we quantified engraftment of escalating doses of allogeneic cardiospheres or cardiosphere-derived cells in minipigs (n = 22) post-MI. Next, a dose-ranging, blinded, randomized, placebo-controlled (“dose optimization”) study of transendocardial injection of the better-engrafting product was performed in infarcted minipigs (n = 16). Finally, the superior product and dose (150 million cardiospheres) were tested in a blinded, randomized, placebo-controlled (“pivotal”) study (n = 22). Contrast-enhanced cardiac MRI revealed that all cardiosphere doses preserved systolic function and attenuated remodeling. The maximum feasible dose (150 million cells) was most effective in reducing scar size, increasing viable myocardium and improving ejection fraction. In the pivotal study, eight weeks post-injection, histopathology demonstrated no excess inflammation, and no myocyte hypertrophy, in treated minipigs versus controls. No alloreactive donor-specific antibodies developed over time. MRI showed reduced scar size, increased viable mass, and attenuation of cardiac dilatation with no effect on ejection fraction in the treated group compared to placebo. Conclusions Dose-optimized injection of allogeneic cardiospheres is safe, decreases scar size, increases viable myocardium, and attenuates cardiac dilatation in porcine chronic ischemic cardiomyopathy. The decreases in scar size, mirrored by increases in viable myocardium, are consistent with therapeutic regeneration. PMID:25460005

Simple urethral dilatation, endoscopic urethrotomy, and urethroplasty for urethral stricture disease in adult men.

PubMed

Wong, Susan S W; Aboumarzouk, Omar M; Narahari, Radhakrishna; O'Riordan, Anna; Pickard, Robert

2012-12-12

Strictures of the urethra are the most common cause of obstructed micturition in younger men and frequently recur after initial treatment. Standard treatment comprises internal widening of the strictured area by simple dilatation or by telescope-guided internal cutting (optical urethrotomy), but these interventions are associated with a high failure rate requiring repeated treatment. The alternative option of open urethroplasty whereby the urethral lumen is permanently widened by removal or grafting of the strictured segment is less likely to fail but requires greater expertise. Findings of Improved choice of graft material and shortened hospital stay suggest that urethroplasty may be under utilised. The extent and quality of evidence guiding treatment choice for this condition are uncertain.   To determine which is the best surgical treatment for male urethral stricture disease taking into account relative efficacy, adverse event rates and cost-effectiveness.   We searched the Cochrane Incontinence Group Specialised Register (searched 21 June 2012), CENTRAL (2012, Issue 6), MEDLINE (January 1946 to week 2 June 2012), EMBASE (January 1980 to week 25 2012), OpenSIGLE (searched 26 June 2012), clinical trials registries and reference lists of relevant articles. We included publications reporting data from randomised or quasi-randomised controlled trials comparing the effectiveness of dilatation, urethrotomy and urethroplasty in the treatment of adult men with urethral stricture disease. Two authors evaluated trials for appropriateness for inclusion and methodological quality. Data extraction was performed using predetermined criteria. Analyses were carried out using the Cochrane Review Manager software (RevMan 5). Two randomised trials were identified. One trial compared the outcomes of surgical urethral dilatation and optical urethrotomy in 210 adult men with urethral stricture disease. No significant difference was found in the proportion of men being stricture free at three years or in the median time to recurrence. The second trial compared the outcomes of urethrotomy and urethroplasty in 50 men with traumatic stricture of the posterior urethra following pelvic fracture injury. In the first six months, men were more likely to require further surgery in the urethrotomy group than in the primary urethroplasty group (RR 3.39, 95% CI 1.62 to 7.07). After two years, 16 of 25 (64%) men initially treated by urethrotomy required continued self-dilatation or further surgery for stricture recurrence compared to 6 of 25 (24%) men treated by primary urethroplasty. There were insufficient data to perform meta-analysis or to reliably determine effect size. There were insufficient data to determine which intervention is best for urethral stricture disease in terms of balancing efficacy, adverse effects and costs. Well designed, adequately powered multi-centre trials are needed to answer relevant clinical questions regarding treatment of men with urethral strictures.

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.

Sex-specific effects of cardiovascular risk factors on endothelium-dependent dilation and endothelin activity in middle-aged women and men.

PubMed

Brar, Vijaywant; Gill, Sartaj; Cardillo, Carmine; Tesauro, Manfredi; Panza, Julio A; Campia, Umberto

2015-01-01

Healthy middle-aged postmenopausal women have higher endothelium-dependent dilation and lower vasoconstrictor activity of endothelin-1 than men. Whether these sex-specific differences extend to patients with cardiovascular risk factors has not been investigated. The current study aimed to determine whether, in patients with cardiovascular risk factors, sex-specific differences exist in endothelium-dependent dilation and endothelin-1 activity. Forearm blood flow responses were measured by strain-gauge plethysmography during the intra-arterial infusion of acetylcholine, sodium nitroprusside, and the selective endothelin type A receptor blocker BQ-123 in 50 women and 64 men with cardiovascular risk factors. Acetylcholine and sodium nitroprusside induced a significant vasodilation in women and men alike (p < 0.01 for both). Also BQ-123 caused a significant vasodilation (p < 0.001) in both groups. The vasodilator response to acetylcholine was greater in women compared to men; however there were no differences in the response to sodium nitroprusside and BQ-123 (p = NS for both) between the two sex groups. Middle-aged women with cardiovascular risk factors have significantly higher endothelium-dependent dilation than middle-aged men; however, vascular endothelin 1 activity is similar in the two groups. These findings suggest that the presence of cardiovascular risk factors is associated with sex-specific effects on endothelium-dependent dilation but not on endothelin 1 activity. Further study is needed to confirm our findings and to characterize the mechanisms underlying this sex-specific regulation of endothelial function.

Alterations in atrial electrophysiology and tissue structure in a canine model of chronic atrial dilatation due to mitral regurgitation.

PubMed

Verheule, Sander; Wilson, Emily; Everett, Thomas; Shanbhag, Sujata; Golden, Catherine; Olgin, Jeffrey

2003-05-27

Clinically, chronic atrial dilatation is associated with an increased incidence of atrial fibrillation (AF), but the underlying mechanism is not clear. We have investigated atrial electrophysiology and tissue structure in a canine model of chronic atrial dilatation due to mitral regurgitation (MR). Thirteen control and 19 MR dogs (1 month after partial mitral valve avulsion) were studied. Dogs in the MR group were monitored using echocardiography and Holter recording. In open-chest follow-up experiments, electrode arrays were placed on the atria to investigate conduction patterns, effective refractory periods, and inducibility of AF. Alterations in tissue structure and ultrastructure were assessed in atrial tissue samples. At follow-up, left atrial length in MR dogs was 4.09+/-0.45 cm, compared with 3.25+/-0.28 at baseline (P<0.01), corresponding to a volume of 205+/-61% of baseline. At follow-up, no differences in atrial conduction pattern and conduction velocities were noted between control and MR dogs. Effective refractory periods were increased homogeneously throughout the left and right atrium. Sustained AF (>1 hour) was inducible in 10 of 19 MR dogs and none of 13 control dogs (P<0.01). In the dilated MR left atrium, areas of increased interstitial fibrosis and chronic inflammation were accompanied by increased glycogen ultrastructurally. Chronic atrial dilatation in the absence of overt heart failure leads to an increased vulnerability to AF that is not based on a decrease in wavelength.

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

Local Limit Phenomena, Flow Compression, and Fuel Cracking Effects in High-Speed Turbulent Flames

DTIC Science & Technology

2015-06-01

e.g. local extinction and re- ignition , interactions between flow compression and fast-reaction induced dilatation (reaction compression ), and to...time as a function of initial temperature in constant-pressure auto - ignition , and (b) the S-curves of perfectly stirred reactors (PSRs), for n...mechanism. The reduction covered auto - ignition and perfectly stirred reactors for equivalence ratio range of 0.5~1.5, initial temperature higher than

Dilatation-dissipation corrections for advanced turbulence models

NASA Technical Reports Server (NTRS)

Wilcox, David C.

1992-01-01

This paper analyzes dilatation-dissipation based compressibility corrections for advanced turbulence models. Numerical computations verify that the dilatation-dissipation corrections devised by Sarkar and Zeman greatly improve both the k-omega and k-epsilon model predicted effect of Mach number on spreading rate. However, computations with the k-gamma model also show that the Sarkar/Zeman terms cause an undesired reduction in skin friction for the compressible flat-plate boundary layer. A perturbation solution for the compressible wall layer shows that the Sarkar and Zeman terms reduce the effective von Karman constant in the law of the wall. This is the source of the inaccurate k-gamma model skin-friction predictions for the flat-plate boundary layer. The perturbation solution also shows that the k-epsilon model has an inherent flaw for compressible boundary layers that is not compensated for by the dilatation-dissipation corrections. A compressibility modification for k-gamma and k-epsilon models is proposed that is similar to those of Sarkar and Zeman. The new compressibility term permits accurate predictions for the compressible mixing layer, flat-plate boundary layer, and a shock separated flow with the same values for all closure coefficients.

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.

Beta-2- Adrenergic Receptor Genotype and Other Variables that Contribute to Labor Pain and Progress

PubMed Central

Reitman, Elena; Conell-Price, Jessamyn; Evansmilth, Jennifer; Olson, Luke; Drosinos, Sofia; Jasper, Nancy; Randolph, Paula; Smiley, Richard; Shafer, Steven; Flood, Pamela

2011-01-01

Background Beta-2-adrenergic receptor (β2AR) activity influences labor and its genotype affects the incidence of preterm delivery. We determined the effect of β2AR genotype on term labor progress and pain. Methods We prospectively enrolled 150 nulliparous parturients in the third trimester and obtained sensory thresholds, demographic information and DNA. Cervical dilation, pain scores and labor management data were extracted with associated times. The association of genetic and demographic factors with labor was tested with mixed effects models. Results Parturients who express Gln at the 27 position of the β2AR had slower labor (P<0.03). They progressedfrom 1–10cm dilation in approximately 21 hours compared to 14 hours in otherpatients. Asian ethnicity, previously associated with slower labor, is highly associated with this polymorphism (P<0.0001). Heavier and Black patients had slower latent labor (P<0.01, 0.01) and neuraxial analgesia was associated with slower labor progress (P<0.0001). It could take up to 36 hours for the heaviest and the Black parturients to transition from 1cm cervical dilation to active labor; however once the active phase began, labor rate was the same as other patients’. Conclusion We detected a strong association between β2AR genotype and slower labor. Asian ethnicity may be a proxy for β2AR genotype. Black and heavy women have slower latent labor. These results confirm many of the associations found when this mathematical model was applied to a large retrospectivecohort, further validating this approach to description and analysis of labor progress. PMID:21394004

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.

High-precision piezo-ejection ocular microdosing: Phase II study on local and systemic effects of topical phenylephrine.

PubMed

Ianchulev, Tsontcho; Weinreb, Robert; Tsai, James C; Lin, Shan; Pasquale, Louis R

2018-01-01

Conventional eyedropper-delivered volumes (25-50 µl) exceed the eye's usual tear-film volume (7 µl) and precorneal reservoir capacity, risking overflow and ocular/systemic complications. Piezoelectric high-precision microdosing may circumvent these limitations. Results & methodology: In this masked, nonrandomized, cross-over study, subjects (n = 12) underwent pupil dilation with topical phenylephrine (PE) administered by 32-µl eyedropper (2.5% or 10% formulation) and 8-µl electronic microdosing (10% formulation). Microdosing with PE-10% achieved comparable peak dilation as 10% eyedropper-delivery and superior dilation to 2.5% eyedropper-delivery (p = 0.009) at 75 min. Microdosing significantly reduced 20-min plasma PE levels versus PE10% eyedropper; neither treatment altered heart rate/blood pressure. Eye irritation occurred significantly less frequently with microdosing than PE10% eyedrops. Piezo-ejection PE microdosing achieves comparable biological effect as eyedropper dosing; reduced systemic absorption may decrease risk of systemic side effects.

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.

Contribution of KV1.5 Channel to H2O2-Induced Human Arteriolar Dilation and its Modulation by Coronary Artery Disease

PubMed Central

Nishijima, Yoshinori; Cao, Sheng; Chabowski, Dawid S.; Korishettar, Ankush; Ge, Alyce; Zheng, Xiaodong; Sparapani, Rodney; Gutterman, David D.; Zhang, David X.

2016-01-01

Rationale Hydrogen peroxide (H2O2) regulates vascular tone in the human microcirculation under physiological and pathophysiological conditions. It dilates arterioles by activating BKCa channels in subjects with coronary artery disease (CAD), but its mechanisms of action in subjects without CAD (non-CAD) as compared to those with CAD remain unknown. Objective We hypothesize that H2O2-elicited dilation involves different K+ channels in non-CAD versus CAD, resulting in an altered capacity for vasodilation during disease. Methods and Results H2O2 induced endothelium-independent vasodilation in non-CAD adipose arterioles, which was reduced by paxilline, a BKCa channel blocker, and by 4-AP, a KV channel blocker. Assays of mRNA transcripts, protein expression and subcellular localization revealed that KV1.5 is the major KV1 channel expressed in vascular smooth muscle cells (VSMCs) and is abundantly localized on the plasma membrane. The selective KV1.5 blocker DPO-1 and the KV1.3/1.5 blocker Psora-4 reduced H2O2-elicited dilation to a similar extent as 4-AP, but the selective KV1.3 blocker PAP-1 was without effect. In arterioles from CAD subjects, H2O2-induced dilation was significantly reduced and this dilation was inhibited by paxilline but not by 4-AP, DPO-1 or Psora-4. KV1.5 cell membrane localization and DPO-1-sensitive K+ currents were markedly reduced in isolated VSMCs from CAD arterioles, although mRNA or total cellular protein expression were largely unchanged. Conclusions In human arterioles, H2O2-induced dilation is impaired in CAD, which is associated with a transition from a combined BKCa- and KV (KV1.5)-mediated vasodilation toward a BKCa-predominant mechanism of dilation. Loss of KV1.5 vasomotor function may play an important role in microvascular dysfunction in CAD or other vascular diseases. PMID:27872049

[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.

Effectiveness and safety of endoscopic radial incision and cutting for severe benign anastomotic stenosis after surgery for colorectal carcinoma: a three-case series.

PubMed

Asayama, Naoki; Nagata, Shinji; Shigita, Kenjiro; Aoyama, Taiki; Fukumoto, Akira; Mukai, Shinichi

2018-03-01

Benign colonic anastomotic stenosis sometimes occurs after surgical resection and usually requires surgical or endoscopic dilation. Limited data are available on the effectiveness and safety of the endoscopic radial incision and cutting (RIC) method at sites other than the esophagus. The aim of this retrospective study was to investigate the effectiveness and safety of RIC dilation for severe benign anastomotic colonic stenosis. Subjects were 3 men (median age 72 years, range 65 - 76 years) who developed severe benign anastomotic stenosis after surgical resection for colorectal carcinoma and were subsequently treated by RIC dilation at Hiroshima City Asa Citizens Hospital between May 2014 and December 2016. Severe anastomotic stenosis was defined as a narrowed anastomosis through which a standard colonoscope could not be passed. The median interval from surgery to RIC was 21 months (range 9 - 29 months). RIC was successful in all 3 patients and reduced the severity of dyschezia postoperatively; 2 patients experienced improvement after a single RIC session and the other after 6 RIC sessions. No treatment-related adverse events or re-stenosis requiring repeat dilation was noted during a median follow-up of 27 months (range 8 - 37 months). Our findings indicate that the RIC technique can be applied safely and effectively to various sites in the colon, avoiding the need for reoperation.

Balloon dilation of the cartilaginous portion of the eustachian tube: initial safety and feasibility analysis in a cadaver model.

PubMed

Poe, Dennis S; Hanna, Bassem Matta Nashed

2011-01-01

Balloon catheter dilation of diseased sinus ostia has recently demonstrated efficacy and safety in the treatment of chronic sinus disease with 2 years of follow-up. Similar to sinus surgery, initial studies of partial resection of inflamed mucosa from within the cartilaginous eustachian tube (ET) have demonstrated efficacy and safety in the treatment of medically refractory otitis media with effusion. Therefore, balloon dilation of the cartilaginous ET was investigated as a possible treatment modality for otitis media. A protocol for sinus balloon catheter dilation was evaluated in each of the cartilaginous ETs in 8 fresh human cadaver heads. Computed tomographic scans and detailed endoscopic inspections with video or photographic documentation were performed pre- and posttreatment, and gross anatomical dissections were done to analyze the effects of treatment and to look for evidence of undesired injury. Catheters successfully dilated all cartilaginous ETs without any significant injuries. There were no bony or cartilaginous fractures, and 3 specimens showed minor mucosal tears in the anterolateral or inferior walls. Volumetric measurements of the cartilaginous ET lumens showed a change from an average of 0.16 to 0.49 cm(3) (SD, 0.12), representing an average increase of 357% (range, 20-965%). Balloon catheter dilation of the nasopharyngeal orifice of the ET was shown to be feasible and without evidence of untoward injury. A significant increase in volume of the cartilaginous ET was achieved. A clinical study is now indicated to determine whether balloon dilation will demonstrate lasting benefits and safety in the treatment of otitis media. Copyright © 2011 Elsevier Inc. All rights reserved.

Endoscopic findings and treatment outcome in cases presenting with dysphagia.

PubMed

Hafeez, Muhammad; Salamat, Amjad; Saeed, Farrukh; Zafar, Hafiz; Hassan, Fayyaz; Farooq, Asif

2011-01-01

Dysphagia results from impeded transport of liquids, solids, or both from the pharynx to the stomach. Among the malignant lesions, carcinoma of oesophagus is the commonest cause. Our objective was to find out the frequency of different endoscopic lesions and outcome of the endoscopic therapeutic interventions in patients presenting with dysphagia. This descriptive study was conducted at Department of Gastroenterology, Military Hospital Rawalpindi from June 2008 to May 2009. Patients of dysphagia after their consent were interviewed about the symptoms. Relevant biochemical investigations were done. Barium swallow and upper Gastrointestinal (GI) Endoscopy were carried out. Benign strictures were dilated with Savary Gilliard Dilators. Malignant strictures were further evaluated to decide treatment plan. In patients considered to have oesophageal dysmotility, pressure manometery was done before specific therapy. Seventy nine patients were enrolled. Twenty-five had malignant strictures, out of those commonest was adenocarcinoma 14 (56%). Twenty-nine had benign strictures the commonest being Gastro-oesophageal Reflux Disease (GERD) related peptic stricture 9 (31%). Fifteen had oesophageal dysmotility, and achalasia was present in 10 out of them. After evaluation 12 out of 25 patients with malignant strictures were considered fit for surgery. Self-expanding metal stents (SEMS) were passed in 5. All benign strictures were dilated with Savary-Gillard dilators. Pneumatic balloon dilation was done in patients of achalasia. The commonest malignant lesion resulting in dysphagia was adenocarcinoma while in benign it was GERD related peptic stricture. Achalasia was most frequent in oesophageal motility disorders. Standard of treatment for early oesophageal malignancy is surgical resection. SEMS is a reliable way to allay dysphagia in inoperable cases. Savary Gillard dilatation in benign, and pneumatic balloon achalasia dilatations are effective ways of treatment.

Characterization of muscarinic receptors mediating relaxation and contraction in the rat iris dilator muscle.

PubMed Central

Masuda, Y; Yamahara, N S; Tanaka, M; Ryang, S; Kawai, T; Imaizumi, Y; Watanabe, M

1995-01-01

1. The characteristics of muscarinic receptors mediating relaxation and/or contraction in the rat iris dilator muscle were examined. 2. Relaxation was induced in a dilator muscle by application of acetylcholine (ACh) at low doses (3 microM or less) and contraction was induced by high doses. Methacholine and carbachol also showed biphasic effects similar to those of ACh; in contrast, bethanechol, arecoline, pilocarpine and McN-A-343 induced mainly relaxation but no substantial contraction. 3. After parasympathetic denervation by ciliary ganglionectomy, the relaxant response to muscarinic agonists disappeared upon nerve stimulation. Application of McN-A-343 and pilocarpine induced only small contractions in denervated dilator muscles, indicating that these are partial agonists for contraction. 4. pA2 values of pirenzepine, methoctramine, AF-DX 116, himbacine, and 4-DAMP for antagonism to pilocarpine-induced relaxation in normal dilator muscles and those for antagonism to ACh-induced contraction in denervated dilator muscles were determined. The pA2 values for antagonism to relaxation of all these antagonists were most similar to those for M3-type muscarinic receptors. 5. Although pA2 values for contraction of these antagonists, except for methoctramine, were very close to those for relaxation, contraction was not significantly antagonized by methoctramine. Contraction might be mediated by M3-like receptors which have a very low affinity for methoctramine. 6. In conclusion, ACh-induced biphasic responses in rat iris dilator muscles were clearly distinguished from each other by specific muscarinic agonists and parasympathetic denervation, whereas muscarinic receptors could not be subclassified according to the pA2 values of 5 specific antagonists only. PMID:7539696

Effects of intranasal oxytocin on pupil dilation indicate increased salience of socioaffective stimuli.

