Comparison of open and laparoscopic pyeloplasty in ureteropelvic junction obstruction surgery: report of 49 cases.

PubMed

Umari, Paolo; Lissiani, Andrea; Trombetta, Carlo; Belgrano, Emanuele

2011-12-01

This study aimed to evaluate laparoscopic dismembered pyeloplasty compared with open surgery and to determine whether the morbidity and outcome rates are different in each of these techniques. We report our 10-year experience with open and laparoscopic pyeloplasty at one istitution. From February 1999 to October 2010, 49 patients with ureteropelvic junction obstruction were assigned into two groups. 25 patients underwent open surgical pyeloplasty (period 1999-2010) and 24 underwent laparoscopic pyeloplasty (period 2004-2010). 25 patients undergoing open pyeloplasty had a retroperitoneal flank approach. Of the 24 laparoscopic cases 18 had a transperitoneal retrocolic access, 1 had a transperitoneal transmesocolic access and 5 had a retroperitoneal access. In all 49 cases an Anderson-Hynes dismembered pyeloplasty was used. We retrospectively compared the operative time, hospital stay, perioperative complications and follow-up of the two groups. Clinical symptoms were assessed before and after surgery, subjectively. Patients dermographic data were similar between the two groups with mean age of 42 years (range 6-78) and with a male/female ratio of 1:1.45. A crossing vessel could be identified in 37.5% (9/24) with laparoscopy vs. 32% (8/25) in open surgery. Compared with open procedures, laparoscopic procedures were associated with a longer mean operating time (274 vs 143 min), a shorter mean hospital stay (9.9 vs 15.8 day) and the perioperative complication rates were 16.7% for laparoscopic pyeloplasties and 20% for open pyeloplasties. The success rates were 90.5% for laparoscopy and 90.9% for open surgery. Average follow-up was 40.9 month for the laparoscopic group and 72.3 month for the open group. Failed procedures showed no improvement in loin pain or obstruction. The efficacy (in term of success rate and perioperative complications) of laparoscopic pyeloplasty is comparable to that of open pyeloplasty, with shorter mean hospital stay and better cosmetic results. These findings may suggest, that the laparoscopic dismembered pyeloplasty has the potential to replace open surgery and may be considered the first option for the treatment of ureteropelvic junction obstruction in expert hands.

Congenital ureteropelvic junction obstruction: physiopathology, decoupling of tout court pelvic dilatation-obstruction semantic connection, biomarkers to predict renal damage evolution.

PubMed

Alberti, C

2012-02-01

The widespread use of fetal ultrasonography results in a frequent antenatally observation of hydronephrosis, ureteropelvic junction obstruction (UPJO) accounting for the greatest fraction of congenital obstructive nephropathy. UPJO may be considered, in most cases, as a functional obstructive condition, depending on defective fetal smooth muscle/nerve development at this level, with lack of peristaltic wave propagation--aperistaltic segment--and, therefore, poor urine ejection from the renal pelvis into the ureter. The UPJO-related physiopathologic events are, at first, the compliant dilatation of renal pelvis that, acting as hydraulic buffer, protects the renal parenchyma from the rising intrapelvic pressure-related potential damages, and, subsequently, beyond such phase of dynamic balance, the tubular cell stretch-stress induced by increased intratubular pressure and following parenchymal inflammatory lesions: inflammatory infiltrates, fibroblast proliferation, activation of myofibroblasts, tubulo-interstitial fibrosis. Reactive oxygen species (ROS), nitric oxide (NO), several chemo- and cytokines, growth factors, prostaglandins and eicosanoids, angiotensin-II are the main pathogenetic mediators of the obstructive nephropathy. Apoptosis of tubular cells is the major cause of the tubular atrophy, together with epithelial-mesenchymal transdifferentiation. Some criticisms on tout court semantic renal pelvis dilatation-obstruction connection have been raised considering that the renal pelvis expansion isn't, in any case, linked to an ostructive condition, as it may be verified by diuretic (furosemide) renogram together with scintiscan-based evaluation of differential renal function. In this regard, rather than repetitive invasive nuclear procedures that expose the children to ionizing radiations, an intriguing noninvasive strategy, based on the evaluation of urinary biomarkers and urinary proteome, can define the UPJO-related possible progress of parenchymal lesions, thus predicting which patients must require an obstruction correcting surgery and in which patients, instead, the hydronephrosis will spontaneously resolve.

Laparoscopic pyeloplasty: technique and results in 80 consecutive patients.

PubMed

Castillo, O A; Cabrera, W; Aleman, E; Vidal-Mora, I; Yañez, R

2014-03-01

To present our long-term results with the Anderson-Hynes laparoscopic pyeloplasty, performed by a single surgeon. Between August 1999 and December 2009, 79 patients (80 procedures) were operated for primary ureteropelvic junction obstruction. We use the Anderson-Hynes technique by a transperitoneal approach. Patients were evaluated with Ultrasound, Excretory urography and dynamic renal scintigraphy (Mag-3). The perioperative characteristics, complications and results were reviewed. We performed 80 laparoscopic pyeloplasties in 79 patients. Mean operative time was 93.2 minutes (60-180). Crossing vessels were found in 38 of 82 (46.3%) renal units. Kidney abnormalities occurred in 4 patients (1 double ureteropelvic system, one associated retrocaval ureter, 1 horseshoe kidney and one pelvic kidney). Complications occurred in 5 procedures (6.5%): an immediately postoperative bleeding (Clavien 3b), 1 cecal volvulus (Clavien 3b), 1 urosepsis (Clavien 4th) and 1 urinary fistula (Clavien 3a). In this series there was neither mortality nor conversion to open surgery There was recurrence in 3 out of 80 patients (3.7%). They were resolved as follows: 1 percutaneous antegrade endopyelotomy, 1 secondary laparoscopic pyeloplasty and 1 robotic pyeloplasty. There was a 96.3%. of primary overall success rate. Our results show that laparoscopic pyeloplasty compares favorably with the result achieved by open surgery. We believe that laparoscopic pyeloplasty is a good surgical alternative for the management of primary ureteropelvic junction obstruction. Copyright © 2013 AEU. Published by Elsevier Espana. All rights reserved.

Retrograde endopyelotomy: a comparison between laser and Acucise balloon cutting catheter.

PubMed

el-Nahas, Ahmed R

2007-03-01

Endopyelotomy and laparoscopic pyeloplasty are the preferred modalities for treatment of ureteropelvic junction obstruction because of their minimally invasive nature. There are continuous efforts for improving endopyelotomy techniques and outcome. Retrograde access represents the natural evolution of endopyelotomy. The Acucise cutting balloon catheter (Applied Medical Resources Corp., Laguna Hills, CA) and ureteroscopic endopyelotomy using holmium laser are the most widely accepted techniques. The Acucise catheter was developed to simplify retrograde endopyelotomy and made it possible for all urologists, regardless of their endourologic skills. The Acucise catheter depends on incision and dilatation of the ureteropelvic junction under fluoroscopic guidance, whereas ureteroscopy allows visual control of the site, depth, and extent of the incision; the holmium laser is a perfect method for a clean precise incision. Review of the English literature showed that the Acucise technique was more widely performed, though laser had better (but not statistically significant) safety and efficacy profiles.

Fibroepithelial ureteral polyps presenting as ureteropelvic obstruction

PubMed Central

Cusano, Antonio; Abarzua-Cabezas, Fernando; Kesler, Stuart

2014-01-01

A 57-year-old woman presented with bilateral abdominal pain and flank discomfort. Imaging studies, consisting of CT scan, diethylene triamine pentaacetic acid renal scan with Lasix and a retrograde pyelogram, indicated an obstruction at the uteropelvic junction (UPJ), possibly due to fibroepithelial polyps within the ureter. A robotic pyeloplasty revealed a ureteral diverticulum and a thin, still-attached fibroepithelial polyp of approximately 2 cm in length. The patient tolerated the procedure well and was discharged one day postpyeloplasty with no reported complications. This rare clinical scenario should be considered when formulating a diagnosis for a UPJ obstruction. PMID:24759168

[Clinical results of percutaneous pyeloplasty for ureteropelvic junction obstruction: 5 years follow-up].

PubMed

Nishio, S; Hamada, S; Nabeshima, S; Yokoyama, M; Takeuchi, M; Takeda, H

1994-11-01

We performed percutaneous endopyeloplasty on 20 patients between February, 1988 and July, 1993. Eighteen patients had primary and two had secondary ureteropelvic junction (UPJ) obstructions. There were 15 female and 5 male patients, whose ages ranged from 14 to 77, with an average of 43.6. The length of the follow-up after pyeloplasty ranged from 4 to 69 months with an average of 28.7 months. Among the 20 patients, there were 4 high insertion type cases, a bifid renal pelvis in one case and one case combined with a renal stone. Incisions were made with a hook-shaped cold knife and Ono's transpelvic extraureteral approach was used in most patients. Catheters were placed at the upper and the lower of renal pelvis in the patient with a bifid renal pelvis. In the case with a renal stone, pyeloplasty was successively performed after percutaneous nephrolithotomy in a single session. An endopyelotomy stent (14 Fr) was indwelled for 6 weeks in all patients except one. All patients had a low grade fever and abdominal pain for a few days after their operations, but there were no major complications. In nineteen patients (95%), the symptoms improved and their obstructive patterns disappeared or improved during follow-up. Complete ureteral stricture was found in one case at the removal of the stent and open pyeloplasty was performed. Percutaneous endopyeloplasty is a safe and useful technique, but further evaluation and/or better techniques are needed for avoiding recurrence of obstruction.

Retrograde Endopyelotomy with Cutting Balloon™ for Treatment of Ureteropelvic Junction Obstruction in Infants.

PubMed

Parente, Alberto; Perez-Egido, Laura; Romero, Rosa Maria; Ortiz, Ruben; Burgos, Laura; Angulo, Jose Maria

2016-01-01

The aim of this study is to analyze results of retrograde endopyelotomy with cutting balloon for treatment of ureteropelvic junction obstruction (UPJO) in infants. We routinely treat patients with UPJO under 18 months of age with retrograde high-pressure balloon dilatation of the pelviureteric junction (PUJ). During the procedure, in these cases where narrowing at the PUJ persists, endopyelotomy with cutting balloon is performed. Endopyelotomy is performed over guidewire with 5-mm Cutting Balloon™ under fluoroscopic control. Double-J stents is left in situ for 4 weeks. We retrospectively analyzed the postoperative, clinical, and radiological outcome infants treated with cutting balloon endopyelotomy between 2007 and 2015. Sixteen patients required cutting balloon endopyelotomy to achieve complete resolution of narrowing of the waist observed during high-pressure balloon dilatation of the PUJ. Mean operative time was 35 ± 21 min (mean ± SD) and hospital stay was <24 h in all patients. Complete resolution of the narrowing at the PUJ under fluoroscopy was achieved in all cases, with no perioperative complications. One patient presented with urinary tract infection, postoperatively (Clavien grade II). Preoperatively, all cases had grade IV SFU hydronephrosis with parenchymal thinning. During follow-up, resolution of the hydronephrosis was observed in 11 patients (grade I SFU). In four infants, there was an improvement of the hydronephrosis (grade II SFU) and the renogram curve. In one case, an open pyeloplasty was required due to persistent hydronephrosis and obstructive curve. We believe that endopyelotomy with cutting balloon could be a valid and safe option in minimally invasive management of UPJO in infants.

Predictors of Recoverability of Renal Function after Pyeloplasty in Adults with Ureteropelvic Junction Obstruction.

