SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Dilation

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Balloon dilation may offer a more expedient and cost-effective treatment method compared with traditional endoscopic sinus surgery for chronic maxillary atelectasis. We sought to demonstrate the feasibility of balloon dilation of the maxillary os as a treatment modality for patients with chronic maxillary atelectasis by investigating the short-term outcomes in a retrospective case series of 4 patients representing 5 sinuses treated between 2011 and 2013. All sinuses were successfully balloon dilated without complications. Follow-up ranged from 1 week to 4 months. Aeration of the treated sinuses without restenosis was confirmed by postoperative endoscopy, sinus computed tomography, or both. All patients reported subjective symptomatic improvement. Balloon dilation of the maxillary os may be a feasible treatment option for maxillary sinus atelectasis. Longer follow-up and a larger study sample will be needed to validate the safety of this technique and determine the rate of restenosis.

Concepts: Sinusitis, Retrospective, Maxillary sinus, Endoscopy, Case series, Dilation, Cervical dilation

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BACKGROUND: Endosonography (EUS)-guided transmural pseudocyst drainage is a multistep procedure currently performed with different “off-the-shelf” accessories developed for other applications. Multiple device exchanges over-the-wire is time consuming and risks loss of wire access. This report describes the technical feasibility and outcomes for EUS-guided drainage of pancreatic fluid collections using a novel exchange-free device developed for translumenal therapy. METHODS: Between April and November 2010, 14 patients (9 men; mean age, 49.9 years) with pancreatic fluid collection (mean size, 102 mm) underwent 16 EUS-guided drainage procedures using the exchange-free access device at a single tertiary care center. The trocar of the exchange-free device was used to gain pseudocyst access. The dual-balloon catheter then was advanced over the trocar, followed by inflation of the (first) anchor balloon. Cyst contents were sampled, and contrast was injected to define the pseudocyst anatomy. The first guidewire was inserted into the cyst cavity. The cystenterostomy tract was dilated to 10 mm with the (second) dilation balloon, followed by a second guidewire insertion. The exchange-free access device was removed, leaving the two guidewires in place for two double-pigtail stents. RESULTS: The procedure was technically successful for all the patients. No acute procedure-related complications occurred. Late complications included a symptomatic leak in a patient who underwent drainage of a pancreatic uncinate pseudocyst from the second duodenum, a self-limited transfusion-dependent bleed after transbulbar drainage, and symptomatic pseudocyst infection. CONCLUSION: Pseudocyst access, cystenterostomy tract dilation, and placement of two guidewires for dual stent drainage are technically feasible using an exchange-free access device. The device has the potential to standardize, simplify, and streamline EUS-guided pseudocyst drainage with a single instrument. Comparative studies with alternative tools and methods for pseudocyst drainage are warranted.

Concepts: Stent, Tertiary referral hospital, Sebaceous cyst, Cyst, Pancreatic pseudocyst, Pseudocyst, Dilation

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The aim of this prospective study was to characterise patient characteristics and the histories of cats with acquired nasopharyngeal stenosis (ANS), and to describe the use of a removable silicone stent for treatment. ANS was diagnosed in 15 cats with clinical signs present for a median of 4 months. Clinical signs included stertor and inspiratory difficulty, nasal discharge, sneezing, dysphagia, regurgitation, vomiting and anorexia. Radiographs revealed a dorsal deviation or deformation of the caudal part of the soft palate in 10 of the cats, a soft tissue density across the cranial nasopharynx in four and no abnormality in one. The stenosis was initially dilated with a Kelly forceps in 10 of the cats and by balloon dilatation in five. A segment of a 24 Fr silicone thoracic catheter was used for the stent in five cats; in the other 10 cats a segment of a 28 Fr catheter was used. The stent was removed after 3 weeks in 12 cats and after 4 weeks in the other three. Endoscopy revealed an adequate nasopharyngeal diameter in all of the cats. At both 3 and 10 months after surgery the response was considered to be satisfactory, with complete resolution of clinical signs in 14 cats and improvement in the remaining cat. The treatment of ANS by stenosis dilatation followed by temporary stenting with a silicone stent is a rapid, safe, economical and effective procedure.

Concepts: Stent, Soft tissue, Nasopharynx, Soft palate, Palate, Hard palate, Levator veli palatini, Dilation

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Dilated cardiomyopathy is characterised by dilation and impaired systolic function. We present the case of a child with dilated cardiomyopathy caused by a 624 kb duplication of 6q22.31, which includes the phospholamban gene. The patient also has failure to thrive and developmental delay due to complex cytogenetic abnormalities including a 5p15 deletion associated with Cri du Chat and an 11p15 duplication associated with Russell-Silver syndrome.

Concepts: DNA, Genetics, Chromosome, Cytogenetics, Down syndrome, Genetic disorders, Dilation

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We have all experienced that time seems stretched during unpleasant situations. While there is evidence of subjective time overestimation when perceiving external unpleasant stimuli, no study has measured the dilation of time when individuals experience an unpleasant situation in their own body. Here we measured the time dilation induced by a painful homeostatic deviance using temporal bisection task. We show that being in pain leads to an expansion of subjective time whereby a stronger increase in pain perception relative to non-painful stimulation leads to a stronger time-estimate distortion. Neurophysiological studies suggest that time estimation and the perception of self might share a common neural substrate. We propose that, along with bodily arousal and attentional capture, the enhancement of self-awareness may be critical to support dilated subjective time when experiencing pain. As other homeostatic deviances, pain may induce a focus on ourselves contributing to the impression that “time stands still”.