PubMed

Prehn, Kristin; Kazzer, Philipp; Lischke, Alexander; Heinrichs, Markus; Herpertz, Sabine C; Domes, Gregor

2013-06-01

To investigate the mechanisms by which oxytocin improves socioaffective processing, we measured behavioral and pupillometric data during a dynamic facial emotion recognition task. In a double-blind between-subjects design, 47 men received either 24 IU intranasal oxytocin (OXT) or a placebo (PLC). Participants in the OXT group recognized all facial expressions at lower intensity levels than did participants in the PLC group. Improved performance was accompanied by increased task-related pupil dilation, indicating an increased recruitment of attentional resources. We also found increased pupil dilation during the processing of female compared with male faces. This gender-specific stimulus effect diminished in the OXT group, in which pupil size specifically increased for male faces. Results suggest that improved emotion recognition after OXT treatment might be due to an intensified processing of stimuli that usually do not recruit much attention. Copyright © 2013 Society for Psychophysiological Research.

Usefulness of sugammadex in a patient with Becker muscular dystrophy and dilated cardiomyopathy.

PubMed

Shimauchi, Tsukasa; Yamaura, Ken; Sugibe, Sayaka; Hoka, Sumio

2014-09-01

A 54-year-old patient with Becker muscular dystrophy and dilated cardiomyopathy underwent laparoscopic cholecystectomy under total intravenous anesthesia. Muscle relaxation was induced by rocuronium (0.4 mg/kg body weight) under train-of-four (TOF) ratio monitoring. The TOF ratio was 0 at intubation, and 0.2 at the end of surgery. Residual muscle relaxant activity was successfully reversed by sugammadex (2 mg/kg body weight) without any hemodynamic adverse effects (TOF ratio 1.0 at extubation). The clinical and hemodynamic findings suggest that sugammadex can be safely used in patients with Becker muscular dystrophy and dilated cardiomyopathy. Copyright © 2014. Published by Elsevier B.V.

Azithromycin induced hepatocellular toxicity and hepatic encephalopathy in asymptomatic dilated cardiomyopathy

PubMed Central

Das, Bidyut Kumar

2011-01-01

Azithromycin is a widely used macrolide derivative and has generally been considered to be a very safe medication. Though gastrointestinal symptoms and reversible hearing loss are common, potentially serious side effects including angioedema and cholestatic jaundice occurred in less than one percent of patients. We report a case of asymptomatic dilated cardiomyopathy with Azithromycin induced severe hepatocellular toxicity and hepatic encephalopathy. PMID:22144789

The effect of dilatancy on the unloading behavior of Mt. Helen tuff

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

Attia, A.V.; Rubin, M.B.

1993-11-01

In order to understand the role of rock dilatancy in modeling the response of partially saturated rock formations to underground nuclear explosions, we have developed a thermodynamically consistent model for a porous material, partially saturated with fluid. This model gives good predictions of the unloading behavior of dry, partially saturated, and fully saturated Mt. Helen tuff, as measured by Heard.

Novel mathematical algorithm for pupillometric data analysis.

PubMed

Canver, Matthew C; Canver, Adam C; Revere, Karen E; Amado, Defne; Bennett, Jean; Chung, Daniel C

2014-01-01

Pupillometry is used clinically to evaluate retinal and optic nerve function by measuring pupillary response to light stimuli. We have developed a mathematical algorithm to automate and expedite the analysis of non-filtered, non-calculated pupillometric data obtained from mouse pupillary light reflex recordings, obtained from dynamic pupillary diameter recordings following exposure of varying light intensities. The non-filtered, non-calculated pupillometric data is filtered through a low pass finite impulse response (FIR) filter. Thresholding is used to remove data caused by eye blinking, loss of pupil tracking, and/or head movement. Twelve physiologically relevant parameters were extracted from the collected data: (1) baseline diameter, (2) minimum diameter, (3) response amplitude, (4) re-dilation amplitude, (5) percent of baseline diameter, (6) response time, (7) re-dilation time, (8) average constriction velocity, (9) average re-dilation velocity, (10) maximum constriction velocity, (11) maximum re-dilation velocity, and (12) onset latency. No significant differences were noted between parameters derived from algorithm calculated values and manually derived results (p ≥ 0.05). This mathematical algorithm will expedite endpoint data derivation and eliminate human error in the manual calculation of pupillometric parameters from non-filtered, non-calculated pupillometric values. Subsequently, these values can be used as reference metrics for characterizing the natural history of retinal disease. Furthermore, it will be instrumental in the assessment of functional visual recovery in humans and pre-clinical models of retinal degeneration and optic nerve disease following pharmacological or gene-based therapies. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Efficacy of incisional gastropexy for prevention of GDV in dogs.

PubMed

Benitez, Marian E; Schmiedt, Chad W; Radlinsky, MaryAnn G; Cornell, Karen K

2013-01-01

Incisional gastropexy (IG) is routinely performed as either a prophylactic procedure to prevent occurrence of gastric dilatation-volvulus (GDV) or at the time of surgical correction of GDV to prevent recurrence. Despite its common use, the long-term efficacy of the IG procedure has not been reported. The hypothesis of this study was that IG performed either during surgical treatment of GDV or as a prophylactic measure would effectively prevent GDV. Medical records of 61 dogs undergoing IG following either gastric derotation for treatment of GDV or as a prophylactic procedure were evaluated retrospectively. Median follow-up time for all dogs was 717 days (range, 49-2,511 days). Of the 61 dogs, 27 had prophylactic IG performed. The remaining 34 dogs presented for GDV and had an IG performed during surgical treatment of GDV. No dog experienced GDV after IG. Recurrence of gastric dilatation (GD) alone was noted in 3 of 34 patients (8.8%) undergoing IG during surgery for GDV and in 3 of 27 patients (11.1%) treated prophylactically with IG. This study confirmed the efficacy of IG for the long-term prevention of GDV in dogs.

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.

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

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.

Comparison between intravenous paracetamol and fentanyl for intraoperative and postoperative pain relief in dilatation and evacuation: Prospective, randomized interventional trial.

PubMed

Ali, Muhammad Asghar; Shamim, Faisal; Chughtai, Shakaib

2015-01-01

Dilatation and Evacuation procedure involves pain, for which pain control measures need to be undertaken. The purpose of this study was to compare paracetamol with fentanyl for pain relief in dilatation and curettage procedures. Sixty female patients were randomly included during the period from March 1, 2012 to February 28, 2013. All patients had received oral midazolam 7.5 mg as a premedication 30 min before procedure in the ward. Group P had received intravenous (IV) paracetamol 15 mg/kg in the waiting area of the operating room 15 min before starting the procedure. Group F had received IV fentanyl 2 ug/kg/min at induction of anesthesia. Pain scores on a numerical rating scale at 5, 15, and 30 min intervals after surgery were recorded. Mild pain was commonly observed in both groups, an insignificant difference between groups. The study demonstrates the usefulness of IV paracetamol which may be as effective as fentanyl in dilation and curettage procedures.

Comparison of implosion core metrics: A 10 ps dilation X-ray imager vs a 100 ps gated microchannel plate [Comparison of implosion core shape observations, 10 ps dilation X-ray imager vs 100 ps gated microchannel plate

DOE PAGES

Nagel, S. R.; Benedetti, L. R.; Bradley, D. K.; ...

2016-08-05

The dilation x-ray imager (DIXI) is a high-speed x-ray framing camera that uses the pulse-dilation technique to achieve a temporal resolution of less than 10 ps. This is a 10× improvement over conventional framing cameras currently employed on the National Ignition Facility (NIF) (100 ps resolution), and otherwise only achievable with 1D streaked imaging. A side effect of the dramatically reduced gate width is the comparatively lower detected signal level. Therefore we implement a Poisson noise reduction with non-local principal component analysis method to improve the robustness of the DIXI data analysis. Furthermore, we present results on ignition-relevant experiments atmore » the NIF using DIXI. In particular we focus on establishing that/when DIXI gives reliable shape metrics (P 0, P 2 and P 4 Legendre modes, and their temporal evolution/swings).« less

Comparison of implosion core metrics: A 10 ps dilation X-ray imager vs a 100 ps gated microchannel plate [Comparison of implosion core shape observations, 10 ps dilation X-ray imager vs 100 ps gated microchannel plate

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

Nagel, S. R.; Benedetti, L. R.; Bradley, D. K.

The dilation x-ray imager (DIXI) is a high-speed x-ray framing camera that uses the pulse-dilation technique to achieve a temporal resolution of less than 10 ps. This is a 10× improvement over conventional framing cameras currently employed on the National Ignition Facility (NIF) (100 ps resolution), and otherwise only achievable with 1D streaked imaging. A side effect of the dramatically reduced gate width is the comparatively lower detected signal level. Therefore we implement a Poisson noise reduction with non-local principal component analysis method to improve the robustness of the DIXI data analysis. Furthermore, we present results on ignition-relevant experiments atmore » the NIF using DIXI. In particular we focus on establishing that/when DIXI gives reliable shape metrics (P 0, P 2 and P 4 Legendre modes, and their temporal evolution/swings).« less

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.

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.

Impact of pregnancy on autograft dilatation and aortic valve function following the Ross procedure.

PubMed

Carvajal, Horacio G; Lindley, Kathryn J; Shah, Trupti; Brar, Anoop K; Barger, Philip M; Billadello, Joseph J; Eghtesady, Pirooz

2018-03-01

The effects of pregnancy on autograft dilatation and neoaortic valve function in patients with a Ross procedure have not been studied. We sought to evaluate the effect of pregnancy on autograft dilatation and valve function in these patients with the goal of determining whether pregnancy is safe after the Ross procedure. A retrospective chart review of female patients who underwent a Ross procedure was conducted. Medical records for 51 patients were reviewed. Among the 33 patients who met inclusion criteria, 11 became pregnant after surgery and 22 did not. Echocardiographic reports were used to record aortic root diameter and aortic insufficiency before, during, and after pregnancy. Patient's charts were reviewed for reinterventions and complications. Primary endpoints included reinterventions, aortic root dilation of ≥5 cm, aortic insufficiency degree ≥ moderate, and death. There were 18 pregnancies carried beyond 20 weeks in 11 patients. There was no significant difference in aortic root diameter between nulliparous patients and parous patients prior to their first pregnancy (3.53 ± 0.44 vs 3.57 ± 0.69 cm, P = .74). There was no significant change in aortic root diameter after first pregnancy (3.7 ± 0.4 cm, P = .056) although there was significant dilatation after the second (4.3 ± 0.7 cm, P = .009) and third (4.5 ± 0.7 cm, P = .009) pregnancies. Freedom from combined endpoints was significantly higher for patients in the pregnancy group than those in the nonpregnancy group (P = .002). Pregnancy was not associated with significantly increased adverse events in patients following the Ross procedure. Special care should be taken after the first pregnancy, as multiparity may lead to increased neoaortic dilatation. © 2017 Wiley Periodicals, Inc.

Long term impact of balloon post-dilatation on neointimal formation: an experimental comparative study between second-generation self-expanding versus balloon-expandable stent technologies.

PubMed

Aboodi, Michael S; Milewski, Krzysztof; Tellez, Armando; Cheng, Yanping; Yi, Geng-Hua; Kaluza, Greg L; Granada, Juan F

2014-02-15

Background: Self-expanding stents (SES) are reemerging as therapeutic alternatives to treat coronary artery disease. It has been proposed that SES can improve clinical outcomes by inducing less injury at implantation and achieving better vessel wall apposition.To date, little data exists comparing the vascular response to both methods of deployment in a controlled experimental setting. Objective: To quantify differences in vascular injury and healing between second-generation SES and balloon-expandable stents (BES) and the effects of balloon post-dilatation in a porcine coronary model. Methods: Seventy-five bare SES (AXXESS or vProtect) and 42 BES (Vision) were implanted in porcine coronaries. A subset of these received balloon post-dilatation(SES 1 D 5 22, BES 1 D 5 20). Follow-up was scheduled at 30 (BES 5 10, BES 1 D 56, SES 5 19, SES 1 D 5 8), 90 (BES 5 6, BES 1 D 5 8, SES 5 19, SES 1 D 5 8), and 180 days (BES 5 6, BES 1 D 5 6, SES 5 15, SES 1 D 5 6). Results: In vivo imaging and histological analysis showed that neointimal formation peaks early (30 days) in BES. Conversely, for SES, the peak occurred later (90 days). However, the neointimal formation achieved in either group equalized at 180 days. For SES, post-dilatation shortened the peak of neointimal formation to 30 days. Conversely, for BES, post-dilatation delayed the peak of neointimal formation to 90 days. At 30 days, histology showed that SES had significantly less injury. However, at 90 days, injury scores tended to be higher for SES. By 180 days, injury scores were comparable between both groups. Conclusions: The mechanism of stent expansion influences the degree of vascular injury and healing. The synergistic use of balloon post dilatation changes the dynamics of healing and may impact the potential beneficial effects inherent to SES technologies.

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.

Atrioventricular valve repair in patients with functional single-ventricle physiology: impact of ventricular and valve function and morphology on survival and reintervention.

PubMed

Honjo, Osami; Atlin, Cori R; Mertens, Luc; Al-Radi, Osman O; Redington, Andrew N; Caldarone, Christopher A; Van Arsdell, Glen S

2011-08-01

This study was to determine whether atrioventricular valve repair modifies natural history of single-ventricle patients with atrioventricular valve insufficiency and to identify factors predicting survival and reintervention. Fifty-seven (13.5%) of 422 single-ventricle patients underwent atrioventricular valve repair. Valve morphology, regurgitation mechanism, and ventricular morphology and function were analyzed for effect on survival, transplant, and reintervention with multivariate logistic and Cox regression models. Comparative analysis used case-matched controls. Atrioventricular valve was tricuspid in 67% and common in 28%. Ventricular morphology was right in 83%. Regurgitation mechanisms were prolapse (n = 24, 46%), dysplasia (n = 18, 35%), annular dilatation (n = 8, 15%), and restriction or cleft (n = 2, 4%). Postrepair insufficiency was none or trivial in 14 (26%), mild in 33 (61%), and moderate in 7 (13%). Survival in repair group was lower than in matched controls (78.9% vs 92.7% at 1 year, 68.7% vs 90.6% at 3 years, P = .015). Patients with successful repair and normal ventricular function had equivalent survival to matched controls (P = .36). Independent predictors for death or transplant included increased indexed annular size (P = .05), increased cardiopulmonary bypass time (P = .04), and decreased postrepair ventricular function (P = .01). Ventricular dilation was a time-related factor for all events, including failed repair. Survival was lower in single-ventricle patients operated on for atrioventricular valve insufficiency than in case-matched controls. Patients with little postoperative residual regurgitation and preserved ventricular function had equivalent survival to controls. Lower grade ventricular function and ventricular dilation correlated with death and repair failure, suggesting that timing of intervention may affect outcome. Copyright © 2011 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

Effects of structural injure in the bile bacterial contamination after balloon transduodenal sphincteroplasty (papillary dilation) in dogs.

PubMed

Zavadinack Netto, Martin; Fagundes, Djalma José; Bandeira, César Orlando Peralta

2006-01-01

To evaluate, in dogs, the biliary sphincter subjected to dilation by hydrostatic balloon by the point of view of structural alterations of the papilla and the biochemestry and bacterial contamination of the bile. Twenty dogs were submitted to laparotomy, duodenotomy, and enlargement of the major duodenal papilla- GA(n=10) - with balloon of 8mm inflated with pressure of 0,5 atm, during 2 minutes or to the sham procedure - GB(n=10). Blood samples collected on times t(0 day), t(7 days) and t(28 days) were subjected to dosages of alkaline phosphatase (ALP) and gamma-glutamyltransferase (GGT) for cholestasis evaluation. The collected material from the gall bladder at the same times were registered and numbered to be submitted to culture in BHI, blood agar (rich, non-selective element) and Mac Conkey (selective element for Gram-negative bacillus. On the 28th day three fragments of the papilla were tranversally cut by the choledoc axis 3mm from the duodenal papilla and the cuts, stained with hematoxylin-eosin and Masson's tricome, were evaluated according to their inflammatory reaction. The GGT and ALP averages on the three periods in the groups A and B did not show significant differences, not being characterizes the cholestasis. The bacterian contamination was significantly higher in GA (2,19) than in GB (1,96); the contamination was lower in the initial time compared with 7 and 28 days (t0

A Classical Based Derivation of Time Dilation Providing First Order Accuracy to Schwarzschild's Solution of Einstein's Field Equations

NASA Astrophysics Data System (ADS)

Austin, Rickey W.

In Einstein's theory of Special Relativity (SR), one method to derive relativistic kinetic energy is via applying the classical work-energy theorem to relativistic momentum. This approach starts with a classical based work-energy theorem and applies SR's momentum to the derivation. One outcome of this derivation is relativistic kinetic energy. From this derivation, it is rather straight forward to form a kinetic energy based time dilation function. In the derivation of General Relativity a common approach is to bypass classical laws as a starting point. Instead a rigorous development of differential geometry and Riemannian space is constructed, from which classical based laws are derived. This is in contrast to SR's approach of starting with classical laws and applying the consequences of the universal speed of light by all observers. A possible method to derive time dilation due to Newtonian gravitational potential energy (NGPE) is to apply SR's approach to deriving relativistic kinetic energy. It will be shown this method gives a first order accuracy compared to Schwarzschild's metric. The SR's kinetic energy and the newly derived NGPE derivation are combined to form a Riemannian metric based on these two energies. A geodesic is derived and calculations compared to Schwarzschild's geodesic for an orbiting test mass about a central, non-rotating, non-charged massive body. The new metric results in high accuracy calculations when compared to Einsteins General Relativity's prediction. The new method provides a candidate approach for starting with classical laws and deriving General Relativity effects. This approach mimics SR's method of starting with classical mechanics when deriving relativistic equations. As a compliment to introducing General Relativity, it provides a plausible scaffolding method from classical physics when teaching introductory General Relativity. A straight forward path from classical laws to General Relativity will be derived. This derivation provides a minimum first order accuracy to Schwarzschild's solution to Einstein's field equations.

Vaginismus Treatment: Clinical Trials Follow Up 241 Patients.