PubMed

Li, Xiao-Dong; Wu, Yu-Peng; Wei, Yong; Chen, Shao-Hao; Zheng, Qing-Shui; Cai, Hai; Xue, Xue-Yi; Xu, Ning

2018-01-01

This study aimed to identify factors predicting the recoverability of renal function after pyeloplasty in adult patients with ureteropelvic junction obstruction. We retrospectively reviewed 138 adults with unilateral renal obstruction-induced hydronephrosis and who underwent Anderson-Hynes dismembered pyeloplasty from January 2013 to January 2016. Hydronephrosis was classified preoperatively according to the Society for Fetal Urology (SFU) grading system. All patients underwent Doppler ultrasonography, excretory urography, computed tomography, and technetium-99m-diethylenetriamine pentaacetic acid radioisotope (99mTc DTPA) renography before and after surgery. Renal resistive index (RRI) and 99mTc DTPA renography were repeated at 1, 3, 6, and 12 months. Multivariate analysis identified age, renal pelvic type, SFU grade, preoperative RRI, decline of RRI, and renal parenchyma to hydronephrosis area ratio (PHAR) as independent predictors of renal function recoverability after pyeloplasty. However, preoperative RRI and RRI decline were not significantly associated with recoverability of renal function in patients aged >35 years. Lower preoperative RRI, greater decline in RRI, higher PHAR, lower SFU grade, and extrarenal pelvis were associated with greater improvements in postoperative renal function. Preoperative differential renal function cannot independently predict the recoverability of postoperative renal function in adult patients with unilateral renal obstruction-induced hydronephrosis. SFU grade, renal pelvic type, PHAR, preoperative RRI, and decline in RRI were significantly associated with the recoverability of renal function in adult patients aged <35 years, while only SFU grade, renal pelvic type, and PHAR were significantly associated with renal function recoverability in patients aged ≥35 years. Renal function recovery was better in patients younger than 35 years when compared with older patients. © 2018 S. Karger AG, Basel.

Hydronephrosis in the course of ureteropelvic junction obstruction: An underestimated problem? Current opinions on the pathogenesis, diagnosis and treatment.

PubMed

Krajewski, Wojciech; Wojciechowska, Joanna; Dembowski, Janusz; Zdrojowy, Romuald; Szydełko, Tomasz

2017-08-01

Ureteropelvic junction obstruction (UPJO) causes a reduction in the urine flow from the renal pelvis into the ureter. Untreated UPJO may cause hydronephrosis, chronic infection or urolithiasis and will often result in progressive deterioration of renal function. Most cases of UPJO are congenital; however, the disease can be clinically silent until adulthood. Other causes, both intrinsic and extrinsic, are acquired and include urolithiasis, post-operative/inflammatory/ischemic stricture, fibroepithelial polyps, adhesions and malignancy. In the past, the most frequent symptom of UPJO in neonates and infants was a palpable flank mass. Nowadays, thanks to the widespread use of maternal and prenatal ultrasound examinations, asymptomatic hydronephrosis is diagnosed very early. In adults and older children symptoms may include intermittent abdominal or flank pain, nausea, vomiting and hematuria. In addition to high specificity and sensitivity in detecting UPJO, modern technologically advanced equipment such as ultrasound, magnetic resonance imaging and computed tomography provides a lot of information about the function of the affected kidney and the anatomy of the surrounding tissues. Treatment options for UPJO include a wide spectrum of approaches, from active surveillance or minimally invasive endourologic techniques to open, laparoscopic or robotic pyeloplasty. The main goal of therapy is to relieve symptoms and maintain or improve renal function, but it is difficult to define treatment success after UPJO therapy.

Concomitant treatment of ureteropelvic junction obstruction and renal calculi with robotic laparoscopic surgery and rigid nephroscopy.

PubMed

Zheng, Ji; Yan, Junan; Zhou, Zhansong; Chen, Zhiwen; Li, Xin; Pan, Jinhong; Li, Weibing

2014-01-01

The treatment of ureteropelvic junction obstruction (UPJO) and concomitant calculus poses a technically challenging situation. We present our experience with using rigid nephroscopy for renal calculi removal during robot-assisted pyeloplasy (RAP) for UPJO. From December 2010 to November 2012, 25 patients with UPJO had RAP at our institution; 9 of those had concurrent renal calculi, which were simultaneously treated with rigid nephroscopy. For stone extraction, a rigid ureteroscope was passed through an assistant trocar under laparoscopic vision directly into a previously created pyelotomy. The stones were extracted using a rigid grasper or stone basket through the rigid ureteroscope. For the removal of the stones within the upper and lower calyces, the rigid ureteroscope was introduced into the incised renal pelvis through robotic trocars if the "assistant trocar" route failed. Complete stone clearance was achieved in 8 of 9 patients. Residual calculi in 1 patient were removed with a single session of extracorporeal shock wave lithotripsy. At the mean follow-up of 10.2 months, no patients had obstruction or recurrent stones. The mean operative time was 187.1 minutes, which was 40.9 minutes longer than the mean operative time in patients without renal calculi. There was no significant difference in blood loss, hospital stay, complications, and success rates between patients with and without renal calculi. Our data suggest that the use of a concomitant rigid nephroscope and RAP is a safe and feasible option for the treatment of UPJO complicated with renal calculi. Copyright © 2014 Elsevier Inc. All rights reserved.

Resolution of Diabetes Insipidus After Pyeloplasty: A Case Report and Review of the Literature.

PubMed

Carpenter, Christina P; Rawson, Ashley; Hains, David S; Giel, Dana W

2018-05-01

Nephrogenic diabetes insipidus (NDI), a rare cause of polyuria and polydipsia in children, is usually managed with medications and careful monitoring of water intake. We present a child who was incidentally found to have right hydronephrosis secondary to ureteropelvic junction obstruction, and was subsequently also diagnosed with NDI. After being medically managed, he underwent open right pyeloplasty. His polydipsia abated within 1 month of surgery, and he has done well off of medications since that time. NDI resolution after correction of obstructive uropathy in adults has been reported, but this represents a novel case in pediatrics. Copyright © 2018 Elsevier Inc. All rights reserved.

Emergency percutaneous nephrostomy versus emergency percutaneous nephrolithotomy in patients with sepsis associated with large uretero-pelvic junction stone impaction: a randomized controlled trial.

PubMed

Hsu, Chi-Sen; Wang, Chung-Jing; Chang, Chien-Hsing; Tsai, Po-Chao; Chen, Hung-Wen; Su, Yi-Chun

2017-01-01

A randomized trial was conducted prospectively to evaluate the efficacy, related complications, and convalescence of emergency percutaneous nephrolithotomy compared to percutaneous nephrostomy for decompression of the collecting system in cases of sepsis associated with large uretero-pelvic junction stone impaction. The inclusion criteria included a WBC count of 10.000/mm3 or more and/or a temperature of 38°C or higher. Besides, all enrolled patients should maintain stable hemodynamic status and proper organ perfusions. A total of 113 patients with large, obstructive uretero-pelvic junction stones and clinical signs of sepsis completed the study protocol. Of those, 56 patients were placed in the emergency percutaneous nephrostomy group, while the other 57 patients were part of the percutaneous nephrolithotomy group. The primary end point was the time until normalization of white blood cells (WBC) at a count of 10.000/mm3 or less, and a temperature of 37.4°C or lower. The secondary end points included the comparison of analgesic consumption, length of stay, and related complications. Statistical analysis was performed using SPSS® version 14.0.1. The Mann-Whitney U test, chi-square test, and Fisher's exact test were used as appropriate. The length of hospital stays (in days) was 10.09±3.43 for the emergency percutaneous nephrostomy group and 8.18±2.72 for the percutaneous nephrolithotomy group. This set of data noted a significant difference between groups. There was no difference between groups in regard to white blood cell count (in mm3), time to normalization of white blood cell count (in days), body temperature (in ºC), time to normalization of body temperature (in days), C-reactive proteins (in mg/dL), time taken for C-reactive proteins to decrease over 25% (in days), procalcitonin (in ng/mL), or complication rates. This study confirms that emergency percutaneous nephrolithotomy may be as safe as early percutaneous nephrolithotomy in a selected low risk patients with sepsis-associated large, obstructive stone. Copyright® by the International Brazilian Journal of Urology.

Robot-assisted "Santosh-Post Graduate Institute tubularized flap pyelovesicostomy" in a solitary functioning kidney with giant hydronephrosis: A minimally invasive salvage procedure.

PubMed

Kumar, Santosh; Singh, Shivanshu; Kumar, Navneet

2016-03-01

We describe a case of a solitary functioning kidney with giant hydronephrosis secondary to ureteropelvic junction obstruction in a young girl who underwent successful robot-assisted tubularized flap pyelovesicostomy. The aim of this report was to highlight the feasibility and efficacy of this technique in salvaging such renal moieties and to present a brief review of the surgical options available for the management of giant hydronephrosis.

Proximal tubule proteins are significantly elevated in bladder urine of patients with ureteropelvic junction obstruction and may represent novel biomarkers: A pilot study.

PubMed

Gerber, Claire; Harel, Miriam; Lynch, Miranda L; Herbst, Katherine W; Ferrer, Fernando A; Shapiro, Linda H

2016-04-01

Ureteropelvic junction obstruction (UPJO) is the major cause of hydronephrosis in children and may lead to renal injury and early renal dysfunction. However, diagnosis of the degree of obstruction and severity of renal injury relies on invasive and often inconclusive renal scans. Biomarkers from voided urine that detect early renal injury are highly desirable because of their noninvasive collection and their potential to assist in earlier and more reliable diagnosis of the severity of obstruction. Early in response to UPJO, increased intrarenal pressure directly impacts the proximal tubule brush border. We hypothesize that single-pass, apically expressed proximal tubule brush border proteins will be shed into the urine early and rapidly and will be reliable noninvasive urinary biomarkers, providing the tools for a more reliable stratification of UPJO patients. We performed a prospective cohort study at Connecticut Children's Medical Center. Bladder urine samples from 12 UPJO patients were obtained prior to surgical intervention. Control urine samples were collected from healthy pediatric patients presenting with primary nocturnal enuresis. We determined levels of NGAL, KIM-1 (previously identified biomarkers), CD10, CD13, and CD26 (potentially novel biomarkers) by ELISA in control and experimental urine samples. Urinary creatinine levels were used to normalize the urinary protein levels measured by ELISA. Each of the proximal tubule proteins outperformed the previously published biomarkers. No differences in urinary NGAL and KIM-1 levels were observed between control and obstructed patients (p = 0.932 and p = 0.799, respectively). However, levels of CD10, CD13, and CD26 were significantly higher in the voided urine of obstructed individuals when compared with controls (p = 0.002, p = 0.024, and p = 0.007, respectively) (Figure). Targeted identification of reliable, noninvasive biomarkers of renal injury is critical to aid in diagnosing patients at risk, guiding therapeutic decisions and monitoring treatment efficacy. Proximal tubule brush border proteins are reliably detected in the urine of obstructed patients and may be more effective at predicting UPJO. Copyright © 2015 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

Focused ultrasound to expel calculi from the kidney: safety and efficacy of a clinical prototype device.

PubMed

Harper, Jonathan D; Sorensen, Mathew D; Cunitz, Bryan W; Wang, Yak-Nam; Simon, Julianna C; Starr, Frank; Paun, Marla; Dunmire, Barbrina; Liggitt, H Denny; Evan, Andrew P; McAteer, James A; Hsi, Ryan S; Bailey, Michael R

2013-09-01

Focused ultrasound has the potential to expel small stones or residual stone fragments from the kidney, or move obstructing stones to a nonobstructing location. We evaluated the efficacy and safety of ultrasonic propulsion in a live porcine model. Calcium oxalate monohydrate kidney stones and laboratory model stones (2 to 8 mm) were ureteroscopically implanted in the renal pelvicalyceal system of 12 kidneys in a total of 8 domestic swine. Transcutaneous ultrasonic propulsion was performed using an HDI C5-2 imaging transducer (ATL/Philips, Bothell, Washington) and the Verasonics® diagnostic ultrasound platform. Successful stone relocation was defined as stone movement from the calyx to the renal pelvis, ureteropelvic junction or proximal ureter. Efficacy and procedure time was determined. Three blinded experts evaluated histological injury to the kidney in the control, sham treatment and treatment arms. All 26 stones were observed to move during treatment and 17 (65%) were relocated successfully to the renal pelvis (3), ureteropelvic junction (2) or ureter (12). Average ± SD successful procedure time was 14 ± 8 minutes and a mean of 23 ± 16 ultrasound bursts, each about 1 second in duration, were required. There was no evidence of gross or histological injury to the renal parenchyma in kidneys exposed to 20 bursts (1 second in duration at 33-second intervals) at the same output (2,400 W/cm(2)) used to push stones. Noninvasive transcutaneous ultrasonic propulsion is a safe, effective and time efficient means to relocate calyceal stones to the renal pelvis, ureteropelvic junction or ureter. This technology holds promise as a useful adjunct to surgical management for renal calculi. Copyright © 2013 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Focused Ultrasound to Expel Calculi from the Kidney: Safety and Efficacy of a Clinical Prototype Device

PubMed Central

Harper, Jonathan D.; Sorensen, Mathew D.; Cunitz, Bryan W.; Wang, Yak-Nam; Simon, Julianna C.; Starr, Frank; Paun, Marla; Dunmire, Barbrina; Liggitt, H. Denny; Evan, Andrew P.; McAteer, James A.; Hsi, Ryan S.; Bailey, Michael R.

