Course Of Dilatation Research Articles

Time course of optic nerve sheath dilation: In vitro response characteristics to controlled pressure elevations

BackgroundOptic nerve sheath (ONS) dilation indicates intracranial pressure elevation under clinical conditions but limited data exist with regard to the dynamics of sheath expansion. ObjectiveTo assess the time course of ONS widening and its stability under controlled pressure conditions in vitro. MethodsPre-defined pressure steps up to 65 mmHg were applied to the perineural space of ex-vivo human optic nerves (n = 16). Using ultrasound, the optic nerve sheath diameter (ONSD) was monitored over 500 s. Re-tests at low-pressure levels concluded each experimental series. ResultsIn most cases, 50% of the total diameter-change were achieved within 50 s after pressure onset and 95% of the maximal diameter after 200 s. The diametric gains in each experiment were strongly correlated with the applied pressure levels (coefficient of variance 0,96) within preparations with variability of the transfer function across preparations. The time course of the dilation was found to follow an approximate natural logarithmic function (R2 = 0.93–0.99). The re-test condition revealed unchanged time course properties (5% significance level) despite starting regularly from a higher baseline-diameter after preceding exposures. ConclusionsONS dilation commences rapidly after pressure exposure with a predictable time course over 3–4 min. Elasticity changes presumably affecting trabecular structures cause upward shifts of the optic nerve sheath pressure response. Clinically, ONSD shifts should be considered in serial measurements for increasing intracranial pressure monitoring, but relevant response delays are absent for lower or higher changes of intracranial pressure.

Individual Variations in Effort: Assessing Pupillometry for the Hearing Impaired.

Assessing effort in speech comprehension for hearing-impaired (HI) listeners is important, as effortful processing of speech can limit their hearing rehabilitation. We examined the measure of pupil dilation in its capacity to accommodate the heterogeneity that is present within clinical populations by studying lexical access in users with sensorineural hearing loss, who perceive speech via cochlear implants (CIs). We compared the pupillary responses of 15 experienced CI users and 14 age-matched normal-hearing (NH) controls during auditory lexical decision. A growth curve analysis was applied to compare the responses between the groups. NH listeners showed a coherent pattern of pupil dilation that reflects the task demands of the experimental manipulation and a homogenous time course of dilation. CI listeners showed more variability in the morphology of pupil dilation curves, potentially reflecting variable sources of effort across individuals. In follow-up analyses, we examined how speech perception, a task that relies on multiple stages of perceptual analyses, poses multiple sources of increased effort for HI listeners, wherefore we might not be measuring the same source of effort for HI as for NH listeners. We argue that interindividual variability among HI listeners can be clinically meaningful in attesting not only the magnitude but also the locus of increased effort. The understanding of individual variations in effort requires experimental paradigms that (a) differentiate the task demands during speech comprehension, (b) capture pupil dilation in its time course per individual listeners, and (c) investigate the range of individual variability present within clinical and NH populations.

A randomized controlled trial of endoscopic steroid injection for prophylaxis of esophageal stenoses after extensive endoscopic submucosal dissection.

BackgroundEsophageal stenosis following endoscopic submucosal dissection (ESD) is a serious adverse event that makes subsequent management more difficult.MethodsThis parallel, randomized, controlled, open-label study was designed to examine whether local steroid injection is an effective prophylactic treatment for esophageal stenoses following extensive ESD. This single center trial was conducted at the Keiyukai Hospital, a tertiary care center for gastrointestinal disease in Japan [University Hospital Medical Network Clinical Trial Registry (UMIN-CTR) on 15 September 2011 (UMIN000006327)]. Thirty-two patients with mucosal defects involving ≥75% of the esophageal circumference were randomized to receive a single dose of triamcinolone acetonide injections (n = 16) or be treated conventionally (n = 16). The primary outcome was the frequency of stricture requiring endoscopic dilatation; the surrogate primary endpoint was the number of dilatation sessions needed. Secondary outcomes included adverse event rates, the minimum diameter of the stenotic area and the duration of the course of dilatation treatments.ResultsThe frequency of stricture was not significantly different between the groups because of insufficient statistical power, but the number of dilatation sessions required was significantly less in the steroid group (6.1 sessions [95% confidence interval, CI 2.8–9.4] versus 12.5 [95% CI 7.1–17.9] sessions in the control group; P = 0.04). The perforation rate was similar in both groups. The minimum diameter of stenotic lumens was significantly greater in the treatment group than controls (11.0 mm versus 7.1 mm, respectively; P = 0.01). The perforation rate was not significantly different between the groups (1.0% versus 0.5% in the treatment and control group, respectively). Steroid injection was effective in cases of mucosal defects encompassing the entire esophageal circumference.ConclusionsProphylactic endoscopic steroid injection appears to be a safe means of relieving the severity of esophageal stenoses following extensive ESD.