PubMed

Pacik, Peter T; Geletta, Simon

2017-06-01

Vaginismus is mostly unknown among clinicians and women. Vaginismus causes women to have fear, anxiety, and pain with penetration attempts. To present a large cohort of patients based on prior published studies approved by an institutional review board and the Food and Drug Administration using a comprehensive multimodal vaginismus treatment program to treat the physical and psychologic manifestations of women with vaginismus and to record successes, failures, and untoward effects of this treatment approach. Assessment of vaginismus included a comprehensive pretreatment questionnaire, the Female Sexual Function Index (FSFI), and consultation. All patients signed a detailed informed consent. Treatment consisted of a multimodal approach including intravaginal injections of onabotulinumtoxinA (Botox) and bupivacaine, progressive dilation under conscious sedation, indwelling dilator, follow-up and support with office visits, phone calls, e-mails, dilation logs, and FSFI reports. Logs noting dilation progression, pain and anxiety scores, time to achieve intercourse, setbacks, and untoward effects. Post-treatment FSFI scores were compared with preprocedure scores. One hundred seventy-one patients (71%) reported having pain-free intercourse at a mean of 5.1 weeks (median = 2.5). Six patients (2.5%) were unable to achieve intercourse within a 1-year period after treatment and 64 patients (26.6%) were lost to follow-up. The change in the overall FSFI score measured at baseline, 3 months, 6 months, and 1 year was statistically significant at the 0.05 level. Three patients developed mild temporary stress incontinence, two patients developed a short period of temporary blurred vision, and one patient developed temporary excessive vaginal dryness. All adverse events resolved by approximately 4 months. One patient required retreatment followed by successful coitus. A multimodal program that treated the physical and psychologic aspects of vaginismus enabled women to achieve pain-free intercourse as noted by patient communications and serial female sexual function studies. Further studies are indicated to better understand the individual components of this multimodal treatment program. Pacik PT, Geletta S. Vaginismus Treatment: Clinical Trials Follow Up 241 Patients. Sex Med 2017;5:e114-e123. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Galaxy power-spectrum responses and redshift-space super-sample effect

NASA Astrophysics Data System (ADS)

Li, Yin; Schmittfull, Marcel; Seljak, Uroš

2018-02-01

As a major source of cosmological information, galaxy clustering is susceptible to long-wavelength density and tidal fluctuations. These long modes modulate the growth and expansion rate of local structures, shifting them in both amplitude and scale. These effects are often named the growth and dilation effects, respectively. In particular the dilation shifts the baryon acoustic oscillation (BAO) peak and breaks the assumption of the Alcock-Paczynski (AP) test. This cannot be removed with reconstruction techniques because the effect originates from long modes outside the survey. In redshift space, the long modes generate a large-scale radial peculiar velocity that affects the redshift-space distortion (RSD) signal. We compute the redshift-space response functions of the galaxy power spectrum to long density and tidal modes at leading order in perturbation theory, including both the growth and dilation terms. We validate these response functions against measurements from simulated galaxy mock catalogs. As one application, long density and tidal modes beyond the scale of a survey correlate various observables leading to an excess error known as the super-sample covariance, and thus weaken their constraining power. We quantify the super-sample effect on BAO, AP, and RSD measurements, and study its impact on current and future surveys.

Aortic elasticity indices by magnetic resonance predict progression of ascending aorta dilation.

PubMed

Aquaro, Giovanni Donato; Briatico Vangosa, Alessandra; Toia, Patrizia; Barison, Andrea; Ait-Ali, Lamia; Midiri, Massimo; Cotroneo, Antonio Raffaele; Emdin, Michele; Festa, Pierluigi

2017-04-01

Aortic distensibility and pulse-wave velocity (PWV) are under investigation as parameters by which to evaluate the indication for ascending aorta (AA) replacement. The maximum rate of systolic distension (MRSD) was proposed as a new index of aortic elasticity. The aim of this study was to assess the role of aortic elasticity parameters to predict AA growth rates in patients with AA dilation (AAD). Magnetic resonance imaging (MRI) was performed annually in 65 patients with AA dilation (median follow-up 17 months; 25-75th percentile; range 12-30 months). A significant increase in AA diameter was defined as a ≥2-mm increase. An increase in AA diameter was found in 42 (68 %) patients (AAD+ group) and absent in 20. Median increase was 0.16 (25-75th percentile; range 0.32-0.7) mm/month. The AAD+ group had a lower MRSD (4.6 ± 2.2 vs 7.4 ± 2.0, p < 0.001) but the same PWV and distensibility. MRSD showed 93.7 % specificity and 75.6 % sensitivity for prediction of increase. Patients with MRSD ≤ 6 had lower progression-free survival times (p < 0.002). After a follow-up of 4.1 years, patients who underwent surgical therapy had lower MRSD and distensibility than others. MRSD is an index of aorta elastic properties and is a valuable predictor for progression in AAD. • MRI-derived parameters of aortic wall elasticity predict progression of ascending aorta dilation. • Maximal rate of systolic distension (MRSD) was the best predictor of progression. • Patients with MRSD ≤ 6 had lower progression-free survival (PFS) times. • Patients who underwent surgical therapy had lower MRSD and distensibility. • MRI-derived parameters identify patients with fast progression of Ascending Aorta Dilation.

Dilatation by Soehendra stent retriever is feasible and effective in multiple deployment of metallic stents to malignant hilar biliary strictures.

PubMed

Kato, Hironari; Kawamoto, Hirofumi; Noma, Yasuhiro; Sonoyama, Takayuki; Tsutsumi, Koichiro; Fujii, Masakuni; Okada, Hiroyuki; Yamamoto, Kazuhide

2013-01-01

The endoscopic management of malignant hilar biliary strictures using multiple metallic stents (MS) is technically demanding, in the initial deployment of MS and the recovery from MS occlusion with deployment of multiple plastic stents (PS). We evaluated the outcomes of the application of a Soehendra stent retriever (SSR) as a dilator of intractable strictures. Fifty-nine patients with malignant hilar biliary strictures had multiple MS inserted using a partial stent-in-stent procedure. When we encountered intractable strictures, we adopted SSR to dilate the stricture and the interstice of the MS. We evaluated the success rate of MS or PS deployment after SSR application and procedural complications. Five of 59 patients (8%) were subjected to SSR application for the initial MS deployment. MS were successfully deployed in all of these patients (100%). MS occlusion was noted in 27 patients. We applied SSR to seven patients (26%) for the deployment of multiple PS after MS occlusion. In five patients (71%), successful PS deployment was achieved after the SSR application. No complications related to dilatation using SSR occurred in any patient. SSR proved to be a potent dilator of difficult strictures in the management of malignant hilar biliary strictures.

Impaired flow-induced dilation in mesenteric resistance arteries from mice lacking vimentin.

PubMed Central

Henrion, D; Terzi, F; Matrougui, K; Duriez, M; Boulanger, C M; Colucci-Guyon, E; Babinet, C; Briand, P; Friedlander, G; Poitevin, P; Lévy, B I

1997-01-01

The intermediate filament vimentin might play a key role in vascular resistance to mechanical stress. We investigated the responses to pressure (tensile stress) and flow (shear stress) of mesenteric resistance arteries perfused in vitro from vimentin knockout mice. Arteries were isolated from homozygous (Vim-/-, n = 14) or heterozygous vimentin-null mice (Vim+/-, n = 5) and from wild-type littermates (Vim+/+, n = 9). Passive arterial diameter (175+/-15 micron in Vim+/+ at 100 mmHg) and myogenic tone were not affected by the absence of vimentin. Flow-induced (0-150 microl/min) dilation (e. g., 19+/-3 micron dilation at 150 mmHg in Vim+/+) was significantly attenuated in Vim-/- mice (13+/-2 micron dilation, P < 0.01). Acute blockade of nitric oxide synthesis (NG-nitro- L-arginine, 10 microM) significantly decreased flow-induced dilation in both groups, whereas acute blockade of prostaglandin synthesis (indomethacin, 10 microM) had no significant effect. Mean blood pressure, in vivo mesenteric blood flow and diameter, and mesenteric artery media thickness or media to lumen ratio were not affected by the absence of vimentin. Thus, the absence of vimentin decreased selectively the response of resistance arteries to flow, suggesting a role for vimentin in the mechanotransduction of shear stress. PMID:9389758

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.

Direct simulation of compressible turbulence in a shear flow

NASA Technical Reports Server (NTRS)

Sarkar, S.; Erlebacher, G.; Hussaini, M. Y.

1991-01-01

The purpose of this study is to investigate compressibility effects on the turbulence in homogeneous shear flow. It is found that the growth of the turbulent kinetic energy decreases with increasing Mach number, a phenomenon similar to the reduction of turbulent velocity intensities observed in experiments on supersonic free shear layers. An examination of the turbulent energy budget shows that both the compressible dissipation and the pressure-dilatation contribute to the decrease in the growth of kinetic energy. The pressure-dilatation is predominantly negative in homogeneous shear flow, in contrast to its predominantly positive behavior in isotropic turbulence. The different signs of the pressure-dilatation are explained by theoretical consideration of the equations for the pressure variance and density variance.

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.

Influence of compressibility on the Lagrangian statistics of vorticity-strain-rate interactions.

PubMed

Danish, Mohammad; Sinha, Sawan Suman; Srinivasan, Balaji

2016-07-01

The objective of this study is to investigate the influence of compressibility on Lagrangian statistics of vorticity and strain-rate interactions. The Lagrangian statistics are extracted from "almost" time-continuous data sets of direct numerical simulations of compressible decaying isotropic turbulence by employing a cubic spline-based Lagrangian particle tracker. We study the influence of compressibility on Lagrangian statistics of alignment in terms of compressibility parameters-turbulent Mach number, normalized dilatation-rate, and flow topology. In comparison to incompressible turbulence, we observe that the presence of compressibility in a flow field weakens the alignment tendency of vorticity toward the largest strain-rate eigenvector. Based on the Lagrangian statistics of alignment conditioned on dilatation and topology, we find that the weakened tendency of alignment observed in compressible turbulence is because of a special group of fluid particles that have an initially negligible dilatation-rate and are associated with stable-focus-stretching topology.

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.

Pulmonary arterial pressure and right ventricular dilatation independently determine tricuspid valve insufficiency severity in pre-capillary pulmonary hypertension.

PubMed

De Meester, Pieter; Van De Bruaene, Alexander; Delcroix, Marion; Belmans, Ann; Herijgers, Paul; Voigt, Jens-Uwe; Budts, Werner

2012-11-01

Elevated pulmonary artery systolic pressure (PASP) causes functional tricuspid valve insufficiency (TI). However, the differential contribution of pressure load and right ventricular (RV) dilatation is not well established. The study aim was to evaluate both variables in relation to TI. A cross-sectional study was performed of consecutive transthoracic echocardiographic studies of patients with pre-capillary pulmonary hypertension (PH). Both, demographic data and echocardiographic RV parameters were reviewed. TI was graded semi-quantitatively with color Doppler flow imaging. Trend analyses for TI severity (TI grade 0/4, 1/4, 2/4, 3/4, or 4/4) were performed. A proportional odds logistic regression analysis was carried out to identify independent predictors of TI severity. Eighty-one patients (56 females, 25 males; mean age 60 +/- 15 years) with pre-capillary PH were evaluated. Patients with more severe TI had a significantly lower body mass index, a lower mean systemic blood pressure, a shorter pulmonary acceleration time, a higher tricuspid regurgitant gradient, and a more dilated right ventricle. From the echocardiographic parameters, RV dilatation (p = 0.0143) and the tricuspid regurgitant gradient (p = 0.0026) were independently related to the degree of TI. In patients with pre-capillary PH, PASP and RV dilatation were both related to the increasing severity of TI. When focusing on TI to improve the prognosis of patients with pre-capillary PH, both PASP and RV dimensions should be taken into consideration.

The effects of Y-27632 on pial microvessels during global brain ischemia and reperfusion in rabbits.

PubMed

Shintani, Noriyuki; Ishiyama, Tadahiko; Kotoda, Masakazu; Asano, Nobumasa; Sessler, Daniel I; Matsukawa, Takashi

2017-03-07

Global brain ischemia-reperfusion during propofol anesthesia provokes persistent cerebral pial constriction. Constriction is likely mediated by Rho-kinase. Cerebral vasoconstriction possibly exacerbates ischemic brain injury. Because Y-27632 is a potent Rho-kinase inhibitor, it should be necessary to evaluate its effects on cerebral pial vessels during ischemia-reperfusion period. We therefore tested the hypotheses that Y-27632 dilates cerebral pial arterioles after the ischemia-reperfusion injury, and evaluated the time-course of cerebral pial arteriolar status after the ischemia-reperfusion. Japanese white rabbits were anesthetized with propofol, and a closed cranial window inserted over the left hemisphere. Global brain ischemia was produced by clamping the brachiocephalic, left common carotid, and left subclavian arteries for 15 min. Rabbits were assigned to cranial window perfusion with: (1) artificial cerebrospinal fluid (Control group, n = 7); (2) topical infusion of Y-27632 10 -6 mol · L -1 for 30 min before the initiation of global brain ischemia (Pre group, n = 7); (3) topical infusion of Y-27632 10 -6 mol · L -1 starting 30 min before ischemia and continuing throughout the study period (Continuous group, n = 7); and, (4) topical infusion of Y-27632 10 -6 mol · L -1 starting 10 min after the ischemia and continuing until the end of the study (Post group, n = 7). Cerebral pial arterial and venule diameters were recorded 30 min before ischemia, just before arterial clamping, 10 min after clamping, and 5, 10, 20, 40, 60, 80, 100, and 120 min after unclamping. Mean arterial blood pressure and blood glucose concentration increased significantly after global brain ischemia except in the Continuous group. In the Pre and Continuous groups, topical application of Y-27632 produced dilation of large (mean 18-19%) and small (mean; 25-29%) pial arteries, without apparent effect on venules. Compared with the Control and Pre groups, arterioles were significantly dilated during the reperfusion period in the Continuous and Post groups (mean at 120 min: 5-8% in large arterioles and 11-12% in small arterioles). Y-27632 dilated cerebral pial arterioles during reperfusion. Y-27632 may enhance recovery from ischemia by preventing arteriolar vasoconstriction during reperfusion.

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.

Paracervical block for pain control in first-trimester surgical abortion: a randomized controlled trial.

PubMed

Renner, Regina-Maria; Nichols, Mark D; Jensen, Jeffrey T; Li, Hong; Edelman, Alison B

2012-05-01

Despite lack of efficacy data, the majority of first-trimester surgical abortions are performed with a paracervical block. Women may be unnecessarily exposed to a painful injection and potentially noxious medication. Our objective was to estimate the effect of a paracervical block and the effect of gestational age on patient pain perception. This was a randomized, single-blind trial of patients undergoing abortion receiving paracervical block or sham stratified by gestational age (early: less than 8 weeks of gestation, n=60; late: 8-10 6/7 weeks of gestation, n=60). Premedicated with ibuprofen and lorazepam, all participants received 2 mL 1% buffered lidocaine injected at the tenaculum site followed by a slow, deep injection of 18 mL at four sites (block) or no injection (sham) with a 3-minute wait. The primary outcome was dilation pain (100-mm visual analog scale). Secondary outcomes included pain at additional time points, satisfaction, need for more analgesics, and adverse events. Full enrollment occurred (n=120). We used intent-to-treat analysis. Demographics did not differ between groups. Paracervical block administration was painful (mean 55 mm compared with sham 30 mm, P<.001) but decreased dilation pain (42 mm compared with 79 mm, P<.001) and aspiration pain (63mm compared with 89 mm, P<.001). These results were consistent for both gestational age strata; however, paracervical block benefit was greater at an earlier gestation. Satisfaction scores with pain control and the procedure were significantly higher in the block group. Although paracervical block is painful, it reduces first-trimester abortion pain regardless of gestational age, but the benefit on dilation pain was greater at earlier gestations. ClinicalTrials.gov, www.clinicaltrials.gov, NCT01094366. I.

Dilation of the oropharynx via selective stimulation of the hypoglossal nerve

NASA Astrophysics Data System (ADS)

Huang, Jingtao; Sahin, Mesut; Durand, Dominique M.

2005-12-01

The functional effects of selective hypoglossal nerve (HG) stimulation with a multi-contact peripheral nerve electrode were assessed using images of the upper airways and the tongue in anesthetized beagles. A biphasic pulse train of 50 Hz frequency and 2 s duration was applied through each one of the tripolar contact sets of the nerve electrode while the pharyngeal images were acquired into a computer. The stimulation current was limited to 20% above the activation threshold for maximum selectivity. The images showed that various contact sets could generate several different activation patterns of the tongue muscles resulting in medial and/or lateral dilation and closing of the airways at the tongue root. Some of these patterns translated into an increase in the oropharyngeal size while others did not have any effect. The pharyngeal sizes were not statistically different during stimulation either between the two different positions of the head (30° and 60°), or when the lateral contacts were compared with the medial ones. The contacts that had the least effect generated an average of 53 ± 15% pharyngeal dilation relative to the best contacts, indicating that the results are marginally sensitive to the contact position around the HG nerve trunk. These results suggest that selective HG nerve stimulation can be a useful technique to produce multiple tongue activation patterns that can dilate the pharynx. This may in turn increase the size of the patient population who can benefit from HG nerve stimulation as a treatment method for obstructive sleep apnea.

The Frequency of Rapid Pupil Dilations as a Measure of Linguistic Processing Difficulty

PubMed Central

Demberg, Vera; Sayeed, Asad

2016-01-01

While it has long been known that the pupil reacts to cognitive load, pupil size has received little attention in cognitive research because of its long latency and the difficulty of separating effects of cognitive load from the light reflex or effects due to eye movements. A novel measure, the Index of Cognitive Activity (ICA), relates cognitive effort to the frequency of small rapid dilations of the pupil. We report here on a total of seven experiments which test whether the ICA reliably indexes linguistically induced cognitive load: three experiments in reading (a manipulation of grammatical gender match / mismatch, an experiment of semantic fit, and an experiment comparing locally ambiguous subject versus object relative clauses, all in German), three dual-task experiments with simultaneous driving and spoken language comprehension (using the same manipulations as in the single-task reading experiments), and a visual world experiment comparing the processing of causal versus concessive discourse markers. These experiments are the first to investigate the effect and time course of the ICA in language processing. All of our experiments support the idea that the ICA indexes linguistic processing difficulty. The effects of our linguistic manipulations on the ICA are consistent for reading and auditory presentation. Furthermore, our experiments show that the ICA allows for usage within a multi-task paradigm. Its robustness with respect to eye movements means that it is a valid measure of processing difficulty for usage within the visual world paradigm, which will allow researchers to assess both visual attention and processing difficulty at the same time, using an eye-tracker. We argue that the ICA is indicative of activity in the locus caeruleus area of the brain stem, which has recently also been linked to P600 effects observed in psycholinguistic EEG experiments. PMID:26799065

Histopathology of aortic complications in bicuspid aortic valve versus Marfan syndrome: relevance for therapy?

PubMed

Grewal, Nimrat; Franken, Romy; Mulder, Barbara J M; Goumans, Marie-José; Lindeman, Johannes H N; Jongbloed, Monique R M; DeRuiter, Marco C; Klautz, Robert J M; Bogers, Ad J J C; Poelmann, Robert E; Groot, Adriana C Gittenberger-de

2016-05-01

Patients with bicuspid aortic valve (BAV) and patients with Marfan syndrome (MFS) are more prone to develop aortic dilation and dissection compared to persons with a tricuspid aortic valve (TAV). To elucidate potential common and distinct pathways of clinical relevance, we compared the histopathological substrates of aortopathy. Ascending aortic wall biopsies were divided in five groups: BAV (n = 36) and TAV (n = 23) without and with dilation and non-dilated MFS (n = 8). General histologic features, apoptosis, the expression of markers for vascular smooth muscle cell (VSMC) maturation, markers predictive for ascending aortic dilation in BAV, and expression of fibrillin-1 were investigated. Both MFS and BAV showed an altered distribution and decreased fibrillin-1 expression in the aorta and a significantly lower level of differentiated VSMC markers. Interestingly, markers predictive for aortic dilation in BAV were not expressed in the MFS aorta. The aorta in MFS was similar to the aorta in dilated TAV with regard to the presence of medial degeneration and apoptosis, while other markers for degeneration and aging like inflammation and progerin expression were low in MFS, comparable to BAV. Both MFS and BAV aortas have immature VSMCs, while MFS and TAV patients have a similar increased rate of medial degeneration. However, the mechanism leading to apoptosis is expected to be different, being fibrillin-1 mutation induced increased angiotensin-receptor-pathway signaling in MFS and cardiovascular aging and increased progerin in TAV. Our findings could explain why angiotensin inhibition is successful in MFS and less effective in TAV and BAV patients.

Long-term results of pneumatic dilatation for relapsing symptoms of achalasia after Heller myotomy.

PubMed

Legros, Ludivine; Ropert, Alain; Brochard, Charlène; Bouguen, Guillaume; Pagenault, Maël; Siproudhis, Laurent; Bretagne, Jean-François

2014-09-01

The aim of this study was to assess the efficacy and safety of pneumatic dilatation (PD) to treat symptom recurrence after Heller myotomy (HM). Consecutive patients receiving PD for relapsing symptoms following prior HM were included in this retrospective single-center study. Eckardt score ≤3 and/or ∆ Eckardt (difference between Eckardt score before and after dilatation) ≥3 defined the success of initial dilatation. Patients who maintained response longer than 2 months after initial dilatation were defined as short-term responders. Relapsers were offered further on-demand dilatation. Remission was defined as an Eckardt score ≤3 at the study endpoint. Kaplan-Meier survival curves were used to determine relapse rates. Eighteen patients (11 women, seven men) were included from January 2004 to January 2013. Ten patients had type I achalasia, and seven had type III, according to the Chicago classification. Thirty-nine PDs were performed (1.5 [1-2.25] per patient). All patients had short-term responses. The remission rate at the endpoint, after a median follow-up of 33 months, was 78%, but 44% were treated with on-demand PD during the follow-up interval. The proportions of patients without relapse and subsequent PD were 72% at 12 months, 65% at 24 and 36 months, and 49% at 48 months. No factors predictive of long-term response, particularly the type of achalasia, could be identified in this series. There were no perforations. In treating symptom recurrence following HM, PD was safe and effective over the long term when combined with subsequent PD. © 2014 John Wiley & Sons Ltd.