2015-01-01

Purpose Focused ultrasound has the potential to expel small stones or residual stone fragments from the kidney, or move obstructing stones to a nonobstructing location. We evaluated the efficacy and safety of ultrasonic propulsion in a live porcine model. Materials and Methods Calcium oxalate monohydrate kidney stones and laboratory model stones (2 to 8 mm) were ureteroscopically implanted in the renal pelvicalyceal system of 12 kidneys in a total of 8 domestic swine. Transcutaneous ultrasonic propulsion was performed using an HDI C5-2 imaging transducer (ATL/Philips, Bothell, Washington) and the Verasonics® diagnostic ultrasound platform. Successful stone relocation was defined as stone movement from the calyx to the renal pelvis, ureteropelvic junction or proximal ureter. Efficacy and procedure time was determined. Three blinded experts evaluated histological injury to the kidney in the control, sham treatment and treatment arms. Results All 26 stones were observed to move during treatment and 17 (65%) were relocated successfully to the renal pelvis (3), ureteropelvic junction (2) or ureter (12). Average ± SD successful procedure time was 14 ± 8 minutes and a mean of 23 ± 16 ultrasound bursts, each about 1 second in duration, were required. There was no evidence of gross or histological injury to the renal parenchyma in kidneys exposed to 20 bursts (1 second in duration at 33-second intervals) at the same output (2,400 W/cm2) used to push stones. Conclusions Noninvasive transcutaneous ultrasonic propulsion is a safe, effective and time efficient means to relocate calyceal stones to the renal pelvis, ureteropelvic junction or ureter. This technology holds promise as a useful adjunct to surgical management for renal calculi. PMID:23583535

Intraoperative inspection of the ureteropelvic junction during pyeloplasty is not sufficient to distinguish between extrinsic and intrinsic causes of obstruction: Correlation with histological analysis.

PubMed

Mut, Tuna; Acar, Ömer; Oktar, Tayfun; Kılıçaslan, Işın; Esen, Tarık; Ander, Haluk; Ziylan, Orhan

2016-08-01

Based on current knowledge, it is possible to have an initial diagnosis of intrinsic or extrinsic ureteropelvic junction obstruction (UPJO) based solely on clinical and imaging findings. However, it may not be possible to strictly discriminate an intrinsic case with an additional extrinsic component from a primarily intrinsic stenosis because of lower pole aberrant vessels. These two disorders may coexist or trigger each other. Herein, we aimed to compare the histological changes observed in intrinsic and extrinsic types of UPJO. Our hypothesis is that inspecting the UPJ during pyeloplasty may not be a sufficient way to delineate the underlying cause of obstruction in every individual. We retrospectively reviewed the data of 56 patients who had dismembered pyeloplasty. The intrinsic and extrinsic groups consisted of 38 and 18 patients, respectively. Masson's trichrome stain, CD117, and connexin 43 (Cx43) antibody were used in histopathology and immunochemistry. Statistical calculations were done with chi-square and Mann-Whitney U tests. Connexin 43 staining pattern, CD117 positive cell count, and the extent of fibrosis did not differ significantly between extrinsic and intrinsic cases. However, the difference with regard to the degree of muscular hypertrophy was close to statistical significance. The exact pathophysiological mechanism underlying UPJO has yet to be elucidated. A study directly comparing both groups histologically is indeed rare. Our study showed that there are no significant differences between the intrinsic and extrinsic groups in terms of the pacemaker activity, gap junctional communication, and extent of fibrosis. Muscular hypertrophy, which was marginally higher in our extrinsic group, may persist despite successful relocation of the obstructing vessel. The main drawbacks of our study are; the absence of a control group and the retrospective study design with its inherent selection biases. Immunohistochemical profiles of intrinsic and extrinsic UPJOs resemble each other. Intraoperative inspection of the UPJ may not be enough for accurate discrimination for a surgical procedure that can correct only the extrinsic cause. Copyright © 2016 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

Early Detection of Ureteropelvic Junction Obstruction Using Signal Analysis and Machine Learning: A Dynamic Solution to a Dynamic Problem.

PubMed

Blum, Emily S; Porras, Antonio R; Biggs, Elijah; Tabrizi, Pooneh R; Sussman, Rachael D; Sprague, Bruce M; Shalaby-Rana, Eglal; Majd, Massoud; Pohl, Hans G; Linguraru, Marius George

2017-10-21

We sought to define features that describe the dynamic information in diuresis renograms for the early detection of clinically significant hydronephrosis caused by ureteropelvic junction obstruction. We studied the diuresis renogram of 55 patients with a mean ± SD age of 75 ± 66 days who had congenital hydronephrosis at initial presentation. Five patients had bilaterally affected kidneys for a total of 60 diuresis renograms. Surgery was performed on 35 kidneys. We extracted 45 features based on curve shape and wavelet analysis from the drainage curves recorded after furosemide administration. The optimal features were selected as the combination that maximized the ROC AUC obtained from a linear support vector machine classifier trained to classify patients as with or without obstruction. Using these optimal features we performed leave 1 out cross validation to estimate the accuracy, sensitivity and specificity of our framework. Results were compared to those obtained using post-diuresis drainage half-time and the percent of clearance after 30 minutes. Our framework had 93% accuracy, including 91% sensitivity and 96% specificity, to predict surgical cases. This was a significant improvement over the same accuracy of 82%, including 71% sensitivity and 96% specificity obtained from half-time and 30-minute clearance using the optimal thresholds of 24.57 minutes and 55.77%, respectively. Our machine learning framework significantly improved the diagnostic accuracy of clinically significant hydronephrosis compared to half-time and 30-minute clearance. This aids in the clinical decision making process by offering a tool for earlier detection of severe cases and it has the potential to reduce the number of diuresis renograms required for diagnosis. Copyright © 2018 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

[History of ureteropelvic junction obstruction repair (pyeloplasty). From Trendelenburg (1886) to the present].

PubMed

Poulakis, V; Witzsch, U; Schultheiss, D; Rathert, P; Becht, E

2004-12-01

The first reconstructive procedure for ureteropelvic junction (UPJ) obstruction was performed by Trendelenburg in 1886. The important milestones in the reconstruction of UPJ are discussed and all available historical papers and reports since 1886 are reviewed. Kuster published the first successful dismembered pyeloplasty 5 years later, but his technique was prone to strictures. In 1892, the application of the Heineke-Mickulicz principle by Fenger resulted in bulking and kinking with obstruction. Plication of the renal pelvis, first introduced by Israel in 1896, was modified by Kelly in 1906. After the principle of the Finney pyloroplasty, von Lichtenberg designed his pyeloplasty in 1921, best suited to cases of high implantation of the ureter. Foley modified flap techniques, first introduced by Schwyzer in 1923 after the application of the Durante pyloroplasty principle, successfully to Y-V pyeloplasty in 1937. Culp and de-Weerd introduced the spiral flap in 1951. Scardino and Prince reported about the vertical flap in 1953. Patel published the extra-long spiral flap technique in 1982. In order to decrease the likelihood of stricture, Nesbit, in 1949, modified Kuster's procedure by utilizing an elliptic anastomosis. In the same year, Anderson and Hynes, published their technique. With the advent of endourology, several minimally invasive procedures were applied: antegrade or retrograde endopyelotomy, balloon dilation, and laparoscopic pyeloplasty. The concept of full-thickness incision of the narrow segment followed by prolonged stenting was first described in 1903 by Albarran and was popularized by Davis in 1943. Several basic principles must be applied in order to ensure successful repair: the resultant anastomosis should be widely patent, performed in a watertight fashion without tension. Endopyelotomy represents an alternative to open surgery.

Ureteral stone location at emergency room presentation with colic.

PubMed

Eisner, Brian H; Reese, Adam; Sheth, Sonali; Stoller, Marshall L

2009-07-01

It is thought that the 3 narrowest points of the ureter are the ureteropelvic junction, the point where the ureter crosses anterior to the iliac vessels and the ureterovesical junction. Textbooks describe these 3 sites as the most likely places for ureteral stones to lodge. We defined the stone position in the ureter when patients first present to the emergency department with colic. We retrospectively reviewed the records of 94 consecutive patients who presented to the emergency department with a chief complaint of colic and computerized tomography showing a single unilateral ureteral calculus. Axial, coronal and 3-dimensional reformatted computerized tomography scans were evaluated, and stone position and size (maximal axial and coronal diameters) were recorded, as were the position of the ureteropelvic junction, the iliac vessels (where the ureter crosses anterior to the iliac vessels) and the ureterovesical junction. Patients with a history of nephrolithiasis, shock wave lithotripsy, ureteroscopy or percutaneous nephrolithotripsy were excluded from study. Statistical analysis was performed using Student's t test and Pearson's correlation coefficient. At the time of emergency department presentation for colic ureteral stone position was the ureteropelvic junction in 10.6% cases, between the ureteropelvic junction and the iliac vessels in 23.4%, where the ureter crosses anterior to the iliac vessels in 1.1%, between the iliac vessels and the ureterovesical junction in 4.3% and at the ureterovesical junction in 60.6%. Proximal calculi had a greater axial diameter than distal calculi (mean 6.1 vs 4.0 mm) and a greater coronal diameter than distal calculi (6.8 vs 4.1 mm, each p <0.001). Axial and coronal diameters moderately correlated with stone position (r = -0.47 and -0.55, respectively, each p <0.001). Proximal ureteral stones were larger in axial and coronal diameter than distal ureteral stones. At emergency department presentation for colic most stones were at the ureterovesical junction and in the proximal ureter between the ureteropelvic junction and the iliac vessels. A few stones were at the ureteropelvic junction and only 1 lodged at the level where the ureter crosses anterior to the iliac vessels, despite the literature stating that these locations are 2 of the 3 most likely places for stones to become lodged.

Endoscopic placement of ureteral stents for treatment of congenital bilateral ureteral stenosis in a dog.

PubMed

Lam, Nathaniel K; Berent, Allyson C; Weisse, Chick W; Bryan, Christine; Mackin, Andrew J; Bagley, Demetrius H

2012-04-15

A 5-year-old 8.6-kg (18.9-lb) spayed female Pug was evaluated because of chronic hematuria and recurrent urinary tract infections. Excretory urography, ultrasonography, and excretory CT urography were performed. Results indicated that the dog had bilateral hydronephrosis and hydroureter and suspected proximal ureteral stenosis. Retrograde ureteropyelography confirmed the presence of stenosis at the ureteropelvic junction of each ureter, along with a large amount of endoluminal ureteral debris. Clinical findings suggested that the dog had a congenital bilateral anomaly of the upper urinary tract. The dog was anesthetized, and 2 double-pigtail ureteral stents were placed cystoscopically with fluoroscopic guidance for immediate relief of the ureteropelvic junction obstructions. Each stent extended from the left or right renal pelvis to the urinary bladder. The procedures and the patient's recovery from anesthesia were uncomplicated. Continuing improvements in severity of hydronephrosis, hydroureter, and dysuria were evident during routine follow-up examinations at 2, 4, 12, 16, and 45 weeks after stent placement. Over the subsequent 12 months, all clinical signs remained resolved other than a urinary tract infection that was successfully treated with antimicrobials. Ureteral stenosis should be considered as a differential diagnosis for hydronephrosis in dogs, particularly when urinary tract calculi or neoplasia is not present. Chronic hematuria and recurrent urinary tract infections can be associated with this condition. Placement of ureteral stents may be a successful treatment option for ameliorization of congenital ureteral obstructions.