PTU-161 Endoscopic Bougie Dilatation Is Effective And Safe For Oes Ophageal And Pharyngeal Strictures: Outcomes Of A Large Case Series

IntroductionEndoscopic bougie dilatation is a traditional technique for managing oesophageal strictures. There are some safety concerns with this technique, but no corroborative evidence of this in controlled or uncontrolled studies...

Dynamic Changes of Common Bile Duct Diameter During an Episode of Biliary Colic, Documented by Ultrasonography

Common bile duct stones frequently accompany gallstones and can be identified by a variety of imaging modalities. Little is known about the time course of dilatation of the common bile duct after acute obstruction or of normalization after spontaneous passage of an obstructing stone. We describe a case showing rapid fluctuations in common bile duct diameter during 72 hours in a patient presenting with epigastric pain and vomiting. Initial emergency bedside ultrasonography revealed a distended gallbladder, a dilated common bile duct (17 mm), and an obstructing stone. Five hours later, ultrasonography performed in the radiology suite showed a normal common bile duct diameter (4 mm) and no obstructing stone. The patient was admitted, and during the course of hospitalization different imaging modalities reported fluctuations in common bile duct measurements, ranging from 4 mm on computed tomography to 14 mm on endoscopic retrograde cholangiopancreatography. This case demonstrates disappearance of an obstructing stone with normalization of a highly distended common bile duct during 5 hours, highlighting that gallstone disease may be highly dynamic, with the possibility of rapid changes of common bile duct diameter. Emergency physicians, who frequently depend on ultrasonography to diagnose biliary disease, should be wary of the potential for rapid changes of sonographic findings in these patients.

Chronic diet-induced hyperhomocysteinemia impairs eNOS regulation in mouse mesenteric arteries

Hyperhomocysteinemia (HHcy) impairs endothelium-dependent vasodilation by increasing reactive oxygen species, thereby reducing nitric oxide (NO.) bioavailability. It is unclear whether reduced expression or function of the enzyme that produces NO., endothelial nitric oxide synthase (eNOS), also contributes. It is also unclear whether resistance vessels that utilize both NO.and non-NO.vasodilatory mechanisms, undergo alteration of non-NO.mechanisms in this condition. We tested these hypotheses in male C57BL/6 mice with chronic HHcy induced by 6-wk high methionine/low-B vitamin feeding (Hcy: 89.2 +/- 49.0 microM) compared with age-matched controls (Hcy: 6.6 +/- 1.9 microM), using first-order mesenteric arteries. Dilation to ACh (10(-9)-10(-4) M) was measured in isolated, cannulated, and pressurized (75 mmHg) arteries with and without N(G)-nitro-l-arginine methyl ester (l-NAME) (10(-4) M) and/or indomethacin (10(-5) M) to test endothelium-dependent dilation and non-NO.-dependent dilation, respectively. The time course of dilation to ACh (10(-4) M) was examined to compare the initial transient dilation due to non-NO., non-prostacyclin mechanism and the sustained dilation due to NO.. These experiments indicated that endothelium-dependent dilation was attenuated (P < 0.05) in HHcy arteries due to downregulation of only NO.-dependent dilation. Western blot analysis indicated significantly less (P < 0.05) basal eNOS and phospho-S1179-eNOS/eNOS in mesenteric arteries from HHcy mice but no difference in phospho-T495-eNOS/eNOS. S1179 eNOS phosphorylation was also significantly less in these arteries when stimulated with ACh ex vivo or in situ. Real-time PCR indicated no difference in eNOS mRNA levels. In conclusion, chronic diet-induced HHcy in mice impairs eNOS protein expression and phosphorylation at S1179, coincident with impaired NO.-dependent dilation, which implicates dysfunction in eNOS post-transcriptional regulation in the impaired endothelium-dependent vasodilation and microvascular disease that is common with HHcy.