[Combination of the ureteral dilation catheter and balloon catheter under the ureteroscope in the treatment of male urethral stricture].

PubMed

Zhou, Yi; Li, Gong-hui; Yan, Jia-jun; Shen, Cong; Tang, Gui-hang; Xu, Gang

2016-01-01

To investigate the clinical application of the ureteral dilation catheter combined with the balloon catheter under the ureteroscope in the treatment of urethral stricture in men. Under the ureteroscope, 45 male patients with urethral stricture received placement of a zebra guide wire through the strictured urethra into the bladder and then a ureteral dilation catheter along the guide wire, followed by dilation of the urethra from F8 initially to F14 and F16. Again, the ureteroscope was used to determine the length of the strictured urethra, its distance to the external urethral orifice, and whether it was normally located. An F24 balloon catheter and then a metal urethral calibrator was used for the dilation of the strictured urethra. After removal of the F18-F22 urethral catheter at 8 weeks, the urinary flow rate was measured immediately and again at 3 months. All the operations were successfully performed without serious complications. The maximum urinary flow rate was (13.3-29.9) ml/s (mean [17.7 ± 3.2] ml/s) at the removal of the catheter and (15.2-30.8) ml/s (mean [19.8 ± 3.9] ml/s) at 3 months after it. Smooth urination was found in all the patients during the 6-24 months follow-up. The application of the ureteral dilation catheter combined with, the balloon catheter under the ureteroscope is a good option for the treatment of male urethral stricture for its advantages of uncomplicatedness, safety, effectiveness, few complications, less pain, high success rate, and repeatable operation.

Influence of interfacial viscosity on the dielectrophoresis of drops

NASA Astrophysics Data System (ADS)

Mandal, Shubhadeep; Chakraborty, Suman

2017-05-01

The dielectrophoresis of a Newtonian uncharged drop in the presence of an axisymmetric nonuniform DC electric field is studied analytically. The present study is focused on the effects of interfacial viscosities on the dielectrophoretic motion and shape deformation of an isolated suspended drop. The interfacial viscosities generate surface-excess viscous stress which is modeled as a two-dimensional Newtonian fluid which obeys the Boussinesq-Scriven constitutive law with constant values of interfacial tension, interfacial shear, and dilatational viscosities. In the regime of small drop deformation, we have obtained analytical solution for the drop velocity and deformed shape by neglecting surface charge convection and fluid inertia. Our study demonstrates that the drop velocity is independent of the interfacial shear viscosity, while the interfacial dilatational viscosity strongly affects the drop velocity. The interfacial viscous effects always retard the dielectrophoretic motion of a perfectly conducting/dielectric drop. Notably, the interfacial viscous effects can retard or augment the dielectrophoretic motion of a leaky dielectric drop depending on the electrohydrodynamic properties. The shape deformation of a leaky dielectric drop is found to decrease (or increase) due to interfacial shear (or dilatational) viscosity.

Mass defect effects in atomic clocks

NASA Astrophysics Data System (ADS)

Yudin, Valeriy; Taichenachev, Alexey

2018-03-01

We consider some implications of the mass defect on the frequency of atomic transitions. We have found that some well-known frequency shifts (the gravitational shift and motion-induced shifts such as quadratic Doppler and micromotion shifts) can be interpreted as consequences of the mass defect in quantum atomic physics, i.e. without the need for the concept of time dilation used in special and general relativity theories. Moreover, we show that the inclusion of the mass defect leads to previously unknown shifts for clocks based on trapped ions.

Effect of gravitation stress and hypokinesia on blood vessels of the testicle

NASA Technical Reports Server (NTRS)

Palazhchenko, E. F.

1979-01-01

Rabbits were exposed to single maximum endurable stresses of cranio-caudal direction, hypokinesia for periods of one to eight weeks, and hypokinesia followed by gravitation stresses. The stresses caused dilatation of vessels, greater sinuosity, and occasional ruptures of the walls and extravasation. The greater part of the capillaries were dilated; the greatest part constricted. In hypokinesia there was an increasing atrophy of the testes. Significant results are reported.

13C-sodium acetate breath test for evaluation of gastric emptying times in dogs with gastric dilatation-volvulus.

PubMed

Schmitz, S; Jansen, N; Failing, K; Neiger, R

2013-01-01

The aim of the study was to assess solid phase gastric emptying via non-invasive 13C-sodium acetate breath test in large breed dogs with or without gastric dilatation-volvulus (GDV). Dogs were recruited into one of the following groups: group 1 = healthy large breed dogs with no history of GDV, group 2 = dogs that underwent elective abdominal surgery for reasons unrelated to the gastrointestinal tract, and group 3 = dogs that underwent laparotomy and gastropexy to correct GDV. The dogs were fed a test meal containing 100 mg 13C-sodium acetate (for group 2 and 3, this was < 48 hours post-operatively). Breath samples were obtained at baseline and every 30 minutes for 3 hours, then every hour for a total of 7 hours. 12CO2/13CO2 ratio was measured for each breath sample via non-dispersive infrared spectroscopy and 25%, 50% and 75% gastric emptying times were calculated and compared between groups. Gastric emptying times were significantly prolonged in dogs undergoing surgery (group 2) compared to group 1 and 3. Also, gastric emptying times of dogs with GDV were significantly prolonged compared to controls, but not to the same extent as dogs in group 2. There was a significant effect of abdominal surgery on gastric emptying times. Surprisingly, dogs after GDV surgery and gastropexy had shorter gastric emptying times than dogs undergoing laparotomy for reasons other than GDV, but still prolonged compared to healthy controls. The reason for these differences requires further study.

Influence of Contrast Agent Dilution on Ballon Deflation Time and Visibility During Tracheal Balloon Dilation: A 3D Printed Phantom Study

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

Kim, Min Tae; Park, Jung-Hoon; Shin, Ji Hoon, E-mail: jhshin@amc.seoul.kr

PurposeTo determine the effect of contrast medium dilution during tracheal balloon dilation on balloon deflation time and visibility using a 3-dimensional (3D) printed airway phantom.Materials and MethodsA comparison study to investigate balloon deflation times and image quality was performed using two contrast agents with different viscosities, i.e., iohexol and ioxithalamate, and six contrast dilutions with a 3D printed airway phantom.ResultsCompared to 1:0 concentration, 3:1, 2:1, 1:1, 1:2, and 1:3, contrast/saline ratios resulted in a 46% (56.2 s), 59.8% (73.1 s), 74.9% (91.6 s), 81.7% (99.8 s), and 83.5% (102 s) reduction for iohexol, respectively, and a 51.8% (54.7 s), 63.8% (67.6 s), 74.7% (79.2 s), 80.5% (85.3 s), andmore » 82.4% (87.4 s) reduction for ioxithalamate, respectively, in the mean balloon deflation time, although at the expense of decreased balloon opacity (3.5, 6.9, 11.1, 12.4, and 13.9%, for iohexol, respectively, and 3.2, 6, 9.6, 10.8, and 12.4%, for ioxithalamate, respectively).ConclusionsUse of a lower viscosity contrast agent and higher contrast dilution is considered to be able to reduce balloon deflation times and then simultaneously decrease visualization of balloons. The rapid balloon deflation time is likely to improve the safe performance of interventional procedures.« less

Relativity in the Global Positioning System.

PubMed

Ashby, Neil

2003-01-01

The Global Positioning System (GPS) uses accurate, stable atomic clocks in satellites and on the ground to provide world-wide position and time determination. These clocks have gravitational and motional frequency shifts which are so large that, without carefully accounting for numerous relativistic effects, the system would not work. This paper discusses the conceptual basis, founded on special and general relativity, for navigation using GPS. Relativistic principles and effects which must be considered include the constancy of the speed of light, the equivalence principle, the Sagnac effect, time dilation, gravitational frequency shifts, and relativity of synchronization. Experimental tests of relativity obtained with a GPS receiver aboard the TOPEX/POSEIDON satellite will be discussed. Recently frequency jumps arising from satellite orbit adjustments have been identified as relativistic effects. These will be explained and some interesting applications of GPS will be discussed.

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

To compare the effect of camylofin dihydrochloride (anafortin) with combination of valethamate bromide (epidosin) and hyoscine butyl-N-bormide (buscopan) on cervical dilation.

PubMed

Sarbhjit, Kaur; S K, Bajwa; Parmjit, Kaur; Surinder, Bhupal

2013-09-01

Various drugs have been tried to hasten cervical dilatation so that problems and hazards of prolonged labour both for the mother and fetus are minimised without increasing maternal or perinatal mortality and morbidity. To compare the effect of camylofin dihydrochloride with combination of valethemate bromide (epidosin) & hyoscine N butyl bromide (buscopan) on cervical dilatation, evaluate the incidence of side effects and to look for neonatal outcome. Two hundred cases were included of primigravidae or multigravidae with gestational age of 37 to 40 weeks with full term with single foetus,vertex presentation and no major antenatal complication of women in labour, admitted to labour room of gynaecology Department, Government Medical College, Patiala, India, was studied and divided into 2 groups Group A-100 Cases - labour accelerated by camylofin dihydro chloride and Group B-100 Cases-labour accelerated by valethemate bromide (epidosin) and hyoscine N butyl bromide. The mean age, parity and period of gestation in Anafortan group was 24.13 ± 3.60 years, 49% primigravidae and 51% multigravidae and 38.81 ± 1.09 weeks, while that in Epidosin + Buscopan group was 24.43 ± 3.42 years, 45% primigravidae and 51% multigravidae and 38.94 ± 1.09 weeks respectively. The difference was insignificant and both the groups were comparable. Mean duration of Active phase of 1st stage of labor was 141.40 ± 55.41 minutes in Anafortan group and 181.46 ± 75.58 minutes in Epidosin + Buscopan group. Mean rate of cervical dilatation according to active phase of first stage was 3.33 ± 1.03 cm/hours in Anafortan group and 2.69 ± 1.03 cm/hr in Epidosin + Buscopan group. The difference between the two groups is highly significant (p < 0.01) thus it is concluded that Anafortan hastened the rate of cervical dilatation.

To Compare the Effect of Camylofin Dihydrochloride (Anafortin) with Combination of Valethamate Bromide (Epidosin) and Hyoscine Butyl-N-Bormide (Buscopan) on Cervical Dilation

PubMed Central

Sarbhjit, Kaur; S.K., Bajwa; Parmjit, Kaur; Surinder, Bhupal

2013-01-01

Background: Various drugs have been tried to hasten cervical dilatation so that problems and hazards of prolonged labour both for the mother and fetus are minimised without increasing maternal or perinatal mortality and morbidity. Aims and Objectives: To compare the effect of camylofin dihydrochloride with combination of valethemate bromide (epidosin) & hyoscine N butyl bromide (buscopan) on cervical dilatation, evaluate the incidence of side effects and to look for neonatal outcome. Material and Methods: Two hundred cases were included of primigravidae or multigravidae with gestational age of 37 to 40 weeks with full term with single foetus,vertex presentation and no major antenatal complication of women in labour, admitted to labour room of gynaecology Department, Government Medical College, Patiala, India, was studied and divided into 2 groups Group A–100 Cases – labour accelerated by camylofin dihydro chloride and Group B–100 Cases–labour accelerated by valethemate bromide (epidosin) and hyoscine N butyl bromide. Observations: The mean age, parity and period of gestation in Anafortan group was 24.13 ± 3.60 years, 49% primigravidae and 51% multigravidae and 38.81 ± 1.09 weeks, while that in Epidosin + Buscopan group was 24.43 ± 3.42 years, 45% primigravidae and 51% multigravidae and 38.94 ± 1.09 weeks respectively. The difference was insignificant and both the groups were comparable. Results: Mean duration of Active phase of 1st stage of labor was 141.40 ± 55.41 minutes in Anafortan group and 181.46 ± 75.58 minutes in Epidosin + Buscopan group. Mean rate of cervical dilatation according to active phase of first stage was 3.33 ± 1.03 cm/hours in Anafortan group and 2.69 ± 1.03 cm/hr in Epidosin + Buscopan group. The difference between the two groups is highly significant (p < 0.01) thus it is concluded that Anafortan hastened the rate of cervical dilatation. PMID:24179892

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.

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.

The efficacy of balloon dilation in achalasia is the result of stretching of the lower esophageal sphincter, not muscular disruption.

PubMed

Borhan-Manesh, F; Kaviani, M J; Taghavi, A R

2016-04-01

Pneumatic dilation (PD) of the lower esophageal sphincter (LES) in achalasia is a major palliative treatment. It is generally believed, although never substantiated, that therapeutic efficacy of ballooning in achalasia is the result of the disruption and tearing of the muscular layers of the LES. To clarify this issue, we investigated the frequency of muscular disruption at the LES, 24 hours after PD, by employing the endoscopic ultrasound (EUS), in a group of 43 consented patients with achalasia. Between July 2009 and March2012, 51 consecutive adult patients with tentative diagnosis of achalasia, some with recurrence of symptoms after an earlier treatment with balloon dilation, were evaluated and underwent PD, using Rigiflex balloon without major adverse effect. Out of the 51 evaluated, 43 eligible and consenting patients who underwent EUS, 24 hours after PD, using Olympus GF-UE 160 echoendoscope and an Aloka Prosound probe at 7.5 MHZ, are the subjects of this study. The EUS in 43 eligible patients revealed an intact LES in 36 (83.7%), small area of muscular disruption in 5 (11.6%) and small hematoma in 2 patients (4.6%). Our data convincingly demonstrate that the clinical effectiveness of balloon dilation in achalasia is not the result of muscular disruption, but of circumferential stretching of the LES. Our findings on the mechanism of action of PD in achalasia could result in modifying the current method of dilation for a safer procedure, by slowing the rate of inflation and allowing the sphincter to slowly stretch itself to the distending balloon. © 2015 The Authors. Diseases of the Esophagus published by Wiley Periodicals, Inc. on behalf of International Society for Diseases of the Esophagus.

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 ...

On the theory of time dilation in chemical kinetics

NASA Astrophysics Data System (ADS)

Baig, Mirza Wasif

2017-10-01

The rates of chemical reactions are not absolute but their magnitude depends upon the relative speeds of the moving observers. This has been proved by unifying basic theories of chemical kinetics, which are transition state theory, collision theory, RRKM and Marcus theory, with the special theory of relativity. Boltzmann constant and energy spacing between permitted quantum levels of molecules are quantum mechanically proved to be Lorentz variant. The relativistic statistical thermodynamics has been developed to explain quasi-equilibrium existing between reactants and activated complex. The newly formulated Lorentz transformation of the rate constant from Arrhenius equation, of the collision frequency and of the Eyring and Marcus equations renders the rate of reaction to be Lorentz variant. For a moving observer moving at fractions of the speed of light along the reaction coordinate, the transition state possess less kinetic energy to sweep translation over it. This results in the slower transformation of reactants into products and in a stretched time frame for the chemical reaction to complete. Lorentz transformation of the half-life equation explains time dilation of the half-life period of chemical reactions and proves special theory of relativity and presents theory in accord with each other. To demonstrate the effectiveness of the present theory, the enzymatic reaction of methylamine dehydrogenase and radioactive disintegration of Astatine into Bismuth are considered as numerical examples.

Nanoparticle inhalation alters systemic arteriolar vasoreactivity through sympathetic and cyclooxygenase-mediated pathways

PubMed Central

Knuckles, Travis L.; Yi, Jinghai; Frazer, David G.; Leonard, Howard D.; Chen, Bean T.; Castranova, Vince; Nurkiewicz, Timothy R.

2016-01-01

The widespread increase in the production and use of nanomaterials has increased the potential for nanoparticle exposure; however, the biological effects of nanoparticle inhalation are poorly understood. Rats were exposed to nanosized titanium dioxide aerosols (10 µg lung burden); at 24 h post-exposure, the spinotrapezius muscle was prepared for intravital microscopy. Nanoparticle exposure did not alter perivascular nerve stimulation (PVNS)-induced arteriolar constriction under normal conditions; however, adrenergic receptor inhibition revealed a more robust effect. Nanoparticle inhalation reduced arteriolar dilation in response to active hyperaemia (AH). In both PVNS and AH experiments, nitric oxide synthase (NOS) inhibition affected only controls. Whereas cyclooxygenase (COX) inhibition only attenuated AH-induced arteriolar dilation in nanoparticle-exposed animals. This group displayed an enhanced U46619 constriction and attenuated iloprost-induced dilation. Collectively, these studies indicate that nanoparticle exposure reduces microvascular NO bioavailability and alters COX-mediated vasoreactivity. Furthermore, the enhanced adrenergic receptor sensitivity suggests an augmented sympathetic responsiveness. PMID:21830860

Analysis of embolic signals with directional dual tree rational dilation wavelet transform.

PubMed

Serbes, Gorkem; Aydin, Nizamettin

2016-08-01

The dyadic discrete wavelet transform (dyadic-DWT), which is based on fixed integer sampling factor, has been used before for processing piecewise smooth biomedical signals. However, the dyadic-DWT has poor frequency resolution due to the low-oscillatory nature of its wavelet bases and therefore, it is less effective in processing embolic signals (ESs). To process ESs more effectively, a wavelet transform having better frequency resolution than the dyadic-DWT is needed. Therefore, in this study two ESs, containing micro-emboli and artifact waveforms, are analyzed with the Directional Dual Tree Rational-Dilation Wavelet Transform (DDT-RADWT). The DDT-RADWT, which can be directly applied to quadrature signals, is based on rational dilation factors and has adjustable frequency resolution. The analyses are done for both low and high Q-factors. It is proved that, when high Q-factor filters are employed in the DDT-RADWT, clearer representations of ESs can be attained in decomposed sub-bands and artifacts can be successfully separated.

An Assessment of the Effects of Hydrotherapy During the Active Phase of Labor on the Labor Process and Parenting Behavior.

PubMed

Tuncay, Semra; Kaplan, Sena; Moraloglu Tekin, Ozlem

2017-12-01

This study was conducted to assess the effect on labor process and parenting behavior of hydrotherapy applied during the active phase of labor. This quasi-experimental study was conducted by using an equivalent comparison group ( n = 40). The participants in the experimental group whose cervical dilation was 5 cm were taken to the hydrotherapy tub. This application continued until cervical dilation reached 10 cm. The Participants Questionnaire, The Birth Follow-up Questionnaire, The Postpartum ]collection tools. The duration of the active phase and second stage of labor was extremely short in the experimental group in comparison with the equivalent comparison group ( p = .001). The Visual Analogue Scale (VAS) scores of the experimental group were lower than those of the equivalent comparison group when cervical dilation was 6 cm and 10 cm ( p = .001). The experimental group also displayed more positive parenting behavior and positive labor feeling ( p = .001).

Ventricular dilation as an instability of intracranial dynamics

NASA Astrophysics Data System (ADS)

Bouzerar, R.; Ambarki, K.; Balédent, O.; Kongolo, G.; Picot, J. C.; Meyer, M. E.

2005-11-01

We address the question of the ventricles’ dilation as a possible instability of the intracranial dynamics. The ventricular system is shown to be governed by a dynamical equation derived from first principles. This general nonlinear scheme is linearized around a well-defined steady state which is mapped onto a pressure-volume model with an algebraic effective compliance depending on the ventricles’ geometry, the ependyma’s elasticity, and the cerebrospinal fluid (CSF) surface tension. Instabilities of different natures are then evidenced. A first type of structural instability results from the compelling effects of the CSF surface tension and the elastic properties of the ependyma. A second type of dynamical instability occurs for low enough values of the aqueduct’s conductance. This last case is then shown to be accompanied by a spontaneous ventricle’s dilation. A strong correlation with some active hydrocephalus is evidenced and discussed. The transfer function of the ventricles, compared to a low-pass filter, are calculated in both the stable and unstable regimes and appear to be very different.