Ultrasonic propulsion of kidney stones.

PubMed

May, Philip C; Bailey, Michael R; Harper, Jonathan D

2016-05-01

Ultrasonic propulsion is a novel technique that uses short bursts of focused ultrasonic pulses to reposition stones transcutaneously within the renal collecting system and ureter. The purpose of this review is to discuss the initial testing of effectiveness and safety, directions for refinement of technique and technology, and opinions on clinical application. Preclinical studies with a range of probes, interfaces, and outputs have demonstrated feasibility and consistent safety of ultrasonic propulsion with room for increased outputs and refinement toward specific applications. Ultrasonic propulsion was used painlessly and without adverse events to reposition stones in 14 of 15 human study participants without restrictions on patient size, stone size, or stone location. The initial feasibility study showed applicability in a range of clinically relevant situations, including facilitating passage of residual fragments following ureteroscopy or shock wave lithotripsy, moving a large stone at the ureteropelvic junction with relief of pain, and differentiating large stones from a collection of small fragments. Ultrasonic propulsion shows promise as an office-based system for transcutaneously repositioning kidney stones. Potential applications include facilitating expulsion of residual fragments following ureteroscopy or shock wave lithotripsy, repositioning stones prior to treatment, and repositioning obstructing ureteropelvic junction stones into the kidney to alleviate acute renal colic.

Pyeloplasty techniques using minimally invasive surgery (MIS) in pediatric patients.

PubMed

Turrà, Francesco; Escolino, Maria; Farina, Alessandra; Settimi, Alessandro; Esposito, Ciro; Varlet, François

2016-10-01

Hydronephrosis is the most common presentation of ureteropelvic junction (UPJ) obstruction. We reviewed literature, collecting data from Medline, to evaluate the current status of minimally invasive surgery (MIS) approach to pyeloplasty. Since the first pyeloplasty was described in 1939, several techniques has been applied to correct UPJ obstruction, but Anderson-Hynes dismembered pyeloplasty is established as the gold standard, to date also in MIS technique. According to literature several studies underline the safety and effectiveness of this approach for both trans- and retro-peritoneal routes, with a success rate between 81-100% and an operative time between 90-228 min. These studies have demonstrated the safety and efficacy of this procedure in the management of UPJ obstruction in children. Whether better the transperitoneal, than the retroperitoneal approach is still debated. A long learning curve is needed especially in suturing and knotting.

A practice pattern assessment of members of the Society of Pediatric Urology for evaluation and treatment of urinary tract dilation.

PubMed

Jackson, Jessica N; Zee, Rebecca S; Martin, Allison N; Corbett, Sean T; Herndon, C D Anthony

2017-12-01

Over the last decade the literature, including a multidisciplinary consensus statement, has supported a paradigm shift in management of urinary tract dilation, yet the impact on practice patterns has not been well documented. This study aims to elucidate specific practice patterns for treatment of prenatal unilateral urinary tract dilation and to assess surgical intervention patterns for ureteropelvic junction obstruction. An online survey was distributed to 234 pediatric urologists through the Society of Pediatric Urology. The survey was composed of five clinical case scenarios addressing evaluation and management of unilateral urinary tract dilation. The response rate was 71% (n = 168). Circumcision status, gender, and grade were significant factors in recommending prophylactic antibiotics for newborn urinary tract dilation. Prophylactic antibiotic use in the uncircumcised male and female was twice that of a circumcised male for grade 3 (Table). This difference was minimized for grade 4. Use of VCUG was high for circumcised males with grade 3 or 4 (Table). The choice of minimally invasive surgery for ureteropelvic junction repair increased with age from 19% for a 5-month-old, 49% for a 2-year-old, and 85% for a 10-year-old. Notably, 44% of respondents would observe a 10-year-old with intermittent obstruction. Retrograde pyelography was recommended in conjunction with repair in 65% of respondents. Antegrade stent placement was the most common choice (38-47%) for urinary diversion after pyeloplasty. Regarding postoperative imaging, only 5% opted for routine renal scan whereas most would perform renal ultrasound alone. Practice patterns seen for use of prophylactic antibiotics are in agreement with the literature, which promotes selective use in those at highest risk for urinary tract infections. Interestingly, use of aggressive screening was not concordant with this literature. Several studies have indicated an increased usage of robotic pyeloplasty; however, results indicate that minimally invasive surgery is not preferred in those younger than 6 months. Study limitations include use of clinical case scenarios as opposed to actual clinical practice. Practice patterns for prophylactic antibiotic use for neonatal urinary tract dilation are dependent on gender, circumcision status, and grade. The use of minimally invasive surgery for ureteropelvic junction repair increased with patient age, with 50% preferring this modality at 2 years. Copyright © 2017 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

Acoustic radiation force impulse (ARFI) elastography in the evaluation of renal parenchymal stiffness in patients with ureteropelvic junction obstruction.

PubMed

Habibi, Hatice Arioz; Cicek, Rumeysa Yasemin; Kandemirli, Sedat Giray; Ure, Emel; Ucar, Ayse Kalyoncu; Aslan, Mine; Caliskan, Salim; Adaletli, Ibrahim

2017-04-01

To investigate the role of acoustic radiation force impulse (ARFI) elastography in the detection of renal parenchymal damage in kidneys with and without ureteropelvic junction obstruction (UPJO). Twenty-five pediatric patients with a diagnosis of UPJO who underwent surgery and 15 pediatric patients with conservatively managed UPJO were prospectively evaluated with ARFI elastography. Sixteen healthy volunteers constituted the control group. Shear wave velocity (SWV) measurements in the upper, mid, and lower poles of the affected kidney were performed. SWV values of kidneys based on presence of UPJO and hydronephrosis grade were compared. The correlation of SWV values with residual renal function obtained from diethylenetriaminepentaacetic acid or mercaptoacetyltriglycine-3 renal scan was evaluated. Significantly, higher SWV values were found in control kidneys compared to kidneys affected by UPJO. The median SWVs were 2.82 (2.51-3.07) m/s for the control kidneys and 2.36 (2.09-2.53) m/s for the kidneys in the UPJO group (p < 0.001). When UPJO patients were grouped according to the grade of hydronephrosis, grade 0 hydronephrotic kidneys [2.35 (2.11-2.50) m/s] and grade 3-4 hydronephrotic kidneys [1.86 (1.96-2.25) m/s] had significantly lower SWV values compared to grade 1-2 hydronephrotic kidneys [2.62 (2.37-2.90) m/s] (p < 0.05). ARFI as a noninvasive, radiation-free procedure for evaluating parenchymal stiffness may prove useful in the diagnostic work-up and follow-up of children with UPJO-induced renal disease.

Useful technique for long-term urinary drainage by inlying ureteral stent. Six-year experience.

PubMed

Kearney, G P; Mahoney, E M; Brown, H P

1979-08-01

Endoscopically placed inlying ureteral stents have proved useful in the conservative management of patients with ureteral obstruction, urinary fistula, and malignancy and have obviated the need for operative intervention. In high-risk symptomatic patients with widespread malignancy, internal urinary diversion offers the opportunity for an improved quality of life without the surgical risk or potential morbidity of supravesical diversion. Potential candidates for this simple, safe, and effective technique include: those with postsurgical obstruction and/or fistula, retroperitoneal fibrosis, metastatic carcinoma, congenital ureteropelvic junction obstruction, as well as those with reversible obstruction from lymphoma and carcinoma of the prostate who are undergoing radiotherapy and/or chemotherapy. The focus of this report is on the technique we have found successful in providing us with stents that fit our individual patients. Readily available fabricated graduated ureteral catheter can be cut and shaped to particular measurements unlike prefabricated catheters. Minimal preparation time is demanded, and there is no need for extensive stocking of various catheter sizes.

Minimal invasive treatment of ureteropelvic junction obstruction in low volume pelvis: A comparative study of endopyelotomy and laparoscopic nondismembered pyeloplasty

PubMed Central

Singh, Pratipal; Jain, Paresh; Dharaskar, Anand; Mandhani, Anil; Dubey, Deepak; Kapoor, Rakesh; Kumar, Anant; Srivastava, Aneesh

2009-01-01

Objective: To evaluate the role of nondismembered laparoscopic pyeloplasty and percutaneous endopyelotomy for ureteropelvic junction obstruction (UPJO) with low volume renal pelvis. Material and Methods: Retrospective acquired data of 34 patients of laparoscopic nondismembered pyeloplasty was compared with 26 patients of UPJO with pelvic volume less than 50 ml undergoing antegrade endopyelotomy and analyzed for clinical parameters, operative outcomes and success of procedures. All patients were followed up clinically and with diuretic renogram at regular intervals. Results: Mean age, renal pelvic volume and preoperative glomerular filtration rate (GFR) was 25 years, 43.6 ml and 42.5 ml/min, respectively in endopyelotomy group and 21 years, 34.4 ml and 39.9 ml/min, respectively in laparoscopic pyeloplasty group. Mean operative time, postoperative analgesic requirement and mean hospital stay was 100min, 250 mg and 4 days, respectively in endopyelotomy group and 210 min, 300 mg and 4 days, respectively in laparoscopic pyeloplasty group. Only operative time was significantly different between two groups (P < 0.05). Mean follow-up was 36 and 39 months and success rates were 91.2% and 88.8% in laparoscopy and endopyelotomy group, respectively (P < 0.05). No significant complication was seen in endopyelotomy group while two patients had hematuria (one requiring blood transfusion) and three had increased drain output for more than 3 days in laparoscopy group. Conclusion: Percutaneous endopyelotomy is associated with significantly less operative time and postoperative complication rate and provides equivalent success in comparison to nondismembered laparoscopic pyeloplasty in patients with UPJO and low volume pelvis. It can be a preferred minimally invasive treatment modality for such patients. PMID:19468432

Improvement in Renal Function and Symptoms of Patients Treated with Laparoscopic Pyeloplasty for Ureteropelvic Junction Obstruction with Less Than 20% Split Renal Function.

PubMed

Nishi, Morihiro; Matsumoto, Kazumasa; Fujita, Tetsuo; Iwamura, Masatsugu

2016-11-01

To evaluate the efficacy of laparoscopic pyeloplasty (LPP) for lower functioning kidney, we investigated the outcome of this procedure for patients with ureteropelvic junction obstruction with decreased renal function, defined as less than 20% split renal function. Between October 1998 and June 2015, we performed transperitoneal dismembered LPP in 224 patients. Among them, 15 patients with less than 20% split renal function were included in this study. Patient characteristics, perioperative split renal functions, complications, and surgical outcomes were retrospectively investigated. Fourteen of 15 patients had preoperative symptoms, including flank pain in 13 patients and gross hematuria in 1 patient. Preoperative 99mTc-mercaptoacetyltriglycine (MAG3) renogram revealed no response to diuretic injection and median split renal function was 16.5%. Median operative time and blood loss were 170 minutes and 20 mL, respectively. There were no complications during the perioperative period. Postoperative MAG3 renogram at 6 and 12 months after the operation revealed significantly increased split renal function (median: 23.8% and 23.7%, p = 0.001 and 0.008, respectively) and response to diuretic injection in all patients. Preoperative symptoms disappeared and no recurrence was seen during the follow-up period for all patients except for one who experienced flank pain again 4 months after the surgery. He subsequently underwent open pyeloplasty, and flank pain disappeared soon after. LPP for patients with low split renal function and flank pain significantly improved symptoms and split renal functions. Although the long-term clinical effects of LPP are unknown, we recommend performing LPP before considering nephrectomy for patients with lower functioning kidney.

Antenatal Hydronephrosis: Differential Diagnosis, Evaluation, and Treatment Options

PubMed Central

Herndon, C.D. Anthony

2006-01-01

The diagnosis, evaluation and management of antenatal hydronephrosis has undergone a two stage paradigm shift since the advent of prenatal ultrasonography in the early 1980s. Initially the identification of a large number of asymptomatic infants appeared to afford the surgeon the opportunity for preemptive intervention. However, it has now become apparent that antenatal hydronephrosis (AH) is far more difficult to interpret thanoriginally perceived. The initial enthusiasm for surgery has now been replaced by a much more conservative approach to ureteropelvic junction(UPJ) obstruction, multi-cystic dysplastic kidney(MCDK), vesicoureteral reflux and the non-refluxing megaureter. This review will highlight the postnatal evaluation of AH and include an overview of the Society for Fetal Urology grading system for hydronephrosis. The differential diagnosis and treatment options for UPJ obstruction, vesicoureteral reflux, MCDK, duplication anomalies, megaureter, and posterior urethral valves will be discussed. PMID:17619702

Huge maternal hydronephrosis: a rare complication in pregnancy.