Concepts: Time, Psychology, Perception, Pain, Experience, Unsolved problems in neuroscience, Suffering, Dilation

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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 ACOG/SMFM 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 directly related to labor progress. At each examination the calculations adapt to the mother’s current labor conditions. They produce a quantitative assessment expressed in percentiles. Low percentiles indicate potentially problematic labor progression.

Concepts: Scientific method, Statistics, Sociology, Accuracy and precision, Quantitative research, Dilation, Cervical dilation

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This study introduces an automated pairwise method for osteological pair-matching of fragmented skeletal remains using two-dimensional fragmented outlines extracted from photographs. The form data are used in pairwise iterative closest point registrations with rigid transformations. A modified version of the average Hausdorff distance is calculated to remove any coordinate correspondences with outline fracture margins, which allow the distance analysis of fragmented outlines. A dilation modification to the Hausdorff distance is proposed creating a greater separation between true- and false-pairs. The sample consists of 122 calcanei (61 pairs) from the UI-Stanford collection. Performance statistics are provided for simulated fragmented and complete assemblages. Results indicate up to 98% accuracy for fragmented and complete assemblages. The dilated Hausdorff distance performed similarly across assemblages, but showed a slight decrease in performance for the complete assemblage. This approach provides a useful short listing tool to reduce the number of visual comparisons required in large commingled assemblages.

Concepts: Bone, Performance, Metric space, Hausdorff distance, Dilation, Iterative Closest Point, Felix Hausdorff

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The human nose can expand either actively or passively to increase airflow. Nasal dilation may alter drug delivery efficiencies in the nasal airway or olfactory region. However, the dosage enhancement from nasal dilations has not been quantified. The mechanisms underlying the dilation-induced deposition variation are also not clear. This study aims to quantify the nasal dilation effects on drug delivery in the nasal airway and olfactory region using in vitro tests and numerical analysis. Two variants of an existing normal nasal airway model were developed with different levels of airway dilation. Airway dimensions were quantified in terms of hydraulic diameter, cross-sectional area, and surface area to volume ratio. Sectional nose casts were prepared using a 3-D printer for visualizing deposition patterns and quantifying delivered dosages. A well-validated computational fluid-particle dynamics (CFPD) model was utilized to understand the underlying mechanisms in the unilateral and bi-directional deliveries. In vitro tests show that nasal dilation lowered the total dosage in the nose but increased the dosage to the olfactory region in both the unilateral and bi-directional deliveries. Compared to the normal nose with unilateral delivery, nasal dilation enhanced the olfactory deposition by a factor of 2.2, while nasal dilatation with the bi-directional delivery increased by a factor of 4. Complementary numerical analyses revealed the growth of a recirculation zone in the middle meatus of dilated noses, which induced lower pressure and increased ventilation to the upper nose. In bi-directional deliveries, a significantly higher fraction of airflow was ventilated to the upper airway in the outflow side of the nose and contributed to the elevated olfactory dosage. Nasal dilation in combination with the bi-directional delivery is recommended over the conventional unilateral method for olfactory targeting.

Concepts: Respiratory system, Nose, Numerical analysis, Area, Nostril, Dilation, Human nose

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Recently, the vasodilator relaxin 2 has been introduced as a treatment for acute heart failure. However, its role on vessels of the eye and intraocular pressure (IOP) remains unclear though it has been hypothesized to induce a decrease IOP after intramuscular injection in humans. We aimed to test whether the hormone relaxin 2 lowers IOP and dilates retinal vessels in animals.

Concepts: Testosterone, Intraocular pressure, Route of administration, Routes of administration, Dilation

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Glomerular hyperfiltration often occurs during the early stage of diabetes. An acute glucose infusion increases glomerular filtration rate (GFR). The involvement of tubuloglomerular feedback response and direct effect of glucose on the afferent arterioles (Af-Arts) have been suggested. However, the signaling pathways to trigger Af-Art dilatation have not been fully identified. Therefore, in the present study we tested our hypothesis that an increase of glucose concentration enhances endothelial nitric oxide synthesis (NOS3) activity and dilates the Af-Arts via glucose transporter 1 (GLUT1) using isolated mouse Af-Arts with perfusion. We isolated and microperfused the Af-Arts from non-diabetic C57BL/6 mice. The Af-Arts were preconstricted with norepinephrine (NE, 1 µM). When we switched the D-glucose concentration from low (5 mM) to high (30 mM) in the perfusate, the preconstricted Af-Arts significantly dilated by 37.8{plus minus}7.1%, but L-glucose did not trigger the dilation. GLUT1 mRNA was identified in microdisserted Af-Arts measured by RT-PCR. Changes in nitric oxide (NO) production in Af-Art was also measured using fluorescent probe when ambient glucose concentration was increased. When the D-glucose concentration was switched from 5 to 30 mM, NO generation in Af-Art was significantly increased by 19.2{plus minus}6.2% (84.7{plus minus}4.1 to 101.0{plus minus}9.3 units/min). L-glucose had no effect on the NO generation. A GLUT1 selective antagonist, STF-31, and a nitric oxide synthase inhibitor L-NG-Nitroarginine Methyl Ester blocked the high glucose-induced NO generation and vasodilation. In conclusion, we demonstrated that an increase in glucose concentration dilates the Af-Art by stimulation of the endothelium derived NO production mediated by GLUT1.

Concepts: Glucose, Blood vessel, Endothelium, Nitric oxide, Vasodilation, Nitric oxide synthase, Dilation