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.

Fetal intracardiac potassium chloride injection to expedite second-trimester dilation and evacuation.

PubMed

Singh, Sareena; Seligman, Neil S; Jackson, Brittany; Berghella, Vincenzo

2012-01-01

To determine whether potassium chloride (KCl)-induced feticide prior to termination by dilation and evacuation (D&E) improves surgical outcome. We conducted a retrospective study of women who underwent second-trimester (13 0/7 to 23 6/7 weeks) D&E at an urban university-based hospital between January 2000 and July 2010. Women were divided into 3 cohorts: (1) D&E for termination of pregnancy after feticide, (2) D&E without feticide, and (3) D&E for spontaneous pregnancy loss. We compared maternal characteristics, various perioperative variables, and surgical outcomes for all 3 groups. Anesthesia time was used as a surrogate for operative time in the primary outcome. We analyzed 128 pregnancies (group 1: n = 23, group 2: n = 53, group 3: n = 52). Baseline maternal characteristics did not differ among the 3 groups. Anesthesia time was longest in the termination with KCl group (group 1: 116.9 min vs. group 2: 94.5 min and group 3: 90.3 min, p = 0.004), however, the effect was mitigated after controlling for fetal size (p = 0.176). There was no difference in blood loss (p = 0.968). Complications were uncommon, however, cervical lacerations were more common in the termination with KCl group (2 vs. 0 and 0, p = 0.010). Presurgical feticide with KCl was not associated with shorter anesthesia time. The decision to perform feticide should be based on other considerations, such as patient preference. Copyright © 2011 S. Karger AG, Basel.

Direct simulation of compressible turbulence in a shear flow

NASA Technical Reports Server (NTRS)

Sarkar, S.; Erlebacher, G.; Hussaini, M. Y.

1991-01-01

Compressibility effects on the turbulence in homogeneous shear flow are investigated. The growth of the turbulent kinetic energy was found to decrease with increasing Mach number: a phenomenon which is similar to the reduction of turbulent velocity intensities observed in experiments on supersonic free shear layers. An examination of the turbulent energy budget shows that both the compressible dissipation and the pressure-dilatation contribute to the decrease in the growth of kinetic energy. The pressure-dilatation is predominantly negative in homogeneous shear flow, in contrast to its predominantly positive behavior in isotropic turbulence. The different signs of the pressure-dilatation are explained by theoretical consideration of the equations for the pressure variance and density variance. Previously, the following results were obtained for isotropic turbulence: (1) the normalized compressible dissipation is of O(M(sub t)(exp 2)); and (2) there is approximate equipartition between the kinetic and potential energies associated with the fluctuating compressible mode. Both of these results were substantiated in the case of homogeneous shear. The dilatation field is significantly more skewed and intermittent than the vorticity field. Strong compressions seem to be more likely than strong expansions.

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.

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.

The influence of women's attachment style on the chronobiology of labour pain, analgesic consumption and pharmacological effect.

PubMed

Costa-Martins, José Manuel; Pereira, Marco; Martins, Henriqueta; Moura-Ramos, Mariana; Coelho, Rui; Tavares, Jorge

2014-07-01

Circadian variation in biological rhythms has been identified as affecting both labour pain and the pharmacological properties of analgesics. In the context of pain, there is also a growing body of evidence suggesting the importance of adult attachment. The purpose of this study was to examine whether labour pain, analgesic consumption and pharmacological effect are significantly affected by the time of day and to analyse whether this circadian variation is influenced by women's attachment style. This prospective observational study included a sample of 81 pregnant women receiving patient-controlled epidural analgesia (PCEA). Attachment was assessed with the Adult Attachment Scale - Revised. The perceived intensity of labour pain in the early stage of labour (3 cm of cervical dilatation and before the administration of PCEA) was measured using a visual analogue scale (VAS). Pain was also indirectly assessed by measuring the consumption of anaesthetics. The latency period and the duration of effect were recorded for a chronopharmacology characterisation. Pain, as assessed with the VAS, was significantly higher in the night-time group than in the daytime group. An insecure attachment style was significantly associated with greater labour pain at 3 cm of cervical dilatation (p < 0.001) and before the beginning of analgesia (p < 0.001) as well as with higher analgesic consumption and lower pharmacological efficacy (p < 0.05). The time of day was significantly associated with the pharmacological effect: the latency period was longer at night, and the duration of the pharmacological effect was longer during the daytime. The interaction between time of day and attachment style was not significant for any of the study variables. Our results provide evidence of the importance of circadian variation in studying labour pain and the pharmacological effect of labour analgesia involving epidural blockage with a PCEA regimen. Moreover, although there was no evidence that attachment style influenced the circadian variation, these data emphasise that insecure attachment patterns are a risk factor for greater labour pain and analgesic consumption, which should be considered in pain management approaches.

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.

Chronic Administration of Small Nonerythropoietic Peptide Sequence of Erythropoietin Effectively Ameliorates the Progression of Postmyocardial Infarction–Dilated Cardiomyopathy

PubMed Central

Ahmet, Ismayil; Tae, Hyun-Jin; Brines, Michael; Cerami, Anthony; Lakatta, Edward G.

2013-01-01

The cardioprotective properties of erythropoietin (EPO) in preclinical studies are well documented, but erythropoietic and prothrombotic properties of EPO preclude its use in chronic heart failure (CHF). We tested the effect of long-term treatment with a small peptide sequence within the EPO molecule, helix B surface peptide (HBSP), that possesses tissue-protective, but not erythropoietic properties of EPO, on mortality and cardiac remodeling in postmyocardial infarction–dilated cardiomyopathy in rats. Starting 2 weeks after permanent left coronary artery ligation, rats received i.p. injections of HBSP (60 µg/kg) or saline two times per week for 10 months. Treatment did not elicit an immune response, and did not affect the hematocrit. Compared with untreated rats, HBSP treatment reduced mortality by 50% (P < 0.05). Repeated echocardiography demonstrated remarkable attenuation of left ventricular dilatation (end-diastolic volume: 41 versus 86%; end-systolic volume: 44 versus 135%; P < 0.05), left ventricle functional deterioration (ejection fraction: −4 versus −63%; P < 0.05), and myocardial infarction (MI) expansion (3 versus 38%; P < 0.05). A hemodynamic assessment at study termination demonstrated normal preload independent stroke work (63 ± 5 versus 40 ± 4; P < 0.05) and arterioventricular coupling (1.2 ± 0.2 versus 2.7 ± 0.7; P < 0.05). Histologic analysis revealed reduced apoptosis (P < 0.05) and fibrosis (P < 0.05), increased cardiomyocyte density (P < 0.05), and increased number of cardiomyocytes in myocardium among HBSP-treated rats. The results indicate that HBSP effectively reduces mortality, ameliorates the MI expansion and CHF progression, and preserves systolic reserve in the rat post-MI model. There is also a possibility that HBSP promoted the increase of the myocytes number in the myocardial wall remote from the infarct. Thus, HBSP peptide merits consideration for clinical testing. PMID:23584743

Distinct action of aranidipine and its active metabolite on renal arterioles, with special reference to renal protection.

PubMed

Nakamura, A; Hayashi, K; Fujiwara, K; Ozawa, Y; Honda, M; Saruta, T

2000-06-01

Aranidipine, a newly developed calcium antagonist, possesses unique pharmacologic characteristics in that its metabolite (M-1) still has antihypertensive action. We examined the effects of both agents on renal microcirculation using the isolated perfused hydronephrotic rat kidney. During norepinephrine-induced constriction, the addition of aranidipine dilated both afferent and efferent arterioles in a dose-dependent manner; at 10(-6) M, 83 +/- 6% and 90 +/- 6% reversal, respectively. In contrast, its active metabolite exerted dilator action predominantly on the afferent arteriole (79 +/- 4% vs. 44 +/- 17% at 10(-6) M for afferent and efferent arterioles, respectively). We further examined the long-term (8 weeks) effect of these agents on the development of renal injury in salt-loaded subtotally nephrectomized spontaneously hypertensive rats. Both aranidipine and M-1 reduced blood pressure by a similar magnitude. The decreases in proteinuria were observed in the aranidipine-treated group at weeks 6, 8, and 10, whereas in the M-1 group, significant reduction was attained only at week 6. Histopathologic examination revealed that both treatments improved glomerular and arteriolar sclerosis. Glomerular sclerosis, however, was less pronounced in the aranidipine-treated group than in the M-1 group. In conclusion, aranidipine has dilator action on both arterioles, whereas M-1 caused predominant dilation of afferent arterioles. Such metabolic changes may constitute a determinant of efferent arteriolar action of the calcium antagonist.

A depth-averaged debris-flow model that includes the effects of evolving dilatancy. I. physical basis

USGS Publications Warehouse

Iverson, Richard M.; George, David L.

2014-01-01

To simulate debris-flow behaviour from initiation to deposition, we derive a depth-averaged, two-phase model that combines concepts of critical-state soil mechanics, grain-flow mechanics and fluid mechanics. The model's balance equations describe coupled evolution of the solid volume fraction, m, basal pore-fluid pressure, flow thickness and two components of flow velocity. Basal friction is evaluated using a generalized Coulomb rule, and fluid motion is evaluated in a frame of reference that translates with the velocity of the granular phase, vs. Source terms in each of the depth-averaged balance equations account for the influence of the granular dilation rate, defined as the depth integral of ∇⋅vs. Calculation of the dilation rate involves the effects of an elastic compressibility and an inelastic dilatancy angle proportional to m−meq, where meq is the value of m in equilibrium with the ambient stress state and flow rate. Normalization of the model equations shows that predicted debris-flow behaviour depends principally on the initial value of m−meq and on the ratio of two fundamental timescales. One of these timescales governs downslope debris-flow motion, and the other governs pore-pressure relaxation that modifies Coulomb friction and regulates evolution of m. A companion paper presents a suite of model predictions and tests.

Cardiac myosin missense mutations cause dilated cardiomyopathy in mouse models and depress molecular motor function.

PubMed

Schmitt, Joachim P; Debold, Edward P; Ahmad, Ferhaan; Armstrong, Amy; Frederico, Andrea; Conner, David A; Mende, Ulrike; Lohse, Martin J; Warshaw, David; Seidman, Christine E; Seidman, J G

2006-09-26

Dilated cardiomyopathy (DCM) leads to heart failure, a leading cause of death in industrialized nations. Approximately 30% of DCM cases are genetic in origin, with some resulting from point mutations in cardiac myosin, the molecular motor of the heart. The effects of these mutations on myosin's molecular mechanics have not been determined. We have engineered two murine models characterizing the physiological, cellular, and molecular effects of DCM-causing missense mutations (S532P and F764L) in the alpha-cardiac myosin heavy chain and compared them with WT mice. Mutant mice developed morphological and functional characteristics of DCM consistent with the human phenotypes. Contractile function of isolated myocytes was depressed and preceded left ventricular dilation and reduced fractional shortening. In an in vitro motility assay, both mutant cardiac myosins exhibited a reduced ability to translocate actin (V(actin)) but had similar force-generating capacities. Actin-activated ATPase activities were also reduced. Single-molecule laser trap experiments revealed that the lower V(actin) in the S532P mutant was due to a reduced ability of the motor to generate a step displacement and an alteration of the kinetics of its chemomechanical cycle. These results suggest that the depressed molecular function in cardiac myosin may initiate the events that cause the heart to remodel and become pathologically dilated.

Comparative effects of torasemide and furosemide on gap junction proteins and cardiac fibrosis in a rat model of dilated cardiomyopathy.

PubMed

Watanabe, Kenichi; Sreedhar, Remya; Thandavarayan, Rajarajan A; Karuppagounder, Vengadeshprabhu; Giridharan, Vijayasree V; Antony, Shanish; Harima, Meilei; Nakamura, Masahiko; Suzuki, Kenji; Suzuki, Hiroshi; Sone, Hirohito; Arumugam, Somasundaram

2017-03-01

Cardiac fibrosis is the major hallmark of adverse cardiac remodeling in chronic heart failure (CHF) and its therapeutic targeting might help against cardiac dysfunction during chronic conditions. Diuretic agents are potentially useful in these cases, but their effects on the cardiac fibrosis pathogenesis are yet to be identified. This study was designed to identify and compare the effects of diuretic drugs torasemide and furosemide on cardiac fibrosis in a rat model of dilated cardiomyopathy induced by porcine cardiac myosin mediated experimental autoimmune myocarditis. Gap junction proteins, connexin-43 and N-cadherin, expressions were downregulated in the hearts of CHF rats, while torasemide treatment has upregulated their expression. Western blotting and immunohistochemical analysis for various cardiac fibrosis related proteins as well as histopathological studies have shown that both drugs have potential anti-fibrotic effects. Among them, torasemide has superior efficacy in offering protection against adverse cardiac remodeling in the selected rat model of dilated cardiomyopathy. In conclusion, torasemide treatment has potential anti-fibrotic effect in the hearts of CHF rats, possibly via improving the gap junction proteins expression and thereby improving the cell-cell interaction in the heart. © 2016 BioFactors, 43(2):187-194, 2017. © 2016 International Union of Biochemistry and Molecular Biology.

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

Does self-administered vaginal misoprostol result in cervical ripening in postmenopausal women after 14 days of pre-treatment with estradiol? Trial protocol for a randomised, placebo-controlled sequential trial.

PubMed

Oppegaard, K S; Lieng, M; Berg, A; Istre, O; Qvigstad, E; Nesheim, B-I

2008-06-01

To compare the impact of 1000 micrograms of self-administered vaginal misoprostol versus self-administered vaginal placebo on preoperative cervical ripening after pre-treatment with estradiol vaginal tablets at home in postmenopausal women prior to day-care operative hysteroscopy. Randomised double-blind placebo-controlled sequential trial. The boundaries for the sequential trial were calculated on the primary outcomes of a difference of cervical dilatation > or = 1 millimetre, with the assumption of a type 1 error of 0.05 and a power of 0.95. Norwegian university teaching hospital. Postmenopausal women referred for day-care operative hysteroscopy. The women were randomised to either 1000 micrograms of self-administered vaginal misoprostol or self-administered vaginal placebo the evening before day-care operative hysteroscopy. All women had administered a 25-microgram vaginal estradiol tablet daily for 14 days prior to the operation. Preoperative cervical dilatation (difference between misoprostol and placebo group, primary outcome), difference in dilatation before and after administration of misoprostol or placebo, number of women who achieve a preoperative cervical dilatation > or = 5 millimetres, acceptability, complications and side effects (secondary outcomes). Intra-operative findings and distribution of cervical dilatation in the two treatment groups: values are given as median (range) or n (%). Difference in dilatation before and after administration of misoprostol and placebo: values are given as median (range) of intraindividual differences. Percentage of women who achieve a cervical dilatation of > or = 5 mm, percentage of women who were difficult to dilate. Acceptability in the two treatment groups: values are given as completely acceptable n (%), fairly acceptable n (%), fairly unacceptable n (%), completely unacceptable n (%). Pain in the two treatment groups: pain was measured with a visual analogue scale ranging from 0 (no pain) to 10 (unbearable pain): values are given as median (range). Occurrence of side effects in the two treatment groups. Values are given as n (%). Complications given as n (%). No pharmaceutical company was involved in this study. A research grant from the regional research board of Northern Norway has been awarded to finance Dr K.S.O.'s leave from Hammerfest hospital as well as travel expenses between Hammerfest and Oslo, and research courses. The research grant from Prof B.I.N. (Helse Øst) funded the purchase of estradiol tablets, the manufacturing costs of misoprostol and placebo capsules from the hospital pharmacy, as well as the costs incurred for preparing the randomisation schedule and distribution of containers containing capsules to hospital. Prof B.I.N.'s research grant also funded insurance for the study participants. Estimated completion date 31 December 2008.

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.

Depressed perivascular sensory innervation of mouse mesenteric arteries with advanced age.

PubMed

Boerman, Erika M; Segal, Steven S

2016-04-15

The dilatory role for sensory innervation of mesenteric arteries (MAs) is impaired in Old (∼24 months) versus Young (∼4 months) mice. We investigated the nature of this impairment in isolated pressurized MAs. With perivascular sensory nerve stimulation, dilatation and inhibition of sympathetic vasoconstriction observed in Young MAs were lost in Old MAs along with impaired dilatation to calcitonin gene-related peptide (CGRP). Inhibiting NO and prostaglandin synthesis increased CGRP EC50 in Young and Old MAs. Endothelial denudation attenuated dilatation to CGRP in Old MAs yet enhanced dilatation to CGRP in Young MAs while abolishing all dilatations to ACh. In Old MAs, sensory nerve density was reduced and RAMP1 (CGRP receptor component) associated with nuclear regions of endothelial cells in a manner not seen in Young MAs or in smooth muscle cells of either age. With advanced age, loss of dilatory signalling mediated through perivascular sensory nerves may compromise perfusion of visceral organs. Vascular dysfunction and sympathetic nerve activity increase with advancing age. In the gut, blood flow is governed by perivascular sensory and sympathetic nerves but little is known of how their functional role is affected by advanced age. We tested the hypothesis that functional sensory innervation of mesenteric arteries (MAs) is impaired for Old (24 months) versus Young (4 months) C57BL/6 male mice. In cannulated pressurized MAs preconstricted 50% with noradrenaline and treated with guanethidine (to inhibit sympathetic neurotransmission), perivascular nerve stimulation (PNS) evoked dilatation in Young but not Old MAs while dilatations to ACh were not different between age groups. In Young MAs, capsaicin (to inhibit sensory neurotransmission) blocked dilatation and increased constriction during PNS. With no difference in efficacy, the EC50 of CGRP as a vasodilator was ∼6-fold greater in Old versus Young MAs. Inhibiting nitric oxide (l-NAME) and prostaglandin (indomethacin) synthesis increased CGRP EC50 in both age groups. Endothelial denudation reduced the efficacy of dilatation to CGRP by ∼30% in Old MAs yet increased this efficacy ∼15% in Young MAs while all dilatations to ACh were abolished. Immunolabelling revealed reduced density of sensory (CGRP) but not sympathetic (tyrosine hydroxylase) innervation for Old versus Young MAs. Whereas the distribution of CGRP receptor proteins was similar in SMCs, RAMP1 associated with nuclear regions of endothelial cells of Old but not Young MAs. With advanced age, the loss of sensory nerve function and diminished effectiveness of CGRP as a vasodilator is multifaceted and may adversely affect splanchnic perfusion. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

Disentangling reward anticipation with simultaneous pupillometry / fMRI.

PubMed

Schneider, Max; Leuchs, Laura; Czisch, Michael; Sämann, Philipp G; Spoormaker, Victor I

2018-05-05

The reward system may provide an interesting intermediate phenotype for anhedonia in affective disorders. Reward anticipation is characterized by an increase in arousal, and previous studies have linked the anterior cingulate cortex (ACC) to arousal responses such as dilation of the pupil. Here, we examined pupil dynamics during a reward anticipation task in forty-six healthy human subjects and evaluated its neural correlates using functional magnetic resonance imaging (fMRI). Pupil size showed a strong increase during monetary reward anticipation, a moderate increase during verbal reward anticipation and a decrease during control trials. For fMRI analyses, average pupil size and pupil change were computed in 1-s time bins during the anticipation phase. Activity in the ventral striatum was inversely related to the pupil size time course, indicating an early onset of activation and a role in reward prediction processing. Pupil dilations were linked to increased activity in the salience network (dorsal ACC and bilateral insula), which likely triggers an increase in arousal to enhance task performance. Finally, increased pupil size preceding the required motor response was associated with activity in the ventral attention network. In sum, pupillometry provides an effective tool for disentangling different phases of reward anticipation, with relevance for affective symptomatology. Copyright © 2018 Elsevier Inc. All rights reserved.

Evaluation of second-generation sequencing of 19 dilated cardiomyopathy genes for clinical applications.