PubMed

Peng, Hsiu-Huei; Wang, Chin-Jung; Yen, Chih-Feng; Chou, Chien-Chung; Lee, Chyi-Long

2003-06-10

A huge maternal hydronephrosis is uncommon in pregnancy and might be mistaken as a pelvic mass. A 21-year-old primigravida was noted at 25th week of gestation to have a visible bulging mass on her left flank. The mass was originally mistaken as a large ovarian cyst but later proved to be a huge hydronephrosis. Retrograde insertion of ureteroscope and a ureteric stent failed, so we performed repeated ultrasound-guided needle aspiration to decompress the huge hydronephrosis, which enabled the patient to proceed to a successful term vaginal delivery. Nephrectomy was performed after delivery and proved the diagnosis of congenital ureteropelvic junction obstruction.

Complications of retrograde balloon cautery endopyelotomy.

PubMed

Schwartz, B F; Stoller, M L

1999-11-01

Adult ureteropelvic junction obstruction is increasingly managed with endoscopic techniques. Retrograde balloon cautery endopyelotomy is quick, requires minimal hospital stay and allows most patients a rapid return to work. The complication rate of retrograde balloon cautery endopyelotomy ranges from 13 to 34%, with vascular injury in 0 to 16% of patients. We report 5 uncommon complications, including 4 vascular injuries, that clinicians should be familiar with when using this technique. We reviewed 52 retrograde endoscopic endopyelotomy procedures performed during a 5-year period. There were 5 uncommon complications. Accessory lower pole renal artery injuries occurred in 3 patients, 1 of whom presented 12 days after endopyelotomy. Embolization was successfully performed in all 3 cases and none had subsequent hypertension. In 1 case a right ovarian vein laceration was not evident on preoperative or postoperative angiography. Emergency post-embolization abdominal exploration revealed a 2 mm. injury to the right ovarian vein before entering the right renal vein close to the ureteropelvic junction incision. Nephrectomy and ovarian vein ligature were curative. In 1 case the electrocautery wire broke intracorporeally after firing, resulting in a bobby pin-like configuration. Successful removal was accomplished by twisting the catheter and wrapping the wire around the tip, enabling atraumatic removal. Retrograde balloon cautery endopyelotomy is an emerging technology with potential adverse outcomes. The complications we noted are complex and potentially life threatening. Awareness of these complications may help avoid poor outcomes and expedite appropriate treatment.

Prediction of Clinical Outcomes in Prenatal Hydronephrosis: Importance of Gravity Assisted Drainage.

PubMed

Sussman, Rachael D; Blum, Emily S; Sprague, Bruce M; Majd, Massoud; Rushton, H Gil; Pohl, Hans G

2017-03-01

In infants with SFU (Society for Fetal Urology) grade 3-4 congenital hydronephrosis, 99m Tc-mercaptoacetyltriglycine diuretic renography assesses differential function and drainage half-time. We routinely also include the percent of radiotracer drained after 30 minutes of diuresis as well as after 15 minutes with the patient in the upright position. We investigated whether any 1 or more of these parameters on initial diuretic renography predicts persistent or worsening drainage parameters. Infants 6 months or younger with grade 3-4 congenital hydronephrosis who presented between January 2009 and December 2014 were identified from billing data and included in analysis if they underwent at least 1 baseline diuretic renography. Those with structural anomalies were excluded from study. Baseline and followup differential function, diuresis half-time, clearance at 30 minutes and clearance with the patient upright were abstracted and comparisons were made between those with initially indeterminate diuresis half-time who underwent pyeloplasty vs those showing spontaneous improvement. A total of 74 patients (82 renal units) with presumed ureteropelvic junction obstruction met inclusion/exclusion criteria. All 10 renal units with initial diuresis half-time less than 5 minutes resolved spontaneously and all 25 renal units with initial diuresis half-time greater than 75 minutes underwent pyeloplasty. Therefore, we defined the indeterminate group as the 47 renal units with initial half-time between 5 and 75 minutes. Of those 47 renal units with indeterminate initial diuresis half-time 23 (47%) underwent pyeloplasty and 25 (53%) resolved spontaneously. Indications for pyeloplasty included worsening in 17 cases, persistent obstruction in 4 and urinary tract infection in 1. Among renal units with indeterminate drainage clearance while upright and clearance at 30 minutes were the only variables that differed significantly between surgical cases and those that resolved spontaneously. Radiotracer clearance with the patient upright and clearance at 30 minutes are more predictive of surgical management than diuresis half-time or differential function for renal units with indeterminate drainage. They should be included in the standard assessment of ureteropelvic junction obstruction. Copyright © 2017 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

The morphology and treatment of coexisting ureteropelvic junction obstruction in lower moiety of duplex kidney.

PubMed

Liu, Wei; Zhang, Liujuan; Ma, Rui; Wu, Rongde

2016-10-01

Duplex kidney is a common congenital anomaly of the urinary tract, while ureteropelvic junction obstruction (UPJO) in lower unit of duplex kidney is rare. Surgical treatment can be challenging in such cases. The aim was to report our experience in managements of UPJO in lower moiety of duplex kidney. Among the pediatric patients with duplex system from 2007 to 2013, 7 children were diagnosed with UPJO in lower moiety. Their medical records were retrospectively analyzed, mainly focused on anatomic aspects and operation details. The lower pole UPJO associated with incomplete duplex systems were identified in 6 patients on the left side and 1 on the right side. Median patient age at surgery was 11 months (range 6-84 months). Prenatal hydronephrosis was detected in 4 patients, and 3 had intermittent abdominal pain. Hydronephrosis, thin parenchyma and presence of UPJO in lower moiety could be shown on computed tomography urogram (CTU). The ureters were fused in a "Y" shape without any dilation. Based on the length between UPJO to the confluence in retrograde ureteropyelography, patients were classified into group 1 (5 cases,≤3 cm) and group 2 (2 cases, >3 cm). In group 1, surgical procedure involved end-to-side pyeloureterostomy of the lower pelvis to the ureteral confluence in 4 cases and laparoscopic pyeloureterostomy in one case. The two patients in group 2 underwent laparoscopic pyeloplasty of lower moiety. In all of these patients hydronephrosis gradually improved and no complications were detected during follow-up. UPJO in a duplex kidney requires careful evaluation and treatment should be individualized. Ureteropyeloanastomosis is a feasible treatment for duplex kidneys associated to a functioning lower moiety with UPJO. With the technical improvements in laparoscopic pyeloplasty, this procedure can be performed using laparoscopy. Copyright © 2016 IJS Publishing Group Ltd. Published by Elsevier Ltd. All rights reserved.

Retroperitoneal and transperitoneal robot-assisted pyeloplasty in adults: techniques and results.

PubMed

Cestari, Andrea; Buffi, Nicolò Maria; Lista, Giuliana; Sangalli, Mattia; Scapaticci, Emanuele; Fabbri, Fabio; Lazzeri, Massimo; Rigatti, Patrizio; Guazzoni, Giorgio

2010-11-01

The surgical management of ureteropelvic junction obstruction (UPJO) has dramatically evolved over the past 20 yr due to the development of new technology. Our aim was to report the feasibility and efficacy of robot-assisted pyeloplasty (RAP) performed by either the retroperitoneal or the transperitoneal approach. A stage 2 investigative study was conducted including development (stage 2a) and exploration (stage 2b) of transperitoneal and retroperitoneal RAP performed in 55 patients at an urban tertiary university department of urology. Retroperitoneal RAP was performed with the patient in full flank position using a 12-mm Hasson-style optical port at the tip of the 12th rib, plus two operative 8-mm robotic trocars and an assistant 5-mm port. The stenotic ureteropelvic junction was excised, the ureter was spatulated, and a dismembered pyeloplasty was performed in all cases. Transperitoneal RAP was performed with the patients in the 60° flank position. The optical port is in the umbilical area, plus two 8-mm operative robotic ports and one 5-mm assistant port. The pyeloplasty technique is similar to the retroperitoneoscopic approach. In both groups, the stent can be positioned in an anterograde or retrograde fashion. Success consisted of no evidence of obstruction on computed tomography urography or mercaptoacetyltriglycine-3 diuretic renal scan, no postoperative symptoms, and no further treatment. Thirty-six patients underwent retroperitoneoscopic RAP and 19 transperitoneal RAP for UPJO. All the procedures were completed with robotic assistance. The overall objective success (measured by diuretic renal scan and/or imaging techniques) was 96% with two cases of recurrence (both in the retroperitoneal group). The main limitation was the short follow-up, although all patients reached at least a 6-mo follow-up. RAP performed either retroperitoneally or transperitoneally was revealed as a feasible and reproducible surgical option for the treatment of UPJO, offering a subjective optimal plasty reconfiguration at short follow-up. Copyright © 2010 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Role of acellular collagen matrix surgisis in the endoscopic management of ureteropelvic junction obstruction.

PubMed

Yohannes, Paulos; Rotariu, Paul; Liatsikos, Evangelos; Malik, Aftab; Alexianu, Mihai; Pinkasov, David; Morgenstern, Nora; Lee, Benjamin R; Smith, Arthur D

2002-10-01

To investigate the role of acellular collagen matrix (Surgisis during endopyelotomy. Nine female pigs (25-35 kg) were enrolled in our protocol. The pigs were categorized as follows. Group I (N = 3) had endopyelotomy + insertion of SIS, Group II (N = 3) creation of UPJ stricture + endopyelotomy + insertion of SIS, and Group III (N = 3) Davis intubated ureterotomy using SIS. The contralateral side served as a control for each group (one pig in each group). In three pigs (two in Group III and one in Group II), Surgisis was treated with India ink prior to insertion at the endopyelotomy site. An endopyelotomy stent (14/8 F x 24 cm) was used to stent the ureteropelvic junction (UPJ) for 4 weeks. Four weeks after the stent was removed, laparoscopic nephroureterectomy was performed, and the animals were euthanized. Histopathologic analysis of the Surgisis-regenerated segment of the UPJ was performed using hematoxylin and eosin, reticular (collagen), smooth muscle actin, and S-100 (nerve) stains. All animals tolerated the procedure. The mean operative time was 162 minutes. One pig (Group II) developed pyonephrosis; one pig (Group III) developed significant ascites and was sacrificed 2 week before the end of the experiment. Histopathologic analysis showed complete epithelializaton at 8 weeks. Reticular stain demonstrated abundant collagen matrix in the submucosa. Smooth muscle staining revealed myofibroblastic proliferation within the SIS-regenerated tissue adjacent to disorganized smooth muscle cells. India ink-stained SIS-regenerated tissue did not show smooth muscle cells. The S-100 stain did not demonstrate neurons at 8 weeks; however, in three pigs, peristaltic activity was noted across the UPJ. The use of acellular collagen matrix in the endoscopic management of UPJ obstruction is a promising technique. The abundance of myofibroblasts and absence of abundant smooth muscle regeneration indicates a need to investigate the role of growth factors in SIS regeneration of host tissue.

Prospective analysis of completely stentless robot-assisted pyeloplasty in children.

PubMed

Casale, Pasquale; Lambert, Sarah

2010-01-01

Robot-assisted pyeloplasty (RAP) is emerging as an effective tool for treatment of ureteropelvic junction obstruction (UPJO) in the pediatric population. Typically stents are utilized for RAP and removed four weeks after the procedure. We present our prospective experience with stentless RAP. Twenty children between the ages of 12 and 113 months (mean age 56 months) underwent transperitoneal RAP for UPJO utilizing the DaVinci surgical system. Outcome measures included operative time, length of hospital stay, and resolution of obstruction by ultrasonography, magnetic resonance urography (MRU), and/or diuretic radionuclide imaging (DRI). All patients successfully underwent robot-assisted laparoscopic pyeloplasty without conversion to pure laparoscopy or open procedure. Mean operative time was 124.7 min with a mean console time of 82.3 min. The mean hospital stay was 18 h. Of the 20 patients, 13/20 (65%) had resolution or improvement in the degree of hydronephrosis. The other patients had no evidence of obstruction based upon follow-up MRU or DRI. Stentless RAP is a safe and effective option for surgical treatment of UPJO. A larger prospective long-term cohort is needed to confirm the safety and efficacy of the stentless approach.