Management of Acid- and Alkali-Induced Esophageal Strictures in 79 Adults by Endoscopic Dilation: 8-Years’ Experience in New Delhi

Experience with endoscopic dilation of acid- and alkali-induced strictures of the esophagus using Savary-Gilliard (SG) and balloon dilators is limited, especially in adults. The aim of this study was to determine the safety and efficacy of endoscopic dilation in the management of corrosive esophageal strictures and to compare results with regard to acid- vs. alkali-induced strictures. The records of 230 patients who were treated by endoscopic dilation between 1997 and 2005 at our center were reviewed. This study included all the patients who had corrosive-induced esophageal strictures. SG dilators were used in most of our patients [67/79 (85%)], while only a few patients [12/79 (15%)] were treated with balloon dilators. Dilation was found to be successful after an initial course of dilation (not requiring further dilations) in 28/37 (75.67%) cases in the SG dilator group and in 9/12 (75%) in the balloon group. Strictures caused by acids required a greater mean number of dilations for initial relief of dysphagia compared with that for alkalis. Some of these patients responded to a second course of dilation, leading to final combined SG dilator and balloon dilator success rates of 24/28 (86%) in the acid group and 17/21 (81%) in the alkali group. A total of 359 sessions of dilations were performed with a complication rate of 2/359 (0.56%). Endoscopic dilation using Savary-Gilliard and balloon dilators is safe and effective in managing corrosive esophageal strictures, but it is operator-dependent and the final outcome depends largely on the technical expertise and appropriate selection of patients.

Home-dilatation of the urethral meatus in boys.

To evaluate the efficacy of dilatation of the stenotic urethral meatus in boys at home. Eighteen boys aged 3-15 years, or their parents, were taught to dilate the urethral meatus at home. The cause of the stricture was balanitis xerotica obliterans (BXO) in five and consequent upon hypospadias surgery in 12, of whom two were complicated by BXO, and one after circumcision for cultural reasons. One boy was re-referred after an interval of 3 years because of apparent deterioration of the stream of urine. Meatal dilatation was taught in the home by one of the authors (J.M.S.). Nine patients were cured by the first course of dilatation, four relapsed early after initial success but responded to further treatment, and three proceeded to meatoplasty because they had no response. Two relapsed late and one responded to further dilatation but the other required surgery. Dilatation of the urethral meatus can be taught successfully to boys or their families at home, thus avoiding repeated hospital attendance and often general anaesthesia.

Endoscopic balloon dilation of esophageal strictures in children.

A total of 17 patients, ages 3 weeks to 14 1/2 years, had 20 esophageal strictures develop after repair of esophageal atresia (9 strictures); primary gastroesophageal reflux (3 strictures); Nissen fundoplication (4 strictures); epidermolysis bullosa congenita dystrophica (1 stricture); congenital esophageal stenosis (2 strictures); or colonic interposition (1 stricture). These strictures were treated with 132 endoscopic balloon catheter dilations (average, 6.6/patient, range, 1 to 24) during a period of 42 months (average, 8 months; range, 2 to 42 months). Fifteen of the 17 patients are now asymptomatic. Thirteen of the 17 patients had documented reflux esophagitis and were also medically treated. The two residually symptomatic patients included a patient with severe proximal esophagitis secondary to epidermolysis bullosa congenita dystrophica who had only a temporary response to dilations and another patient with a tight Nissen fundoplication who did not improve after dilation but is now asymptomatic after corrective surgery. The 10 patients with tracheoesophageal fistula repair were asymptomatic within 3 to 21 months (average, 10.8 months). Only one patient had perforation develop as a result of the procedure. Sixteen of 17 patients had the procedures performed as outpatients. All patients were given oral feedings throughout the course of dilation and had normal growth.

Hydronephrosis of pregnancy: a prospective sequential study of the course of dilatation.

The kidneys of 20 asymptomatic pregnant women were examined sequentially from the first trimester through the postpartum period. In 41.5 per cent, progressive dilatation, more marked on the right side, was seen; however, the remainder demonstrated varying, static, or even diminishing ectasia. In all but two dilatation had reverted to normal by six weeks post partum. The finding of minimal dilatation speaks against pathologic obstruction even in the symptomatic patient. Asymptomatic patients can, however, show variable degrees of hydronephrosis with progression or regression through the course of gestation. The finding of dilatation must be interpreted with caution by virtue of these sequential variations.

Graviditätsbedingte Erweiterungen am Nierenhohlsystem Sonographische Diagnose und Verlaufskontrollen

Ultrasonic diagnosis provides the possibility without any irradiation hazards to follow-up the urinary excreting system in pregnancies as often as necessary. Thus it becomes possible to detect the true percentages of pregnant women with dilatation of the calyceal system, and to evaluate the course of dilatation in those women examined at different intervals. There exists as well the possibility to avoid urinary tract infections by an intensive urologic surveillance in such cases.