PubMed

Gowrisankar, Sivakumar; Lerner-Ellis, Jordan P; Cox, Stephanie; White, Emily T; Manion, Megan; LeVan, Kevin; Liu, Jonathan; Farwell, Lisa M; Iartchouk, Oleg; Rehm, Heidi L; Funke, Birgit H

2010-11-01

Medical sequencing for diseases with locus and allelic heterogeneities has been limited by the high cost and low throughput of traditional sequencing technologies. "Second-generation" sequencing (SGS) technologies allow the parallel processing of a large number of genes and, therefore, offer great promise for medical sequencing; however, their use in clinical laboratories is still in its infancy. Our laboratory offers clinical resequencing for dilated cardiomyopathy (DCM) using an array-based platform that interrogates 19 of more than 30 genes known to cause DCM. We explored both the feasibility and cost effectiveness of using PCR amplification followed by SGS technology for sequencing these 19 genes in a set of five samples enriched for known sequence alterations (109 unique substitutions and 27 insertions and deletions). While the analytical sensitivity for substitutions was comparable to that of the DCM array (98%), SGS technology performed better than the DCM array for insertions and deletions (90.6% versus 58%). Overall, SGS performed substantially better than did the current array-based testing platform; however, the operational cost and projected turnaround time do not meet our current standards. Therefore, efficient capture methods and/or sample pooling strategies that shorten the turnaround time and decrease reagent and labor costs are needed before implementing this platform into routine clinical applications.

Comparison of the recurrence rate of gastric dilatation with or without volvulus in dogs after circumcostal gastropexy versus gastrocolopexy.

PubMed

Eggertsdóttir, A V; Stigen y, Ø; Lønaas, L; Langeland, M; Devor, M; Vibe-Petersen, G; Eriksen, T

2001-01-01

To compare the recurrence rate of acute gastric dilatation with or without volvulus (GDV) after circumcostal gastropexy (CCGP) or gastrocolopexy (GCP) in dogs. A prospective, double-blind, multicenter, randomized, controlled, clinical trial with two groups (A and B). Fifty-four client-owned dogs presented for treatment of GDV. Dogs with acute GDV that had not previously had a gastropexy performed were included. The preoperative treatment before gastropexy was standardized. A CCGP was performed on dogs in group A, and a GCP was performed on dogs in group B. Postoperative treatment was standardized, but deviation did occur according to the special needs of particular patients. A minimal follow-up time of 180 days was required for dogs not excluded from the study. The median follow-up time in group A was 700 days; in group B, it was 400 days. The occurrence of abdominal pain and gastrointestinal problems after surgery were recorded by the owners. There was no significant difference in the recurrence rate of GDV between the two groups. At the end of the study, the recurrence rate was 9% and 20% in group A and in group B, respectively. Both surgical techniques are effective in preventing recurrence of GDV. Copyright 2001 by The American College of Veterinary Surgeons

Cohesion, Cracking, Dilation, and Flow -- Rheological Behavior of Cohesive Pharmaceutical Powders

NASA Astrophysics Data System (ADS)

Muzzio, Fernando

2007-03-01

Cohesive powders can be loosely defined as systems where the attractive forced between particles exceed the average particle weight. Cohesive powder flow is interesting from a wide range of reasons. Their main characteristic, intermittence, is evidenced both in the interruption of flow out of hoppers (a mundane issue causing great annoyance to industrial practitioners) and in the sudden avalanching of snow and dirt that has terrified and terrified mankind since the dawn of time. At the present time, our ability to predict either of these phenomena (and many more involving cohesive powders) is very limited, primarily due to an incomplete understanding of their constitutive behavior. To wit, consider just a simple fact: a flowing powder never has constant density. Equations describing the relationship between velocity, shear, stress, and density are rudimentary at best. Computational and experimental approaches for characterizing flow behavior are in their infancy. In this talk, I will describe some recent progress achieved at Rutgers by our group. New instruments have been developed to determine simultaneously powder density and cohesive flow effects. Extensive measurements have been carried out focusing on pharmaceutical blends. These results have been used to fine-tune computational models that accurately predict dilation, flow in drums, and flow in hoppers. Impact of these observations for pharmaceutical manufacturing applications will be discussed in some detail.

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 ...

Recent Clinical Drug Trials Evidence in Marfan Syndrome and Clinical Implications.

PubMed

Singh, Michael N; Lacro, Ronald V

2016-01-01

Marfan syndrome is a genetic disorder of connective tissue with principal manifestations in the cardiovascular, ocular, and skeletal systems. Cardiovascular disease, mainly progressive aortic root dilation and aortic dissection, is the leading cause of morbidity and mortality. The primary aims of this report were to examine the evidence related to medical therapy for Marfan syndrome, including recently completed randomized clinical trials on the efficacy of β-blockers and angiotensin II receptor blockers for the prophylactic treatment of aortic enlargement in Marfan syndrome, and to provide recommendations for medical therapy on the basis of available evidence. Medical therapy for Marfan syndrome should be individualized according to patient tolerance and risk factors such as age, aortic size, and family history of aortic dissection. The Pediatric Heart Network trial showed that atenolol and losartan each reduced the rate of aortic dilation. All patients with known or suspected Marfan syndrome and aortic root dilation should receive medical therapy with adequate doses of either β-blocker or angiotensin receptor blocker. The Pediatric Heart Network trial also showed that atenolol and losartan are more effective at reduction of aortic root z score in younger subjects, which suggests that medical therapy should be prescribed even in the youngest children with aortic dilation. For patients with Marfan syndrome without aortic dilation, the available evidence is less clear. If aortic dilation is severe and/or progressive, therapy with a combination of β-blocker and angiotensin receptor blocker should be considered, although trial results are mixed with respect to the efficacy of combination therapy vs monotherapy. Copyright © 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

Endoscopic management of esophageal stenosis in children: New and traditional treatments.

PubMed

Dall'Oglio, Luigi; Caldaro, Tamara; Foschia, Francesca; Faraci, Simona; Federici di Abriola, Giovanni; Rea, Francesca; Romeo, Erminia; Torroni, Filippo; Angelino, Giulia; De Angelis, Paola

2016-02-25

Post-esophageal atresia anastomotic strictures and post-corrosive esophagitis are the most frequent types of cicatricial esophageal stricture. Congenital esophageal stenosis has been reported to be a rare but typical disease in children; other pediatric conditions are peptic, eosinophilic esophagitis and dystrophic recessive epidermolysis bullosa strictures. The conservative treatment of esophageal stenosis and strictures (ES) rather than surgery is a well-known strategy for children. Before planning esophageal dilation, the esophageal morphology should be assessed in detail for its length, aspect, number and level, and different conservative strategies should be chosen accordingly. Endoscopic dilators and techniques that involve different adjuvant treatment strategies have been reported and depend on the stricture's etiology, the availability of different tools and the operator's experience and preferences. Balloon and semirigid dilators are the most frequently used tools. No high-quality studies have reported on the differences in the efficacies and rates of complications associated with these two types of dilators. There is no consensus in the literature regarding the frequency of dilations or the diameter that should be achieved. The use of adjuvant treatments has been reported in cases of recalcitrant stenosis or strictures with evidence of dysphagic symptoms. Corticosteroids (either systemically or locally injected), the local application of mitomycin C, diathermy and laser ES sectioning have been reported. Some authors have suggested that stenting can reduce both the number of dilations and the treatment length. In many cases, this strategy is effective when either metallic or plastic stents are utilized. Treatment complications, such esophageal perforations, can be conservatively managed, considering surgery only in cases with severe pleural cavity involvement. In cases of stricture relapse, even if such relapses occur following the execution of well-conducted conservative strategies, surgical stricture resection and anastomosis or esophageal substitution are the only remaining options.

Contribution of Optical Zone Decentration and Pupil Dilation on the Change of Optical Quality After Myopic Photorefractive Keratectomy in a Cat Model

PubMed Central

Bühren, Jens; Yoon, Geunyoung; MacRae, Scott; Huxlin, Krystel

2010-01-01

PURPOSE To simulate the simultaneous contribution of optical zone decentration and pupil dilation on retinal image quality using wavefront error data from a myopic photorefractive keratectomy (PRK) cat model. METHODS Wavefront error differences were obtained from five cat eyes 19±7 weeks (range: 12 to 24 weeks) after spherical myopic PRK for −6.00 diopters (D) (three eyes) and −10.00 D (two eyes). A computer model was used to simulate decentration of a 6-mm sub-aperture relative to the measured wavefront error difference. Changes in image quality (visual Strehl ratio based on the optical transfer function [VSOTF]) were computed for simulated decentrations from 0 to 1500 μm over pupil diameters of 3.5 to 6.0 mm in 0.5-mm steps. For each eye, a bivariate regression model was applied to calculate the simultaneous contribution of pupil dilation and decentration on the pre- to postoperative change of the log VSOTF. RESULTS Pupil diameter and decentration explained up to 95% of the variance of VSOTF change (adjusted R2=0.95). Pupil diameter had a higher impact on VSOTF (median β=−0.88, P<.001) than decentration (median β= −0.45, P<.001). If decentration-induced lower order aberrations were corrected, the impact of decentration further decreased (β= −0.26) compared to the influence of pupil dilation (β= −0.95). CONCLUSIONS Both pupil dilation and decentration of the optical zone affected the change of retinal image quality (VSOTF) after myopic PRK with decentration exerting a lower impact on VSOTF change. Thus, under physiological conditions pupil dilation is likely to have more effect on VSOTF change after PRK than optical zone decentration. PMID:20229950

Contribution of optical zone decentration and pupil dilation on the change of optical quality after myopic photorefractive keratectomy in a cat model.

PubMed

Bühren, Jens; Yoon, Geunyoung; MacRae, Scott; Huxlin, Krystel

2010-03-01

To simulate the simultaneous contribution of optical zone decentration and pupil dilation on retinal image quality using wavefront error data from a myopic photorefractive keratectomy (PRK) cat model. Wavefront error differences were obtained from five cat eyes 19+/-7 weeks (range: 12 to 24 weeks) after spherical myopic PRK for -6.00 diopters (D) (three eyes) and -10.00 D (two eyes). A computer model was used to simulate decentration of a 6-mm sub-aperture relative to the measured wavefront error difference. Changes in image quality (visual Strehl ratio based on the optical transfer function [VSOTF]) were computed for simulated decentrations from 0 to 1500 mum over pupil diameters of 3.5 to 6.0 mm in 0.5-mm steps. For each eye, a bivariate regression model was applied to calculate the simultaneous contribution of pupil dilation and decentration on the pre- to postoperative change of the log VSOTF. Pupil diameter and decentration explained up to 95% of the variance of VSOTF change (adjusted R(2)=0.95). Pupil diameter had a higher impact on VSOTF (median beta=-0.88, P<.001) than decentration (median beta=-0.45, P<.001). If decentration-induced lower order aberrations were corrected, the impact of decentration further decreased (beta=-0.26) compared to the influence of pupil dilation (beta=-0.95). Both pupil dilation and decentration of the optical zone affected the change of retinal image quality (VSOTF) after myopic PRK with decentration exerting a lower impact on VSOTF change. Thus, under physiological conditions pupil dilation is likely to have more effect on VSOTF change after PRK than optical zone decentration. Copyright 2010, SLACK Incorporated.

Long-term effects of weight loss with a very-low carbohydrate, low saturated fat diet on flow mediated dilatation in patients with type 2 diabetes: A randomised controlled trial.

PubMed

Wycherley, Thomas P; Thompson, Campbell H; Buckley, Jonathan D; Luscombe-Marsh, Natalie D; Noakes, Manny; Wittert, Gary A; Brinkworth, Grant D

2016-09-01

Very-low carbohydrate diets can improve glycaemic control in patients with type 2 diabetes (T2DM). However, compared to traditional higher carbohydrate, low fat (HighCHO) diets, they have been associated with impaired endothelial function (measured by flow mediated dilatation [FMD]) that is possibly related to saturated fat. This study aimed to examine the effects of a 12-month hypocaloric very-low carbohydrate, low saturated fat (LowCHO) diet compared to an isocaloric HighCHO diet. One hundred and fifteen obese patients with T2DM (age:58.4 ± 0.7 [SEM] yr, BMI:34.6 ± 0.4 kg/m(2), HbA1c:7.33 [56.3 mmol/mol] ± 0.10%) were randomised to consume an energy restricted LowCHO diet (Carb:Pro:Fat:Sat-Fat 14:28:58: < 10% energy; n = 58) or isocaloric HighCHO diet (53:17:30: < 10%; n = 57) whilst undertaking exercise (60 min, 3/wk). Bodyweight, HbA1c and FMD were assessed. Seventy eight participants completed the intervention (LowCHO = 41, HighCHO = 37). Both groups experienced similar reductions in weight and HbA1c (-10.6 ± 0.7 kg, -1.05 ± 0.10%; p < 0.001 time, p ≥ 0.48 time × diet). FMD did not change (p = 0.11 time, p = 0.20 time × diet). In patients with obesity and T2DM, HighCHO diet and LowCHO diet have similar effects on endothelial function. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

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.

Effects of emergency cervical cerclage on pregnancy outcome: a retrospective study of 158 cases.

PubMed

Zhu, Li-Qiong; Chen, Hui; Chen, Li-Bin; Liu, Ying-Lin; Tian, Jian-Ping; Wang, Yun-Hui; Zhang, Rui; Zhang, Jian-Ping

2015-05-15

The aim of this study was to evaluate the effectiveness and safety of emergency cervical cerclage in women with advanced cervical dilatation and bulging of fetal membranes. The study included 158 women who underwent emergency cervical cerclage because of cervix dilatation and protruding membranes in mid-trimester at Sun Yat-sen Memorial Hospital of Sun Yat-sen University. Pregnancy outcomes and pregnancy outcome related to clinical features were analyzed retrospectively. Analysis revealed that the placement of emergency cerclage led to the delivery of live infants with a success rate of 82.28%. The mean interval between cerclage and delivery was 52.16.±26.62 days, with a mean gestation at delivery of 30.3±4.7 weeks and a mean birth weight of 1934.69±570.37 g. No severe maternal complications such as maternal death, hematosepsis, and hysterorrhexis occurred after the operation. Two women (1.25%) had laceration of the cervix, 1 woman (0.61%) suffered pulmonary edema, and 2 women (1.25%) developed deep vein thrombosis (DVT). There were significant correlations between the pregnancy outcome and risk factors, including any presenting symptoms, cervical dilatation, postoperative white blood cell count, and C-reactive protein (CRP) value. No significant difference was found in women with good vs. poor outcome in terms of maternal age and obstetric histories. Emergency cervical cerclage is effective in prolonging pregnancy and improving neonatal outcome in women with cervical incompetence. It should be considered a viable option for women with a dilated cervix in mid-trimester.

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.

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).

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

Compressible Turbulent Channel Flows: DNS Results and Modeling

NASA Technical Reports Server (NTRS)

Huang, P. G.; Coleman, G. N.; Bradshaw, P.; Rai, Man Mohan (Technical Monitor)

1994-01-01

The present paper addresses some topical issues in modeling compressible turbulent shear flows. The work is based on direct numerical simulation of two supersonic fully developed channel flows between very cold isothermal walls. Detailed decomposition and analysis of terms appearing in the momentum and energy equations are presented. The simulation results are used to provide insights into differences between conventional time-and Favre-averaging of the mean-flow and turbulent quantities. Study of the turbulence energy budget for the two cases shows that the compressibility effects due to turbulent density and pressure fluctuations are insignificant. In particular, the dilatational dissipation and the mean product of the pressure and dilatation fluctuations are very small, contrary to the results of simulations for sheared homogeneous compressible turbulence and to recent proposals for models for general compressible turbulent flows. This provides a possible explanation of why the Van Driest density-weighted transformation is so successful in correlating compressible boundary layer data. Finally, it is found that the DNS data do not support the strong Reynolds analogy. A more general representation of the analogy is analysed and shown to match the DNS data very well.

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

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.

Entanglement of quantum clocks through gravity

NASA Astrophysics Data System (ADS)

Castro Ruiz, Esteban; Giacomini, Flaminia; Brukner, Časlav

2017-03-01

In general relativity, the picture of space-time assigns an ideal clock to each world line. Being ideal, gravitational effects due to these clocks are ignored and the flow of time according to one clock is not affected by the presence of clocks along nearby world lines. However, if time is defined operationally, as a pointer position of a physical clock that obeys the principles of general relativity and quantum mechanics, such a picture is, at most, a convenient fiction. Specifically, we show that the general relativistic mass-energy equivalence implies gravitational interaction between the clocks, whereas the quantum mechanical superposition of energy eigenstates leads to a nonfixed metric background. Based only on the assumption that both principles hold in this situation, we show that the clocks necessarily get entangled through time dilation effect, which eventually leads to a loss of coherence of a single clock. Hence, the time as measured by a single clock is not well defined. However, the general relativistic notion of time is recovered in the classical limit of clocks.

Entanglement of quantum clocks through gravity.

PubMed

Castro Ruiz, Esteban; Giacomini, Flaminia; Brukner, Časlav

2017-03-21

In general relativity, the picture of space-time assigns an ideal clock to each world line. Being ideal, gravitational effects due to these clocks are ignored and the flow of time according to one clock is not affected by the presence of clocks along nearby world lines. However, if time is defined operationally, as a pointer position of a physical clock that obeys the principles of general relativity and quantum mechanics, such a picture is, at most, a convenient fiction. Specifically, we show that the general relativistic mass-energy equivalence implies gravitational interaction between the clocks, whereas the quantum mechanical superposition of energy eigenstates leads to a nonfixed metric background. Based only on the assumption that both principles hold in this situation, we show that the clocks necessarily get entangled through time dilation effect, which eventually leads to a loss of coherence of a single clock. Hence, the time as measured by a single clock is not well defined. However, the general relativistic notion of time is recovered in the classical limit of clocks.

Entanglement of quantum clocks through gravity

PubMed Central

Castro Ruiz, Esteban; Giacomini, Flaminia; Brukner, Časlav

2017-01-01

In general relativity, the picture of space–time assigns an ideal clock to each world line. Being ideal, gravitational effects due to these clocks are ignored and the flow of time according to one clock is not affected by the presence of clocks along nearby world lines. However, if time is defined operationally, as a pointer position of a physical clock that obeys the principles of general relativity and quantum mechanics, such a picture is, at most, a convenient fiction. Specifically, we show that the general relativistic mass–energy equivalence implies gravitational interaction between the clocks, whereas the quantum mechanical superposition of energy eigenstates leads to a nonfixed metric background. Based only on the assumption that both principles hold in this situation, we show that the clocks necessarily get entangled through time dilation effect, which eventually leads to a loss of coherence of a single clock. Hence, the time as measured by a single clock is not well defined. However, the general relativistic notion of time is recovered in the classical limit of clocks. PMID:28270623

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.

The cystic dilation of ventriculus terminalis with neurological symptoms: Three case reports and a literature review.

PubMed

Lotfinia, Iraj; Mahdkhah, Ata

2018-05-23

The ventriculus terminalis (VT) is a very small ependymal-lined residual lumen in the conus medullaris. It is normally present in all subjects during fetal development. VT in adults appears as an unusual pathology with an uncertain pathogenesis. In this paper, we described three case reports of symptomatic fifth ventricle cystic dilations. All of them were female and their mean age was 59 years. We treated them surgically and all three patients were improved based on clinical and imaging assessments. Our cases suggested that surgical decompression was a safe and effective treatment in symptomatic patients and the neurosurgeons should be aware of such rare situations. A complete list of differential diagnosis about other cystic dilations of the conus medullaris should be emphasized to select the correct clinical approach.

Pupil dilation reflects perceptual selection and predicts subsequent stability in perceptual rivalry

PubMed Central

Einhäuser, Wolfgang; Stout, James; Koch, Christof; Carter, Olivia

2008-01-01

During sustained viewing of an ambiguous stimulus, an individual's perceptual experience will generally switch between the different possible alternatives rather than stay fixed on one interpretation (perceptual rivalry). Here, we measured pupil diameter while subjects viewed different ambiguous visual and auditory stimuli. For all stimuli tested, pupil diameter increased just before the reported perceptual switch and the relative amount of dilation before this switch was a significant predictor of the subsequent duration of perceptual stability. These results could not be explained by blink or eye-movement effects, the motor response or stimulus driven changes in retinal input. Because pupil dilation reflects levels of norepinephrine (NE) released from the locus coeruleus (LC), we interpret these results as suggestive that the LC–NE complex may play the same role in perceptual selection as in behavioral decision making. PMID:18250340

Jejuno-jejunal intussusception in a guinea pig (Cavia porcellus)

PubMed Central

Fetzer, Tara J.; Mans, Christoph

2017-01-01

An approximately four-year-old male castrated guinea pig (Cavia porcellus) was presented for painful defecation with a 24-hour history of hyporexia and intermittent episodes of rolling behavior. Upon presentation the patient was quiet, alert, and responsive, and mildly hypothermic. Abdominal palpation revealed an approximately 2-cm long oblong mass within the caudal abdomen. Abdominal radiographs revealed gastric dilation without volvulus and a peritoneal mass effect. The patient was euthanized following gastric reflux of brown malodorous fluid from his nares and oral cavity. A necropsy was performed and revealed a jejuno-jejunal intussusception causing mechanical gastrointestinal ileus, and gastric dilatation without volvulus. While non-obstructive gastrointestinal stasis is common and obstructive ileus is uncommon in guinea pigs, this report shows that intestinal intussusception is a differential in guinea pigs with ileus and gastric dilatation. PMID:29038782

Reversible dilatancy in entangled single-wire materials.