Dismembered Pyeloplasty in Infants 6 Months Old or Younger With and Without External Trans-anastomotic Nephrostent: A Prospective Randomized Study.

PubMed

Nasser, Farouk M; Shouman, Ahmed M; ElSheemy, Mohammed S; Lotfi, Mohammed A; Aboulela, Waseem; El Ghoneimy, Mohamed; Abdelwahhab, Mohammad; Shoukry, Ahmed I; Ghoneima, Waleed; Morsi, Hany; Badawy, Hesham

2017-03-01

To compare the outcome of dismembered pyeloplasty in infants with and without external nephro-ureteric stent (ENUS) for treatment of congenital ureteropelvic junction obstruction. This is a parallel, randomized comparative study between October 2013 and September 2014. Thirty infants ≤6 months old with ureteropelvic junction obstruction indicated for dismembered pyeloplasty were randomly assigned (block randomization, closed envelope method) into two groups: group A (stentless) and group B (ENUS). Infants with solitary kidney, gross pyuria, huge pelvis, vesicoureteric reflux, or other renal anomalies were excluded. Operative data, complications, and ultrasonographic and nuclear scintigraphy criteria were compared after at least 18 months of follow-up using Student t, Mann-Whitney U, Kruskal-Wallis, chi-square, and Fisher exact tests when appropriate. Occurrence of urinary leakage was the primary outcome. Included patients completed the study with intention-to-treat analysis. All children had normal renal function. The mean operative time was 85.3 ± 6.3 (60-90) minutes in group A and 92.6 ± 15.3 (70-120) minutes in group B (P = .2). Although there was a significant postoperative improvement in each group in split renal function and anterior-posterior renal pelvis diameter, there was no significant difference between both groups. The mean hospital stay for group A and group B was 5.9 ± 2 (4-10) days versus 3.5 ± 0.8 (2-5) days, respectively (P < .001). Postoperative urinary leakage was reported only in group A (40%). All complications were managed by double J insertion. Auxiliary interventions were higher in group A. The overall success rate was 93.4%. Redo pyeloplasty was performed in one case in each group. ENUS significantly reduces hospital stay and complications. It saves the infant hazards of auxiliary interventions under general anesthesia for management of leakage or double J removal if placed at time of pyeloplasty. Copyright © 2016 Elsevier Inc. All rights reserved.

Robot-assisted laparoscopic pyeloplasty: minimum 1-year follow-up

NASA Astrophysics Data System (ADS)

Patel, Vipul; Thaly, Rahul; Shah, Ketul

2007-02-01

Objectives: To evaluate the feasibility and efficacy of robotic-assisted laparoscopic pyeloplasty. Laparoscopic pyeloplasty has been shown to have a success rate comparable to that of the open surgical approach. However, the steep learning curve has hindered its acceptance into mainstream urologic practice. The introduction of robotic assistance provides advantages that have the potential to facilitate precise dissection and intracorporeal suturing. Methods: A total of 50 patients underwent robotic-assisted laparoscopic dismembered pyeloplasty. A four-trocar technique was used. Most patients were discharged home on day 1, with stent removal at 3 weeks. Patency of the ureteropelvic junction was assessed in all patients with mercaptotriglycylglycine Lasix renograms at 1, 3, 6, 9, and 12 months, then every 6 months for 1 year, and then yearly. Results: Each patient underwent a successful procedure without open conversion or transfusion. The average estimated blood loss was 40 ml. The operative time averaged 122 minutes (range 60 to 330) overall. Crossing vessels were present in 30% of the patients and were preserved in all cases. The time for the anastomosis averaged 20 minutes (range 10 to 100). Intraoperatively, no complications occurred. Postoperatively, the average hospital stay was 1.1 days. The stents were removed at an average of 20 days (range 14 to 28) postoperatively. The average follow-up was 11.7 months; at the last follow-up visit, each patient was doing well. Of the 50 patients, 48 underwent one or more renograms, demonstrating stable renal function, improved drainage, and no evidence of recurrent obstruction. Conclusions: Robotic-assisted laparoscopic pyeloplasty is a feasible technique for ureteropelvic junction reconstruction. The procedure provides a minimally invasive alternative with good short-term results.

Complications of acucise endopyelotomy.

PubMed

Kim, F J; Herrell, S D; Jahoda, A E; Albala, D M

1998-10-01

Endoscopic management of ureteropelvic junction (UPJ) obstruction has a success rate of 80% to 86%. We have been performing a ureteral cutting balloon procedure under fluoroscopic control (Acucise endopyelotomy) for UPJ obstruction at Loyola University Medical Center since 1991. The overall success rate in 77 patients was 78%. All patients had a preoperative intravenous urogram or a retrograde pyelogram, but none had vascular imaging studies. Acucise endopyelotomy consisted of a posterolateral incision of the UPJ and placement of an endopyelotomy or double-J stent. Foley catheter placement at the end of the procedure demonstrated significant gross hematuria in three patients (4%). All three remained hemodynamically stable but with significant drops in postprocedure hemoglobin levels, which necessitated blood transfusion. Aggressive management included angiographic studies and embolization of lower-pole branching arteries in two patients (3%). One patient stopped bleeding after being given two units of blood. None of the patients required an open exploratory procedure. Although the risk of vascular injury is low with Acucise endopyelotomy, prolonged postoperative gross hematuria does mandate investigation and observation. Angiographic embolization appears to be the therapeutic modality of choice for patients with hemorrhagic complications after an Acucise endopyelotomy.

Hydronephrosis: Comparison of extrinsic vessel versus intrinsic ureteropelvic junction obstruction groups and a plea against the vascular hitch procedure.

PubMed

Menon, Prema; Rao, Katragadda L N; Sodhi, Kushaljit S; Bhattacharya, A; Saxena, Akshay K; Mittal, Bhagwant R

2015-04-01

Pediatric ureteropelvic junction obstruction (UPJO) due to an extrinsic crossing vessel (CV) is rare and often remains undiagnosed preoperatively. Vascular hitch procedures are often performed as associated intrinsic obstruction is not expected. We compared data and intravenous urography (IVU) findings of patients with aberrant CV versus those with intrinsic UPJO, all undergoing open dismembered pyeloplasty. Is accurate pre-operative diagnosis of aberrant CV causing extrinsic UPJO possible? To assess differences in the demographic, clinical, radiological, intra-operative features and postoperative improvement after pyeloplasty between patients with a CV and those with only intrinsic UPJO. Prospective study of all children below 12 years with UPJO presenting to a tertiary referral centre and who underwent open Anderson - Hynes dismembered pyeloplasty between 2003 and 2013 was conducted. Pre-operative investigations included serial ultrasonography, renal dynamic [ethylene di-cysteine (EC)] scan and IVU. These were repeated 3 months after pyeloplasty. Pre-operative IVUs of children with CV were compared with the IVUs of an equal number of similar aged children, randomly selected from the intrinsic obstruction group. Pyeloplasty was performed in 643 children during the study period. Data of 33 children with aberrant CVs (mean age 6.99 years) were compared with the remaining 610 children (mean age 3.27 years) with only intrinsic obstruction. Highly significant associations of those with CV included age above 2 years, female gender, associated anomalies, abdominal pain in those above 2 years and poor preoperative function on IVU. Specific IVU features which were statistically highly significant in favor of presence of CV were small, intrarenal and globular flat bottomed pelvis. (Figure) Calyceal dilatation was also more prominent in the CV group. A funnel shaped, extrarenal pelvis was highly significant in favor of intrinsic obstruction. There was associated intrinsic obstruction in addition to CV obstruction in 8 children. All children symptomatically improved after pyeloplasty and did well on long term follow up. The majority showed improvement or stabilization of function on EC scan. With the advent of antenatal ultrasonography, most children with UPJO are detected early. Children with CV tend to present later. This is often detected during surgery. Color Doppler is useful but is operator dependant and not performed routinely. In this study, IVU showed the presence of obstruction and loss of function unlike color Doppler, but also revealed specific diagnostic features not previously reported in literature. This can help in accurate preoperative prediction and avoid endopyelotomy, or a dorsal lumbotomy/retroperitoneal approach. Renal function in CVs is expected to be good as the obstruction is thought to be intermittent. However, we noted delayed contrast uptake on IVU in 60.6% and differential renal function on EC scan below 40% in 17 patients (56.6%). These indicate the effect of the obstruction on the renal parenchyma and the importance of early detection. Higher association with other anomalies and higher incidence in females has also not been emphasized in the literature so far. We noted associated intrinsic obstruction in 24.24% patients which is highly significant. This category of patients is likely to be missed and inappropriately treated if a "vascular hitch procedure" is performed. None of our patients had postoperative complications. Characteristic features were seen on IVU helping in preoperative diagnosis which can be extrapolated to magnetic resonance urography. There is a higher association of CV in age above 2 years, females, associated congenital anomalies, delayed uptake on IVU and differential renal function below 40% compared to intrinsic obstruction. Associated intrinsic obstruction in 24% with no postoperative complications indicates the superiority of dismembered pyeloplasty over vasculopexy procedures. Copyright © 2015 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

Robot-assisted, single-site, dismembered pyeloplasty for ureteropelvic junction obstruction with the new da Vinci platform: a stage 2a study.

PubMed

Buffi, Nicolò Maria; Lughezzani, Giovanni; Fossati, Nicola; Lazzeri, Massimo; Guazzoni, Giorgio; Lista, Giuliana; Larcher, Alessandro; Abrate, Alberto; Fiori, Cristian; Cestari, Andrea; Porpiglia, Francesco

2015-01-01

Laparoendoscopic single-site surgery (LESS) has gained popularity in urology over the last few years. To report a stage 2a study of robot-assisted single-site (R-LESS) pyeloplasty for ureteropelvic junction obstruction (UPJO). This study is an investigative pilot study of 30 consecutive cases of R-LESS pyeloplasty performed at two participating institutions between July 2011 and September 2013. Dismembered R-LESS pyeloplasty was performed at two surgical centers. Feasibility (conversion rate), safety (complication rate and Clavien-Dindo classification), efficacy (clinical outcome) of the procedure were assessed. The median patient age was 37 yr (range: 19-65 yr) and median body mass index was 23 kg/m(2) (range: 19-29 kg/m(2)). The median operative time was 160 min (range: 101-300 min), the median postoperative stay was 5 d (range: 3-13 d), and the median time to catheter removal was 3 d (range: 2-10). Two cases required conversion, the first one to standard laparoscopic technique and the second one to standard robotic technique. No intraoperative complications were reported. In three cases, an additional 5-mm trocar was needed. The postoperative complications rate was 26% (n=8). Most of them were grade 1 complications (n=4; 13%), followed by grade 2 (n=3; 10%) and grade 3 (n=1; 3.3%) complications, according to the Clavien-Dindo classification. One patient needed a surgical reintervention with standard robotic technique 3 d after surgery for urinary leakage. The overall success rate, considered as the resolution of symptoms and the absence of functional impairment at postoperative imaging, was 93.3% (n=28) at a median follow-up of 13 mo (range: 3-21 mo). The main limitations of this study are the limited number of patients included and the short-term follow-up. Single-site robotic pyeloplasty is a feasible technique in selected patients, with good cosmetic results and excellent short-term clinical outcomes. Prospective studies are needed to further assess its role for the treatment of UPJO. Single-site robot-assisted pyeloplasty is a feasible technique with good cosmetic results and excellent short-term clinical outcomes. Copyright © 2014. Published by Elsevier B.V.

Common Pediatric Urological Disorders

PubMed Central

Robson, Wm. Lane M.; Leung, Alexander K.C.; Boag, Graham S.