PubMed

Rodney, David; Gadot, Benjamin; Martinez, Oriol Riu; du Roscoat, Sabine Rolland; Orgéas, Laurent

2016-01-01

Designing structures that dilate rapidly in both tension and compression would benefit devices such as smart filters, actuators or fasteners. This property however requires an unusual Poisson ratio, or Poisson function at finite strains, which has to vary with applied strain and exceed the familiar bounds: less than 0 in tension and above 1/2 in compression. Here, by combining mechanical tests and discrete element simulations, we show that a simple three-dimensional architected material, made of a self-entangled single long coiled wire, behaves in between discrete and continuum media, with a large and reversible dilatancy in both tension and compression. This unusual behaviour arises from an interplay between the elongation of the coiled wire and rearrangements due to steric effects, which, unlike in traditional discrete media, are hysteretically reversible when the architecture is made of an elastic fibre.

Effect of Phenylephrine on the Accommodative System

PubMed Central

Del Águila-Carrasco, Antonio J.; Bernal-Molina, Paula; Ferrer-Blasco, Teresa; López-Gil, Norberto; Montés-Micó, Robert

2016-01-01

Accommodation is controlled by the action of the ciliary muscle and mediated primarily by parasympathetic input through postganglionic fibers that originate from neurons in the ciliary and pterygopalatine ganglia. During accommodation the pupil constricts to increase the depth of focus of the eye and improve retinal image quality. Researchers have traditionally faced the challenge of measuring the accommodative properties of the eye through a small pupil and thus have relied on pharmacological agents to dilate the pupil. Achieving pupil dilation (mydriasis) without affecting the accommodative ability of the eye (cycloplegia) could be useful in many clinical and research contexts. Phenylephrine hydrochloride (PHCl) is a sympathomimetic agent that is used clinically to dilate the pupil. Nevertheless, first investigations suggested some loss of functional accommodation in the human eye after PHCl instillation. Subsequent studies, based on different measurement procedures, obtained contradictory conclusions, causing therefore an unexpected controversy that has been spread almost to the present days. This manuscript reviews and summarizes the main research studies that have been performed to analyze the effect of PHCl on the accommodative system and provides clear conclusions that could help clinicians know the real effects of PHCl on the accommodative system of the human eye. PMID:28053778

Morphological examination of the effects of defibrotide on experimentally induced bladder injury and its relation to interstitial cystitis.

PubMed

Aydin, H; Ercan, F; Cetinel, S; San, T

2001-08-01

This morphological study aims to investigate the effects of defibrotide, a deoxyribonucleic acid derivative drug with cytoprotective, immunosuppressive and vasorelaxant effects, on protamine sulfate induced bladder injury. Wistar albino female rats were catheterized and intravesically infused with phosphate buffered solution (control group) or, either protamine sulfate (bladder injury group) or protamine sulfate+defibrotide (bladder injury+defibrotide group) dissolved in phosphate buffered solution. The morphology of the urinary bladder was investigated using light and electron microscopy. The number of mast cells in the mucosa, mucosal alterations, intercellular junctions, surface topography and the glycosaminoglycan (GAG) layer as well as microvillus formation on the luminal surface were evaluated. In the bladder injury group, ulcerated areas, irregularity of the GAG layer, increased number of mast cells, vacuole formation, dilated perinuclear cistern, formation of pleomorphic and uniform microvilli and dilatations in the intercellular spaces in the urothelium were observed. In the bladder injury+defibrotide group a relatively normal urothelial topography, GAG layer and a few mast cells in the mucosa, some dilatations between the intercellular areas, less uniform microvilli, regular perinuclear cistern and tight junctions were observed. These results show that defibrotide can inhibit PS induced bladder damage.

Tea-induced improvement of endothelial function in humans: No role for epigallocatechin gallate (EGCG).

PubMed

Lorenz, Mario; Rauhut, Franziska; Hofer, Christine; Gwosc, Stefanie; Müller, Eda; Praeger, Damaris; Zimmermann, Benno F; Wernecke, Klaus-Dieter; Baumann, Gert; Stangl, Karl; Stangl, Verena

2017-05-23

Consumption of tea is inversely associated with cardiovascular diseases. However, the active compound(s) responsible for the protective effects of tea are unknown. Although many favorable cardiovascular effects in vitro are mediated by epigallocatechin gallate (EGCG), its contribution to the beneficial effects of tea in vivo remains unresolved. In a randomised crossover study, a single dose of 200 mg EGCG was applied in three different formulas (as green tea beverage, green tea extract (GTE), and isolated EGCG) to 50 healthy men. Flow-mediated dilation (FMD) and endothelial-independent nitro-mediated dilation (NMD) was measured before and two hours after ingestion. Plasma levels of tea compounds were determined after each intervention and correlated with FMD. FMD significantly improved after consumption of green tea containing 200 mg EGCG (p < 0.01). However, GTE and EGCG had no significant effect on FMD. NMD did not significantly differ between interventions. EGCG plasma levels were highest after administration of EGCG and lowest after consumption of green tea. Plasma levels of caffeine increased after green tea consumption. The results show that EGCG is most likely not involved in improvement of flow-mediated dilation by green tea. Instead, other tea compounds, metabolites or combinations thereof may play a role.

Management of complex glottic stenosis in children with recurrent respiratory papillomatosis.

PubMed

Siegel, Bianca; Smith, Lee P

2013-10-01

To describe our management of complex glottic stenosis in tracheotomy dependent children with severe recurrent respiratory papillomatosis. Retrospective chart review at a tertiary care children's hospital. Three children with complex glottic stenosis secondary to severe recurrent respiratory papillomatosis were treated at our institution since 2011. Two patients had complete stenosis, and the third had near-complete stenosis. Two patients were managed using balloon dilation alone, and the third also underwent laryngotracheal reconstruction with posterior costal cartilage grafting. Two patients have been successfully decannulated and the third has been tolerating continuous tracheotomy capping for greater than twelve months. All three patients underwent aggressive debridement of papillomatosis and balloon dilation every 4-6 weeks until their burden of disease was controlled. In two patients, the glottic airway was patent, and the third continued to have complete restenosis between procedures and required laryngotracheoplasty with multiple post-operative dilation procedures to establish an adequate glottic airway. Severe laryngeal stenosis is a well-described complication of recurrent respiratory papillomatosis, but its management is not well-defined. Aggressive management of papillomatosis with frequent debridement is critical in successfully managing laryngeal stenosis. Balloon dilation alone may be surprisingly effective in these patients, and laryngotracheoplasty can be used as an adjunct procedure in those patients who fail balloon dilation. Given the quality of life issues and concerns regarding distal spread of disease with tracheotomies in these patients, we feel that aggressive management and early decannulation is in the patient's best interest. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Dilatant shear band formation and diagenesis in calcareous, arkosic sandstones, Vienna Basin (Austria)

PubMed Central

Lommatzsch, Marco; Exner, Ulrike; Gier, Susanne; Grasemann, Bernhard

2015-01-01

The present study examines deformation bands in calcareous arkosic sands. The investigated units can be considered as an equivalent to the Matzen field in the Vienna Basin (Austria), which is one of the most productive oil reservoirs in central Europe. The outcrop exposes carbonate-free and carbonatic sediments of Badenian age separated by a normal fault. Carbonatic sediments in the hanging wall of the normal fault develop dilation bands with minor shear displacements (< 2 mm), whereas carbonate-free sediments in the footwall develop cataclastic shear bands with up to 70 cm displacement. The cataclastic shear bands show a permeability reduction up to 3 orders of magnitude and strong baffling effects in the vadose zone. Carbonatic dilation bands show a permeability reduction of 1-2 orders of magnitude and no baffling structures. We distinguished two types of deformation bands in the carbonatic units, which differ in deformation mechanisms, distribution and composition. Full-cemented bands form as dilation bands with an intense syn-kinematic calcite cementation, whereas the younger loose-cemented bands are dilatant shear bands cemented by patchy calcite and clay minerals. All analyzed bands are characterized by a porosity and permeability reduction caused by grain fracturing and cementation. The changed petrophysical properties and especially the porosity evolution are closely related to diagenetic processes driven by varying pore fluids in different diagenetic environments. The deformation band evolution and sealing capacity is controlled by the initial host rock composition. PMID:26300577

Self-similar assemblies of globular whey proteins at the air-water interface: effect of the structure.

PubMed

Mahmoudi, Najet; Gaillard, Cédric; Boué, François; Axelos, Monique A V; Riaublanc, Alain

2010-05-01

We investigated the structure of heat-induced assemblies of whey globular proteins using small angle neutron scattering (SANS), static and dynamic light scattering (SLS and DLS), and cryogenic transmission electron microscopy (Cryo-TEM). Whey protein molecules self-assemble in fractal aggregates with a structure density depending on the electrostatic interactions. We determined the static and dynamic properties of interfacial layer formed by the protein assemblies, upon adsorption and spreading at the air-water interface using surface film balance and interfacial dilatational rheology. Upon spreading, all whey protein systems show a power-law scaling behavior of the surface pressure versus concentration in the semi-dilute surface concentration regime, with an exponent ranging from 5.5 to 9 depending on the electrostatic interactions and the aggregation state. The dilatational modulus derived from surface pressure isotherms shows a main peak at 6-8 mN/m, generally considered to be the onset of a conformational change in the monolayer, and a second peak or a shoulder at 15 mN/m. Long-time adsorption kinetics give similar results for both the native whey proteins and the corresponding self-similar assemblies, with a systematic effect of the ionic strength. Copyright 2010 Elsevier Inc. All rights reserved.

The Immersive Virtual Reality Lab: Possibilities for Remote Experimental Manipulations of Autonomic Activity on a Large Scale.

PubMed

Juvrud, Joshua; Gredebäck, Gustaf; Åhs, Fredrik; Lerin, Nils; Nyström, Pär; Kastrati, Granit; Rosén, Jörgen

2018-01-01

There is a need for large-scale remote data collection in a controlled environment, and the in-home availability of virtual reality (VR) and the commercial availability of eye tracking for VR present unique and exciting opportunities for researchers. We propose and provide a proof-of-concept assessment of a robust system for large-scale in-home testing using consumer products that combines psychophysiological measures and VR, here referred to as a Virtual Lab. For the first time, this method is validated by correlating autonomic responses, skin conductance response (SCR), and pupillary dilation, in response to a spider, a beetle, and a ball using commercially available VR. Participants demonstrated greater SCR and pupillary responses to the spider, and the effect was dependent on the proximity of the stimuli to the participant, with a stronger response when the spider was close to the virtual self. We replicated these effects across two experiments and in separate physical room contexts to mimic variability in home environment. Together, these findings demonstrate the utility of pupil dilation as a marker of autonomic arousal and the feasibility to assess this in commercially available VR hardware and support a robust Virtual Lab tool for massive remote testing.

The Immersive Virtual Reality Lab: Possibilities for Remote Experimental Manipulations of Autonomic Activity on a Large Scale

PubMed Central

Juvrud, Joshua; Gredebäck, Gustaf; Åhs, Fredrik; Lerin, Nils; Nyström, Pär; Kastrati, Granit; Rosén, Jörgen

2018-01-01

There is a need for large-scale remote data collection in a controlled environment, and the in-home availability of virtual reality (VR) and the commercial availability of eye tracking for VR present unique and exciting opportunities for researchers. We propose and provide a proof-of-concept assessment of a robust system for large-scale in-home testing using consumer products that combines psychophysiological measures and VR, here referred to as a Virtual Lab. For the first time, this method is validated by correlating autonomic responses, skin conductance response (SCR), and pupillary dilation, in response to a spider, a beetle, and a ball using commercially available VR. Participants demonstrated greater SCR and pupillary responses to the spider, and the effect was dependent on the proximity of the stimuli to the participant, with a stronger response when the spider was close to the virtual self. We replicated these effects across two experiments and in separate physical room contexts to mimic variability in home environment. Together, these findings demonstrate the utility of pupil dilation as a marker of autonomic arousal and the feasibility to assess this in commercially available VR hardware and support a robust Virtual Lab tool for massive remote testing. PMID:29867318

Percutaneous dilatational versus conventional surgical tracheostomy in intensive care patients

PubMed Central

Youssef, Tarek F.; Ahmed, Mohamed Rifaat; Saber, Aly

2011-01-01

Background: Tracheostomy is usually performed in patients with difficult weaning from mechanical ventilation or some catastrophic neurologic insult. Conventional tracheostomy involves dissection of the pretracheal tissues and insertion of the tracheostomy tube into the trachea under direct vision. Percutaneous dilatational tracheostomy is increasingly popular and has gained widespread acceptance in many intensive care unit and trauma centers. Aim: Aim of the study was to compare percutaneous dilatational tracheostomy versus conventional tracheostomy in intensive care patients. Patients and Methods: 64 critically ill patients admitted to intensive care unit subjected to tracheostomy and randomly divided into two groups; percutaneous dilatational tracheostomy and conventional tracheostomy. Results: Mean duration of the procedure was similar between the two procedures while the mean size of tracheostomy tube was smaller in percutaneous technique. In addition, the Lowest SpO2 during procedure, PaCO2 after operation and intra-operative bleeding for both groups were nearly similar without any statistically difference. Postoperative infection after 7 days seen to be statistically lowered and the length of scar tend to be smaller among PDT patients. Conclusion: PDT technique is effective and safe as CST with low incidence of post operative complication. PMID:22361497

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

Role of endoscopic retrograde cholangiopancreatography in the management of benign biliary strictures: What’s new?

PubMed Central

Ferreira, Rosa; Loureiro, Rui; Nunes, Nuno; Santos, António Alberto; Maio, Rui; Cravo, Marília; Duarte, Maria Antónia

2016-01-01

Benign biliary strictures comprise a heterogeneous group of diseases. The most common strictures amenable to endoscopic treatment are post-cholecystectomy, post-liver transplantation, related to primary sclerosing cholangitis and to chronic pancreatitis. Endoscopic treatment of benign biliary strictures is widely used as first line therapy, since it is effective, safe, noninvasive and repeatable. Endoscopic techniques currently used are dilation, multiple plastic stents insertion and fully covered self-expandable metal stents. The main indication for dilation alone is primary sclerosing cholangitis related strictures. In the vast majority of the remaining cases, temporary placement of multiple plastic stents with/without dilation is considered the treatment of choice. Although this approach is effective, it requires multiple endoscopic sessions due to the short duration of stent patency. Fully covered self-expandable metal stents appear as a good alternative to plastic stents, since they have an increased radial diameter, longer stent patency, easier insertion technique and similar efficacy. Recent advances in endoscopic technique and various devices have allowed successful treatment in most cases. The development of novel endoscopic techniques and devices is still ongoing. PMID:26962404

Determinants of Thyrotoxic Cardiomyopathy Recovery

PubMed Central

Oliveros-Ruiz, Lucia; Vallejo, Maite; Diez Canseco, L. Fernando; Cárdenas, Manuel; Hermosillo, J. Antonio G.

2013-01-01

The purpose was to evaluate the effect of the disease duration prior to treatment, thyroid hormones level, or both on the reversibility of dilated cardiomyopathy. Between January 2006 and December 2010, a longitudinal study with a 6 months follow-up was carried on. One hundred and seventy patients with hyperthyroidism were referred to the cardiologist, and 127 had a 6 months followup after antithyroid treatment and were evaluated by echocardiography. Dilated cardiomyopathy reversibility criteria were established according to echocardiographic parameters. Complete reversibility existed when all parameters were met, partial reversibility when LVEF was ≥55% plus two or three other parameters, and no reversibility when LVEF was ≤55% regardless of other parameters. The results showed that echocardiography parameters related to the regression of myocardial mass were associated with a disease duration shorter than 10.38 months. This was the main predictive variable for reversal of dilated cardiomyopathy, followed by β-blocker treatment, and the last predictive variable was the serum level of free triiodothyronine. This study showed that the effect on the myocardium related to thyrotoxicosis was associated with the disease duration before treatment. PMID:24106705

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.

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.

High Dietary Sodium Intake Impairs Endothelium-Dependent Dilation in Healthy Salt-Resistant Humans

PubMed Central

DuPont, Jennifer J.; Greaney, Jody L.; Wenner, Megan M.; Lennon-Edwards, Shannon L.; Sanders, Paul W.; Farquhar, William B.; Edwards, David G.

2014-01-01

Excess dietary sodium has been linked to the development of hypertension and other cardiovascular diseases. In humans, the effects of sodium consumption on endothelial function have not been separated from the effects on blood pressure. The present study was designed to determine if dietary sodium intake affected endothelium-dependent dilation (EDD) independently of changes in blood pressure. Fourteen healthy salt resistant adults were studied (9M, 5F; age 33 ± 2.4 years) in a controlled feeding study. After a baseline run-in diet, participants were randomized to a 7 day high sodium (HS) (300-350 mmol/day) and 7 day low sodium (LS) (20 mmol/day) diet. Salt resistance, defined as a ≤ 5 mm Hg change in a 24-hour mean arterial pressure, was individually assessed while on the low sodium and high sodium diets and confirmed in the subjects undergoing study (LS: 85±1 mm Hg; HS: 85±2 mmHg). EDD was determined in each subject via brachial artery flow-mediated dilation on the last day of each diet. Sodium excretion increased during the high sodium diet (p < 0.01). EDD was reduced on the high sodium diet (Low: 10.3±0.9%, High: 7.3±0.7%, p < 0.05). The HS diet significantly suppressed plasma renin activity (PRA), plasma angiotensin II, and aldosterone (p < 0.05). These data demonstrate that excess salt intake in humans impairs endothelium-dependent dilation independently of changes in blood pressure. PMID:23263240

Flow mediated dilation of the brachial artery: an investigation of methods requiring further standardization

PubMed Central

Peretz, Alon; Leotta, Daniel F; Sullivan, Jeffrey H; Trenga, Carol A; Sands, Fiona N; Aulet, Mary R; Paun, Marla; Gill, Edward A; Kaufman, Joel D

2007-01-01

Background In order to establish a consistent method for brachial artery reactivity assessment, we analyzed commonly used approaches to the test and their effects on the magnitude and time-course of flow mediated dilation (FMD), and on test variability and repeatability. As a popular and noninvasive assessment of endothelial function, several different approaches have been employed to measure brachial artery reactivity with B-mode ultrasound. Despite some efforts, there remains a lack of defined normal values and large variability in measurement technique. Methods Twenty-six healthy volunteers underwent repeated brachial artery diameter measurements by B-mode ultrasound. Following baseline diameter recordings we assessed endothelium-dependent flow mediated dilation by inflating a blood pressure cuff either on the upper arm (proximal) or on the forearm (distal). Results Thirty-seven measures were performed using proximal occlusion and 25 with distal occlusion. Following proximal occlusion relative to distal occlusion, FMD was larger (16.2 ± 1.2% vs. 7.3 ± 0.9%, p < 0.0001) and elongated (107.2 s vs. 67.8 s, p = 0.0001). Measurement of the test repeatability showed that differences between the repeated measures were greater on average when the measurements were done using the proximal method as compared to the distal method (2.4%; 95% CI 0.5–4.3; p = 0.013). Conclusion These findings suggest that forearm compression holds statistical advantages over upper arm compression. Added to documented physiological and practical reasons, we propose that future studies should use forearm compression in the assessment of endothelial function. PMID:17376239

Acute retinal ischemia inhibits endothelium-dependent nitric oxide-mediated dilation of retinal arterioles via enhanced superoxide production.