1991-01-01

The clinical and radiological presentations of 12 pediatric urological disorders are described. The described disorders include pyelonephritis, vesicoureteral reflux, ureteropelvic obstruction, ureterovesical obstruction, ectopic ureterocele, posterior urethral valves, multicystic dysplastic kidney, polycystic kidney disease, ectopic kidney, staghorn calculi, urethral diverticulum, and urethral meatal stenosis. ImagesFigure 1-2Figure 3Figure 3Figure 4Figure 5Figure 6-7Figure 8-9Figure 10Figure 11-12 PMID:21229068

Recurrent severe abdominal pain in the pediatric patient.

PubMed

Homme, James L; Foster, Ashley A

2014-05-01

Ureteropelvic junction obstruction (UPJO) is a blockage occurring at the junction of the ureter and the renal pelvis. Pediatric patients with UPJO pose a diagnostic challenge when they present to the emergency department (ED) with severe recurrent abdominal pain if there is not a level of suspicion for this condition. Our aim was to review presentation of UPJO to the ED, methods of diagnosis, and treatment of this common but often overlooked condition. We report on 2 patients, a 9-year-old and 3-year-old, who had multiple presentations to health care providers and the ED with intermittent and recurrent abdominal pain. Subsequent testing, including ultrasound (US) and computed tomography (CT) with diuretic-recreated symptoms, revealed UPJO. Open pyeloplasty was performed, resulting in complete resolution of symptoms. UPJO is an important diagnosis to consider when patients present to the ED with recurrent abdominal pain. US can be helpful in suspecting the diagnosis, but often CT, magnetic resonance urography, or diuretic scintigraphy is required for confirmation. Diuretics can be used to aid diagnostic testing by reproducing abdominal pain at the time of imaging. Referral to a urologist for open pyeloplasty is definitive treatment for this condition. Copyright © 2014 Elsevier Inc. All rights reserved.

[Giant idiopathic hydronephrosis: toward a two-step therapeutic approach].

PubMed

Boudhaye, Taher Ismail; Sidimalek, Mohamed; Jdoud, Cheikhani

2017-01-01

Giant hydronephrosis is rare. It is usually caused by ureteropelvic junction syndrome. We here report the unusual case of a patient hospitalized with giant hydronephrosis associated with impaired general condition. Diagnosis was based on CT scan. The patient underwent deferred nephrectomy after percutaneous drainage.

The role of dynamic renal scintigraphy on clinical decision making in hydronephrotic children.

PubMed

Çamlar, Seçil Arslansoyu; Deveci, Nazlı; Soylu, Alper; Türkmen, Mehmet Atilla; Özmen, Derya; Çapakaya, Gamze; Kavukçu, Salih

2017-01-01

Hydronephrosis may be related to an obstructive cause, ureteropelvic/uretero-vesical junction obstruction or nonobstructive [vesicoureteral reflux (VUR)]. When an obstructive pathology is considered, dynamic renal scintigraphy may help to predict whether it is a true obstruction or not. In this study, we aimed to determine the contribution of dynamic renal scintigraphy with [99] mTc-MAG-3 to the clinical decision-making for surgery in hydronephrotic children. Files of the patients evaluated by MAG-3 scintigraphy for antenatal (AH)/postnatal (PH) hydronephrosis between 1992 and 2014 were reviewed. Gender, age, hydronephrosis (HN) grade by ultrasound (US), presence of VUR, MAG-3 result (obstructive vs. nonobstructive), ultimate diagnosis, and need for surgery were assessed. Cases with double collecting system and neurogenic bladder were excluded from the study. All of the patients had normal serum creatinine and eGFR. There were a total of 178 patients with 218 hydronephrotic renal units (mean age 34.7 ± 52.7 months; male/ female = 121/57, AH of 62%). MAG-3 was nonobstructive in 134 and obstructive in 84 hydronephrotic renal units. MAG-3 was obstructive in 47 of 121 (39%) males and 30 of 57 (53%) females (P = 0.058, odds ratio (OR) for obstruction was 1.9 for girls). MAG-3 was obstructive in 47 of 135 (35%) units with AH and 37 of 83 (45%) units with PH (P = 0.137). In 81 units with the society of fetal urology-4 HN by US, MAG-3 was obstructive in 55 (68%), and surgery was required in 52 of 55 (95%). Surgery was required for only two (7%) of the remaining 26 units with nonobstructive dilatation (P <0.001, sensitivity 96%, specificity 89%, OR 208). Antero-posterior diameter >16.5 mm was the best cutoff level for predicting obstruction by MAG-3 (sensitivity 75.2%; specificity 71%; OR 3.8). MAG-3 significantly affects clinical decision for surgery in HN. Hydronephrotic girls have more risk in terms of true obstruction. Combining MAG-3 with US improves the discrimination of true obstruction during follow-up.

Incidence and implications of silent hydronephrosis following percutaneous nephrolithotomy
.

PubMed

Dagrosa, Lawrence; Moses, Rachel; Pais, Vernon M

2017-01-01

While routine renal imaging following ureteroscopy for urinary calculi has been recommended to screen for asymptomatic "silent" obstruction, the rate of silent obstruction following percutaneous nephrolithotomy (PCNL) remains poorly defined, and no consensus recommendations exist on routine postoperative imaging. At our institution, we sought to assess the incidence of silent hydronephrosis (SH), as a screen for obstruction, following PCNL. The records of all 162 patients who met study inclusion criteria were reviewed. Of this group, 112 patients presented for their scheduled renal ultrasonography 4 - 6 weeks following stent removal to screen for SH. Asymptomatic patients found to have ultrasonographic evidence of hydronephrosis were further analyzed. SH was noted in 16% (18/112) of patients. Two required subsequent ureteroscopic stone extraction (1.8%), one of which also underwent endoureterotomy for a ureteral stricture. Four patients (22%) had stable hydronephrosis and declined functional imaging, 2 patients (11%) had a known partial ureteropelvic junction obstruction and declined intervention. SH resolved spontaneously in 50% (9/18) with a mean time to resolution of 6.3 months. There was no difference in stone complexity based on Guy's stone score between groups, 2.8 (± 0.92) vs. 2.4 (± 1.03), p = 0.34. Although not statistically significant, patients with SH were more likely to have had residual stone fragments postoperatively, 39% (7/18) vs. 19% (18/94), p = 0.067. SH following, PCNL was identified in 16% of this screened population, with the majority requiring no intervention. However, SH may be attributed to residual stone or stricture, which may have been otherwise unrecognized in up to 2% of patients undergoing PCNL. Consideration should be given for routine postoperative ultrasound to screen for silent obstruction following PCNL.
.

Lower urinary tract development and disease

PubMed Central

Rasouly, Hila Milo; Lu, Weining

2013-01-01

Congenital Anomalies of the Lower Urinary Tract (CALUT) are a family of birth defects of the ureter, the bladder and the urethra. CALUT includes ureteral anomalies such as congenital abnormalities of the ureteropelvic junction (UPJ) and ureterovesical junction (UVJ), and birth defects of the bladder and the urethra such as bladder-exstrophy-epispadias complex (BEEC), prune belly syndrome (PBS), and posterior urethral valves (PUV). CALUT is one of the most common birth defects and is often associated with antenatal hydronephrosis, vesicoureteral reflux (VUR), urinary tract obstruction, urinary tract infections (UTI), chronic kidney disease and renal failure in children. Here, we discuss the current genetic and molecular knowledge about lower urinary tract development and genetic basis of CALUT in both human and mouse models. We provide an overview of the developmental processes leading to the formation of the ureter, bladder, and urethra, and different genes and signaling pathways controlling these developmental processes. Human genetic disorders that affect the ureter, bladder and urethra and associated gene mutations are also presented. As we are entering the post-genomic era of personalized medicine, information in this article may provide useful interpretation for the genetic and genomic test results collected from patients with lower urinary tract birth defects. With evidence-based interpretations, clinicians may provide more effective personalized therapies to patients and genetic counseling for their families. PMID:23408557

A capillary electrophoresis coupled to mass spectrometry pipeline for long term comparable assessment of the urinary metabolome.

PubMed

Boizard, Franck; Brunchault, Valérie; Moulos, Panagiotis; Breuil, Benjamin; Klein, Julie; Lounis, Nadia; Caubet, Cécile; Tellier, Stéphanie; Bascands, Jean-Loup; Decramer, Stéphane; Schanstra, Joost P; Buffin-Meyer, Bénédicte

2016-10-03

Although capillary electrophoresis coupled to mass spectrometry (CE-MS) has potential application in the field of metabolite profiling, very few studies actually used CE-MS to identify clinically useful body fluid metabolites. Here we present an optimized CE-MS setup and analysis pipeline to reproducibly explore the metabolite content of urine. We show that the use of a beveled tip capillary improves the sensitivity of detection over a flat tip. We also present a novel normalization procedure based on the use of endogenous stable urinary metabolites identified in the combined metabolome of 75 different urine samples from healthy and diseased individuals. This method allows a highly reproducible comparison of the same sample analyzed nearly 130 times over a range of 4 years. To demonstrate the use of this pipeline in clinical research we compared the urinary metabolome of 34 newborns with ureteropelvic junction (UPJ) obstruction and 15 healthy newborns. We identified 32 features with differential urinary abundance. Combination of the 32 compounds in a SVM classifier predicted with 76% sensitivity and 86% specificity UPJ obstruction in a separate validation cohort of 24 individuals. Thus, this study demonstrates the feasibility to use CE-MS as a tool for the identification of clinically relevant urinary metabolites.

Detection of crossing vessels in pediatric ureteropelvic junction obstruction: Clinical patterns and imaging findings.

PubMed

Weiss, Dana A; Kadakia, Sagar; Kurzweil, Rebecca; Srinivasan, Arun K; Darge, Kassa; Shukla, Aseem R

2015-08-01

Pediatric ureteropelvic junction obstruction (UPJO) is caused by congenital intrinsic narrowing and/or a lower pole-crossing renal artery. When a crossing renal vessel (CRV) is missed at the time of pyeloplasty, a redo-pyeloplasty is often required. The aims were to analyze clinical predictors for the presence of a CRV in UPJO and the utility of functional magnetic resonance urography (fMRU) in preoperative identification of a crossing vessel. Using an Institutional Review Board approved registry database, we identified 166 patients from July of 2007 until January of 2014 who had undergone open, laparoscopic, or robotic assisted laparoscopic pyeloplasty at our institution. We abstracted data including age at surgery, preoperative symptoms, preoperative imaging findings, and whether or not a CRV was identified intraoperatively. Statistical analysis was performed on SPSS using the Mann-Whitney U test. Of the 166 patients identified, 78 were found to have a CRV at the time of surgery and 88 did not. The surgical approach was distributed as 104 robotic assisted laparoscopic, 51 open, and 11 pure laparoscopic. On univariate analysis, older age at presentation and pain at presentation predicted the presence of a CRV; antenatal hydronephrosis was a negative predictor, though 20 of 68 (25.6%) infants diagnosed with UPJO antenatally did have a CRV. Subgroup analysis of patients undergoing preoperative MRU showed a sensitivity of 88.2% and specificity of 91.7% for the detection of CRVs. This study confirmed the importance of looking for a crossing vessel in all cases, with the knowledge that increased age and pain at presentation were more likely to be associated with a crossing vessel. In addition, fMRU is a valuable source of information in the preoperative identification of the presence of a crossing vessel. The study has limitations including being retrospective in nature, and that the sensitivity of fMRU to identify CRVs was based on the read of an experienced uroradiologist who specializes in MRU, so may not correlate with the standard clinical read of an fMRU. This study confirms the need to maintain a high index of suspicion for the presence of a CRV when intervening in a clinically symptomatic older child, although 25% of infants with antenatally detected UPJO did have one too. Our subset analysis demonstrated that MRU is a reliable method of detecting crossing vessels. Copyright © 2015 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

KIM-1 Is a Potential Urinary Biomarker of Obstruction: Results from a Prospective Cohort Study.