PubMed

Hein, Travis W; Ren, Yi; Potts, Luke B; Yuan, Zhaoxu; Kuo, Enoch; Rosa, Robert H; Kuo, Lih

2012-01-03

Because retinal vascular disease is associated with ischemia and increased oxidative stress, the vasodilator function of retinal arterioles was examined after retinal ischemia induced by elevated intraocular pressure (IOP). The role of superoxide anions in the development of vascular dysfunction was assessed. IOP was increased and maintained at 80 to 90 mm Hg for 30, 60, or 90 minutes by infusing saline into the anterior chamber of a porcine eye. The fellow eye with normal IOP (10-20 mm Hg) served as control. In some pigs, superoxide dismutase mimetic TEMPOL (1 mM) or vehicle (saline) was injected intravitreally before IOP elevation. After enucleation, retinal arterioles were isolated and pressurized without flow for functional analysis by recording diameter changes using videomicroscopic techniques. Dihydroethidium (DHE) was used to detect superoxide production in isolated retinal arterioles. Isolated retinal arterioles developed stable basal tone and the vasodilations to endothelium-dependent nitric oxide (NO)-mediated agonists bradykinin and L-lactate were significantly reduced only by 90 minutes of ischemia. However, vasodilation to endothelium-independent NO donor sodium nitroprusside was unaffected after all time periods of ischemia. DHE staining showed that 90 minutes of ischemia significantly increased superoxide levels in retinal arterioles. Intravitreal injection of membrane-permeable radical scavenger but not vehicle before ischemia prevented elevation of vascular superoxide and preserved bradykinin-induced dilation. Endothelium-dependent NO-mediated dilation of retinal arterioles is impaired by 90 minutes of ischemia induced by elevated IOP. The inhibitory effect appears to be mediated by the alteration of NO signaling via vascular superoxide.

Targeting inflammatory pathways in myocardial infarction

PubMed Central

Christia, Panagiota; Frangogiannis, Nikolaos G

2013-01-01

Acute cardiomyocyte necrosis in the infarcted heart generates Damage-Associated Molecular Patterns (DAMPs), activating complement and Toll-Like Receptor (TLR)/Interleukin (IL)-1 signaling, and triggering an intense inflammatory reaction. Infiltrating leukocytes clear the infarct from dead cells, while activating reparative pathways that lead to formation of a scar. As the infarct heals the ventricle remodels; the geometric, functional and molecular alterations associated with post-infarction remodeling are driven by the inflammatory cascade and are involved in the development of heart failure. Because unrestrained inflammation in the infarcted heart induces matrix degradation and cardiomyocyte apoptosis, timely suppression of the post-infarction inflammatory reaction may be crucial to protect the myocardium from dilative remodeling and progressive dysfunction. Inhibition and resolution of post-infarction inflammation involves mobilization of inhibitory mononuclear cell subsets and requires activation of endogenous STOP signals. Our manuscript discusses the basic cellular and molecular events involved in initiation, activation and resolution of the post-infarction inflammatory response, focusing on identification of therapeutic targets. The failure of anti-integrin approaches in patients with myocardial infarction and a growing body of experimental evidence suggest that inflammation may not increase ischemic cardiomyocyte death, but accentuates matrix degradation causing dilative remodeling. Given the pathophysiologic complexity of post-infarction remodeling, personalized biomarker-based approaches are needed to target patient subpopulations with dysregulated inflammatory and reparative responses. Inhibition of pro-inflammatory signals (such as IL-1 and Monocyte Chemoattractant Protein-1) may be effective in patients with defective resolution of post-infarction inflammation who exhibit progressive dilative remodeling. In contrast, patients with predominant hypertrophic/fibrotic responses may benefit from anti-TGF strategies. PMID:23772948

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.

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.

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.

Is endoscopic papillary large balloon dilation safe for treating large CBD stones?

PubMed

Shim, Chan Sup; Kim, Ji Wan; Lee, Tae Yoon; Cheon, Young Koog

2016-01-01

In recent years, endoscopic papillary large balloon dilation (EPLBD) with endoscopic sphincterotomy (EST) has been shown to be an effective technique for the removal of large or difficult common bile duct (CBD) stones, as an alternative to EST. Reviewing the literature published since 2003, it is understood that EPLBD has fewer associated overall complications than EST. Bleeding occurred less frequently with EPLBD than with EST. There was no significant difference in postendoscopic retrograde cholangiopancreatography pancreatitis or perforation. Recent accumulated results of EPLBD with or even without EST suggest that it is a safe and effective procedure for the removal of large or difficult bile duct stones without any additional risk of severe adverse events, when performed under appropriate guidelines. Since use of a larger balloon can tear the sphincter as well as the bile duct, possibly resulting in bleeding and perforation, a balloon size that is equal to or smaller in diameter than the diameter of the native distal bile duct is recommended. The maximum transverse diameter of the stone and the balloon-stone diameter ratio have a tendency to affect the success or failure of complete removal of stones by large balloon dilation to prevent adverse effects such as perforation and bleeding. One should take into account the size of the native bile duct, the size and burden of stones, the presence of stricture of distal bile duct, and the presence of the papilla in or adjacent to a diverticulum. Even though the results of EPLBD indicate that it is a relatively safe procedure in patients with common duct stones with a dilated CBD, the recommended guidelines should be followed strictly for the prevention of major adverse events such as bleeding and perforation.

Percutaneous Injection of Lidocaine Within the Carotid Body Area in Carotid Artery Stenting: An 'Old-New' Technique

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

Mourikis, Dimitrios; Chatoupis, Konstantinos, E-mail: kchatoupis@yahoo.g; Katsenis, Konstantinos

2008-07-15

Severe bradycardia is a common untoward effect during balloon angioplasty when performing carotid artery stenting. Therefore atropine injection even before dilatation and the presence of an anesthesiologist are advocated in all patients. In the surgical literature, injection of a local anesthetic agent into the carotid sinus before carotid endarterectomy was performed in an attempt to ameliorate perioperative hemodynamic instability. This study was undertaken to test the hypothesis that percutaneous infiltration of the carotid sinus with local anesthetic immediately before balloon dilatation reduces bradycardia and ameliorates the need for atropine injection or the presence of an anesthesiologist. Infiltration of the carotidmore » sinus with 5 ml of 1% lidocaine, 3 min before dilatation, was performed in 30 consecutive patients. No one exhibited any significant rhythm change that required atropine injection. The anesthesiologist did not face any hemodynamic instability during the carotid artery stenting procedure.« less

Signatures of Mechanosensitive Gating.

PubMed

Morris, Richard G

2017-01-10

The question of how mechanically gated membrane channels open and close is notoriously difficult to address, especially if the protein structure is not available. This perspective highlights the relevance of micropipette-aspirated single-particle tracking-used to obtain a channel's diffusion coefficient, D, as a function of applied membrane tension, σ-as an indirect assay for determining functional behavior in mechanosensitive channels. While ensuring that the protein remains integral to the membrane, such methods can be used to identify not only the gating mechanism of a protein, but also associated physical moduli, such as torsional and dilational rigidity, which correspond to the protein's effective shape change. As an example, three distinct D-versus-σ "signatures" are calculated, corresponding to gating by dilation, gating by tilt, and gating by a combination of both dilation and tilt. Both advantages and disadvantages of the approach are discussed. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Congenital Nephrogenic Diabetes Insipidus Presented With Bilateral Hydronephrosis and Urinary Infection: A Case Report.

PubMed

Zheng, Kewen; Xie, Yi; Li, Hanzhong

2016-05-01

Nephrogenic diabetes insipidus (NDI) is a condition resulting from the kidney's impaired response to circulating antidiuretic hormone (ADH), leading to polydipsia and polyuria. Urinary tract dilatation caused by NDI is a rare situation. Here, we report a case of congenital NDI presented with bilateral hydronephrosis.A 15-year-old boy complaining a history of intermittent fever was admitted to Peking Union Medical College Hospital. He voided 10 to 15 L of urine daily. Radiographic examination revealed severe dilatation of bilateral renal pelvis, ureter, and bladder. Urinalysis shows hyposthenuria.He was diagnosed NDI since born. Transient insertion of a urethral catheter helped to relieve fever. Medical therapy of hydrochlorothiazide and amiloride was prescribed and effective.Dilatation of urinary tract caused by diabetes insipidus is rare, but may be present in severe condition. Therefore, it is crucial for clinicians to perform early treatment to avoid impairment of renal function.

Elements of an improved model of debris‐flow motion

USGS Publications Warehouse

Iverson, Richard M.

2009-01-01

A new depth‐averaged model of debris‐flow motion describes simultaneous evolution of flow velocity and depth, solid and fluid volume fractions, and pore‐fluid pressure. Non‐hydrostatic pore‐fluid pressure is produced by dilatancy, a state‐dependent property that links the depth‐averaged shear rate and volumetric strain rate of the granular phase. Pore‐pressure changes caused by shearing allow the model to exhibit rate‐dependent flow resistance, despite the fact that the basal shear traction involves only rate‐independent Coulomb friction. An analytical solution of simplified model equations shows that the onset of downslope motion can be accelerated or retarded by pore‐pressure change, contingent on whether dilatancy is positive or negative. A different analytical solution shows that such effects will likely be muted if downslope motion continues long enough, because dilatancy then evolves toward zero, and volume fractions and pore pressure concurrently evolve toward steady states.

Elements of an improved model of debris-flow motion

USGS Publications Warehouse

Iverson, R.M.

2009-01-01

A new depth-averaged model of debris-flow motion describes simultaneous evolution of flow velocity and depth, solid and fluid volume fractions, and pore-fluid pressure. Non-hydrostatic pore-fluid pressure is produced by dilatancy, a state-dependent property that links the depth-averaged shear rate and volumetric strain rate of the granular phase. Pore-pressure changes caused by shearing allow the model to exhibit rate-dependent flow resistance, despite the fact that the basal shear traction involves only rate-independent Coulomb friction. An analytical solution of simplified model equations shows that the onset of downslope motion can be accelerated or retarded by pore-pressure change, contingent on whether dilatancy is positive or negative. A different analytical solution shows that such effects will likely be muted if downslope motion continues long enough, because dilatancy then evolves toward zero, and volume fractions and pore pressure concurrently evolve toward steady states. ?? 2009 American Institute of Physics.

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.

Acute effect of mineralocorticoid receptor antagonism on vascular function in healthy older adults.

PubMed

Hwang, Moon-Hyon; Yoo, Jeung-Ki; Luttrell, Meredith; Kim, Han-Kyul; Meade, Thomas H; English, Mark; Talcott, Susanne; Jaffe, Iris Z; Christou, Demetra D

2016-01-01

Mineralocorticoid receptor (MR) activation by aldosterone may regulate vascular function in health or contribute to vascular dysfunction in cardiovascular disease. Whether the effects are beneficial or detrimental to vascular function appear to be dependent on the integrity of the vascular endothelium and whether the responses are short-term or chronic. Acute modulation of MR activation has resulted in conflicting outcomes on vascular function in young healthy adults. Little is known about the vascular role of aldosterone and MR activation in healthy human aging. The primary objective of this study was to examine whether acute inhibition of MR by the selective antagonist eplerenone, influences vascular function in healthy older adults. We performed a randomized, double-blind, placebo-controlled crossover study in 22 adults (61±1 years; mean±SE, 53-79 years) who were free from overt clinical cardiovascular disease. We measured brachial artery flow-mediated endothelium-dependent dilation and endothelium-independent dilation to sublingual nitroglycerin (0.4 mg) following eplerenone (100 mg/dose, 2 doses, 24h between doses) or placebo. In response to acute MR antagonism, flow-mediated dilation decreased by 19% (from 6.9±0.5 to 5.6±0.6%, P=0.02; placebo vs. eplerenone). Endothelial nitric oxide synthase (eNOS) activity also decreased following MR antagonism based on the ratio of phosphorylated eNOS(Ser1177) to total eNOS (1.53±0.08 vs. 1.29±0.06, P=0.02). Nitroglycerin-induced dilation and blood pressure were unaffected (nitroglycerin-induced dilation: 21.9±1.9 vs. 21.0±1.5%, P=0.5 and systolic/diastolic blood pressure: 135/77±4/2 vs. 134/77±4/2 mmHg, P≥0.6). In conclusion, acute MR antagonism impairs vascular endothelial function in healthy older adults without influencing vascular smooth muscle responsiveness to exogenous nitric oxide or blood pressure. Copyright © 2015 Elsevier Inc. All rights reserved.

Stenting for curved lesions using a novel curved balloon: Preliminary experimental study.

PubMed

Tomita, Hideshi; Higaki, Takashi; Kobayashi, Toshiki; Fujii, Takanari; Fujimoto, Kazuto

2015-08-01

Stenting may be a compelling approach to dilating curved lesions in congenital heart diseases. However, balloon-expandable stents, which are commonly used for congenital heart diseases, are usually deployed in a straight orientation. In this study, we evaluated the effect of stenting with a novel curved balloon considered to provide better conformability to the curved-angled lesion. In vitro experiments: A Palmaz Genesis(®) stent (Johnson & Johnson, Cordis Co, Bridgewater, NJ, USA) mounted on the Goku(®) curve (Tokai Medical Co. Nagoya, Japan) was dilated in vitro to observe directly the behavior of the stent and balloon assembly during expansion. Animal experiment: A short Express(®) Vascular SD (Boston Scientific Co, Marlborough, MA, USA) stent and a long Express(®) Vascular LD stent (Boston Scientific) mounted on the curved balloon were deployed in the curved vessel of a pig to observe the effect of stenting in vivo. In vitro experiments: Although the stent was dilated in a curved fashion, stent and balloon assembly also rotated conjointly during expansion of its curved portion. In the primary stenting of the short stent, the stent was dilated with rotation of the curved portion. The excised stent conformed to the curved vessel. As the long stent could not be negotiated across the mid-portion with the balloon in expansion when it started curving, the mid-portion of the stent failed to expand fully. Furthermore, the balloon, which became entangled with the stent strut, could not be retrieved even after complete deflation. This novel curved balloon catheter might be used for implantation of the short stent in a curved lesion; however, it should not be used for primary stenting of the long stent. Post-dilation to conform the stent to the angled vessel would be safer than primary stenting irrespective of stent length. Copyright © 2014 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

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.

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.

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.

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.

[Stent implantation in the treatment of pharynx anastomotic stenosis after cervical esophageal resection: a case report].

PubMed

Zang, Chuanshan; Sun, Jian; Sun, Yan

2016-03-01

We report the treatment of one patient with pharynx anastomotic stenosis after cervical esophagealresection by stent implantation. The patient suffered from serious pharynx anastomotic stenosis after gastric-pha-ryngeal anastomosis. After balloon-dilatation,a domestic self-expanding Z-stents was implanted in the stricture ofthe esophagus under the X-rays. After stent implantation, the patient has been leading a normal life for threeyears. Balloon dilatation and stent implantation is an effective and safe method in the treatment of patients withpharynx anastomotic stenosis.

[Endoscopic realignment with drainage via a peel-away sheath for the treatment of urethral rupture: A report of 21 cases].

PubMed

Han, Cong-Xiang; Xu, Wei-Jie; Li, Wei; Yu, Zhong-Ying; Li, Jin-Yu; Lin, Xia-Cong; Zhao, Li

2016-07-01

To study the clinical effect endoscopic realignment with drainage via a peel-away sheath in the treatment of urethral rupture. We treated 21 urethral rupture patients by endoscopic realignment with drainage via a peel-away sheath using normal saline for irrigation under the normal nephroscope or Li Xun nephroscope, followed by analysis of the clinical results. The operation was successfully accomplished in 20 cases but failed in 1 and none experienced urinary extravasation. In the 14 cases of bulbar urethral rupture, the mean operation time was (5.1±1.6) min and the mean Foley catheter indwelling time was (26.0±5.1) d. Urethral stricture developed in 57.1% (8/14) of the cases after catheter removal, of which 1 was cured by internal urethrotomy and the other 7 by urethral sound dilation, with an average maximum urinary flow rate of (18.8±1.8) ml/s at 12 months after operation. In the 6 cases of posterior urethral rupture, the mean operation time was (15.8±7.5) min and the mean Foley catheter indwelling time was 8 weeks. Urethral stricture developed in all the 6 cases after catheter removal, of which 3 cases were cured by urethral dilation, 1 by internal urethrotomy, and 2 by open urethroplasty. The average maxium urinary flow rate of the 4 cases exempt from open surgery was (17.9±1.9) ml/s at 12 months after operation. Endoscopic realignment with drainage via a peel-away sheath can keep the operative field clear, avoid intraoperative rinse extravasation, shorten the operation time, improve the operation success rate, and achieve satisfactory early clinical outcomes in the treatment of either bulbar or posterior urethral rupture.

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

The effect of nitroglycerin on the IUD insertion experience in nulliparous women: a pilot study.

PubMed

Micks, Elizabeth A; Jensen, Jeffrey T; Bednarek, Paula H

2014-07-01

Concern about pain during placement of an intrauterine device (IUD) represents a barrier to use, especially among nulliparous women. We hypothesized that nitroglycerin gel applied vaginally 30 min prior to IUD placement would reduce insertion-related pain. We designed a randomized, double-blinded, placebo-controlled pilot study to evaluate the efficacy and tolerability of 0.5-mg nitroglycerin gel (1 mL) or identical placebo gel applied vaginally in nulliparous women 30 min prior to IUD placement. The study was limited to women who opted for the levonorgestrel-releasing intrauterine system. Subjects completed a series of 100-mm visual analogue scales at several time points. The primary outcome was subject-reported pain with passage of the IUD through the cervix. Secondary outcomes included subject-reported pain at other time points, provider-reported ease of insertion, side effects, adverse events and need for additional dilation. A total of 24 women were randomized. Baseline characteristics were similar between groups. The mean pain score with IUD deployment was 55.0 mm [standard deviation (SD) = 29.7 mm] in the placebo group and 57.4 mm (SD 22.1 mm) in the nitroglycerin group (p=.82). There was no difference in ease of insertion reported by providers. Two subjects required dilation, one in each group. Vaginal administration of 0.5-mg nitroglycerin gel 30 min prior to IUD placement does not appear to decrease patient-reported procedural pain among nulliparous women or ease of insertion for providers. Copyright © 2014 Elsevier Inc. All rights reserved.

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 ...

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

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.

Spherical combustion clouds in explosions

NASA Astrophysics Data System (ADS)

Kuhl, A. L.; Bell, J. B.; Beckner, V. E.; Balakrishnan, K.; Aspden, A. J.

2013-05-01

This study explores the properties of spherical combustion clouds in explosions. Two cases are investigated: (1) detonation of a TNT charge and combustion of its detonation products with air, and (2) shock dispersion of aluminum powder and its combustion with air. The evolution of the blast wave and ensuing combustion cloud dynamics are studied via numerical simulations with our adaptive mesh refinement combustion code. The code solves the multi-phase conservation laws for a dilute heterogeneous continuum as formulated by Nigmatulin. Single-phase combustion (e.g., TNT with air) is modeled in the fast-chemistry limit. Two-phase combustion (e.g., Al powder with air) uses an induction time model based on Arrhenius fits to Boiko's shock tube data, along with an ignition temperature criterion based on fits to Gurevich's data, and an ignition probability model that accounts for multi-particle effects on cloud ignition. Equations of state are based on polynomial fits to thermodynamic calculations with the Cheetah code, assuming frozen reactants and equilibrium products. Adaptive mesh refinement is used to resolve thin reaction zones and capture the energy-bearing scales of turbulence on the computational mesh (ILES approach). Taking advantage of the symmetry of the problem, azimuthal averaging was used to extract the mean and rms fluctuations from the numerical solution, including: thermodynamic profiles, kinematic profiles, and reaction-zone profiles across the combustion cloud. Fuel consumption was limited to ˜ 60-70 %, due to the limited amount of air a spherical combustion cloud can entrain before the turbulent velocity field decays away. Turbulent kinetic energy spectra of the solution were found to have both rotational and dilatational components, due to compressibility effects. The dilatational component was typically about 1 % of the rotational component; both seemed to preserve their spectra as they decayed. Kinetic energy of the blast wave decayed due to the pressure field. Turbulent kinetic energy of the combustion cloud decayed due to enstrophy overline{ω 2} and dilatation overline{Δ 2}.

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.