PubMed

Olvera-Posada, Daniel; Dayarathna, Thamara; Dion, Marie; Alenezi, Husain; Sener, Alp; Denstedt, John D; Pautler, Stephen E; Razvi, Hassan

2017-02-01

Partial or complete obstruction of the urinary tract is a common and challenging urological condition that may occur in patients of any age. Serum creatinine is the most commonly used method to evaluate global renal function, although it has low sensitivity for early changes in the glomerular filtration rate or unilateral renal pathology. Hence, finding another measurable parameter that reflects the adaptation of the renal physiology to these circumstances is important. Several recent studies have assessed the use of new biomarkers of acute kidney injury (AKI), but the information among patients with stone disease and those with obstructive uropathy is limited. A prospective cohort study was conducted to determine the urinary levels of kidney injury molecule-1 (KIM-1), Total and Monomeric neutrophil gelatinase-associated lipocalin (NGAL) in patients with hydronephrosis secondary to renal stone disease, congenital ureteropelvic junction obstruction or ureteral stricture. Comparison between patients with hydronephrosis and no hydronephrosis was carried out along with correlation analysis to detect factors associated with biomarker expression. Urinary levels of KIM-1 significantly decreased after hydronephrosis treatment in patients with unilateral obstruction (1.19 ng/mL vs 0.76 ng/mL creatinine, p = 0.002), additionally KIM-1 was significantly higher in patients with hydronephrosis compared to stone disease patients without radiological evidence of obstruction (1.19 vs 0.64, p = 0.006). Total and Monomeric NGAL showed a moderate correlation with the presence of leukocyturia. We found that a KIM-1 value of 0.735 ng/mg creatinine had a sensitivity of 75% and specificity of 67% to predict the presence of hydronephrosis in preoperative studies (95% CI 0.58-0.87, p = 0.006). Our results show that KIM-1 is a promising biomarker of subclinical AKI associated with hydronephrosis in urological patients. NGAL values were influenced by the presence of leukocyturia, limiting its usefulness in this population.

The urologist and child hydronephrosis caused by ureteral anomalies.

PubMed

Bumbu, Gheorghe Adrian; Berechet, Mihail Claudius; Nacer, Karim; Bumbu, Gheorghe; Ionovici, Nina; Bumbu, Bogdan Andrei

2018-01-01

Congenital hydronephrosis caused by ureteral anomalies, like ureteral duplicity, megaureter, ureteral ectopy and ureterocele, must be differentiated from ureteropelvic junction obstruction (UJO) hydronephrosis and from the hydronephrosis caused by vesicoureteral reflux. These represent a differentiated branch of congenital abnormalities in children even if not so common, but this fact should not be disconsidered. Over a five years period, from 111 operated children in our Clinic, we performed 13 interventions for congenital hydronephrosis, 11 (84.61%) being caused by ureteral abnormalities. Here, there were described particular cases, with diagnosis steps and treatment decisions. Ureteral ectopy can be manifested by loss of urine drops in cases where ureteral holes are located in the vagina, septum or urethra, inferior to the sphincter mechanism. Incontinence in boys never occurs because the ectopic ureter never opens under the sphincter mechanism. If the ureter opens in the genital tract, patients may clinically present with the epididymitis symptom. From autopsy statistics in the US, the incidence of ureteral duplex is estimated to be less than 1%. When the duplex is associated with urinary infection, the incidence of ureteral duplex increases up to 8%.

Diagnostic accuracy of Onen's Alternative Grading System combined with Doppler evaluation of ureteral jets as an alternative in the diagnosis of obstructive hydronephrosis in children.

PubMed

de Bessa, Jose; Rodrigues, Cicilia M; Chammas, Maria Cristina; Miranda, Eduardo P; Gomes, Cristiano M; Moscardi, Paulo R; Bessa, Marcia C; Molina, Carlos A; Tiraboschi, Ricardo B; Netto, Jose M; Denes, Francisco T

2018-01-01

Ureteropelvic junction obstruction (UPJO) is a common congenital anomaly leading to varying degrees of hydronephrosis (HN), ranging from no apparent effect on the renal function to atrophy. Evaluation of these children is based on Diuretic Renal Scintigraphy (DRS) and Ultrasonography (US). Recent studies have suggested that new parameters of conventional and color Doppler ultrasonography (CDUS) may be useful in discriminating which kidneys are obstructed. The present study aims to assess the diagnostic accuracy of such parameters in the diagnosis of obstruction in children with UPJO. We evaluated 44 patients (33 boys) with a mean age of 6.53 ± 4.39 years diagnosed with unilateral high-grade hydronephrosis (SFU grades 3 and 4). All underwent DRS and index tests (conventional US and CDUS to evaluate ureteral jets frequency) within a maximum interval of two weeks. Hydronephrotic units were reclassified according to the alternative grading system (AGS) proposed by Onen et al. Obstruction in the DRS was defined as a differential renal function <40% on the affected side and/or features indicating poor drainage function like T1/2 >20 minutes after the administration of furosemide, and a plateau or ascending pattern of the excretion curve. Nineteen hydronephrotic units (43.1%) were obstructed. Some degree of cortical atrophy-grades 3 (segmental) or 4 (diffuse)-was present in those obstructed units. AGS grades had 100% sensitivity, 76% of specificity and 86.4% of accuracy. The absence of ureteral jets had a sensitivity of 73.68%, a specificity of 100% with an accuracy of 88.6%. When we analyzed the two aspects together and considered obstructed the renal units classified as AGS grade 3 or 4 with no jets, sensitivity increased to 78.9%, accuracy to 92%, remaining with a maximum specificity of 100%. These features combined would allow us to avoid performing DRS in 61% of our patients, leaving more invasive tests to inconclusive cases. Although DRS remains the mainstay to distinguishing obstructive from non-obstructive kidneys, grade of hydronephrosis and frequency of ureteral jets, independently or in combination may be a reliable alternative in the mostly cases.This alternative approach has high accuracy, it is less invasive, easily reproducible and may play a role in the diagnosis of obstruction in pediatric population.

Soft-tissue applications of the holmium:YAG laser in urology

NASA Astrophysics Data System (ADS)

Denstedt, John D.; Razvi, Hassan A.; Chun, Samuel S.; Sales, Jack L.

1995-05-01

The ideal surgical laser for the treatment of soft tissue pathology should possess both ablative and hemostatic abilities. As well, for use in urologic conditions the laser must also be suitable for endoscopic use. The Holmium:YAG laser possesses these qualities and in preliminary clinical use has demonstrated a variety of potential urologic applications. In this study we review our initial experience with the Holmium:YAG laser over a 18 month period. A total of 51 patients underwent 53 procedures for a variety of soft tissue conditions including: bladder tumor ablation (25), incision of ureteral stricture (15), incision of urethral stricture (6), treatment of ureteropelvic junction obstruction (3), incision of bladder neck contracture (2), and ablation of a ureteral tumor (2). Satisfactory hemostasis was achieved in all cases. Procedures were considered successful (no further intervention being required to treat the condition) in 81% of the cases. Two patients with dense bladder neck contractures required electroincision under the same anesthetic for completion of the procedure. A single complication, that of urinary extravasation following incision of a urethral stricture resolved with conservative management. In summary, the Holmium:YAG laser has demonstrated safety and proficiency in the treatment of a variety of urologic soft tissue conditions.

Serum and urinary thioredoxin concentrations are associated with severity of children hydronephrosis.

PubMed

Xu, Zhe-Ming; Li, Min-Ju; Tao, Chang

2017-03-01

Ureteropelvic junction obstruction (UPJO) is the most common cause of hydronephrosis in children. This study was to assess the relationship between serum thioredoxin (S-Trx) and urinary thioredoxin (U-Trx) concentrations and severity of children hydronephrosis caused by UPJO. This study included 156 hydronephrosis children with unilateral UPJO and 80 healthy children. S-Trx and U-Trx concentrations were measured using enzyme-linked immunosorbent assay. U-Trx/creatinine (cr) ratio was calculated. S-Trx and U-Trx concentrations and U-Trx/cr ratio were significantly higher in hydronephrosis children than in healthy children. They were significantly correlated with split renal function, anterior-posterior diameter and Society for Fetal Urology classification, as well as were independently related to the split renal function <39.2%, anterior-posterior diameter>30mm and Society for Fetal Urology grade IV. Under receiver operating characteristic curves, U-Trx/cr ratio showed the higher predictive value compared to S-Trx and U-Trx concentrations. Increased S-Trx and U-Trx concentrations, especially U-Trx/cr ratio, are closely associated with the severity of children hydronephrosis, substantializing Trx as a promising biomarker for the progression of children hydronephrosis. Copyright © 2017 Elsevier B.V. All rights reserved.

Cryotherapy of the nephrostomy tract: a novel technique to decrease the risk of hemorrhage after tubeless percutaneous renal surgery.

PubMed

Okeke, Zeph; Andonian, Sero; Srinivasan, Arun; Shapiro, Edan; Vanderbrink, Brian A; Kavoussi, Louis R; Smith, Arthur D

2009-03-01

Delayed hemorrhage and significant postoperative pain are associated with complex percutaneous renal surgery. Cryoablation of the percutaneous nephrostomy tract after endoscopic procedures is a potential means of preventing delayed renal hemorrhage. In this study, we investigated the efficacy of this technique by comparing a group of patients who underwent this approach with another group who had nephrostomy tube insertion after percutaneous renal surgery. Sixty patients with complex renal calculi or ureteropelvic junction (UPJ) obstruction underwent percutaneous endoscopic management of their disease. At the conclusion of the procedure, 30 consecutive patients underwent a single 10-minute freeze-thaw cycle, in which a cryoprobe traversed the nephrostomy tract. These 30 patients were compared with the preceding 30 patients who had a nephrostomy tube inserted after complex percutaneous renal surgery. The two groups were well matched in terms of age, body mass index, total stone burden, number of patients with full staghorn calculi, and number of patients with concomitant UPJ obstruction. The cryotherapy group had a significantly shorter hospital stay (2.1 v 3.6 days, P < 0.001); decreased rates of delayed bleeding episodes (3% v 13%, P < 0.001), and urinary leak (0% v 10%, P < 0.001). Cryotherapy of the nephrostomy is a novel means of decreasing the risk of delayed postoperative hemorrhage after complex percutaneous renal surgery. It is associated with significantly decreased length of hospitalization postoperatively, as well as decreased risk of urine leakage compared with nephrostomy tubes in these groups of patients.

A 5-Fr Externalized Nephroureteral Catheter as the Sole Protective Device for Pediatric Pyeloplasty: The Experiences of 142 Patients.

PubMed

Mollaeian, Mansour; Ghavami-Adel, Maryam; Eskandari, Farid; Mollaeian, Arash

2016-10-01

Pyeloplasty for ureteropelvic junction obstruction correction is a common procedure, but the optimal method for protective diversion after pyeloplasty is still a matter of debate. Here, we present our clinical trial experience using a single percutaneous externalized nephroureteral (NU) 5-Fr catheter (infant feeding tube) with multiple side holes as the sole instrument of drainage to provide a protective mechanism. In this prospective study, we analyzed the charts of 142 patients who underwent pyeloplasty from August 2001 through October 2008. We used a single externalized NU 5-Fr catheter with multiple side holes for postoperative upper tract diversion. The catheter was removed in the office after 10 - 14 days. Complications from the use of this catheter, including poor catheter function, premature dislodgement, urinary tract infection, leakage, urinoma, and anastomotic stenosis, were evaluated. The operations were performed by two surgeons at two separate centers. In all, 148 pyeloplasty procedures were performed on 142 patients. The mean hospital stay length was 2 (1 - 3) days. A contrast study through a catheter demonstrated excellent drainage with no leakage in all patients. Immediately after catheter removal, febrile urinary tract infection and transient obstructive symptoms and signs occurred in 15 patients. Using a percutaneous externalized NU 5-Fr catheter was sufficient as a protective measure after open pyeloplasty. It costs less than other diverting systems, such as DJ, and can be removed in the office. Therefore, it can be a safe and cost effective procedure, especially in developing countries where cystoscopic set ups are not readily available. There were only a few notable complications.

Assessing Urinary Tract Junction Obstruction Defects by Methylene Blue Dye Injection.

PubMed

Yun, Kangsun

2017-10-12

Urinary tract junction obstruction defects are congenital anomalies inducing hydronephrosis and hydroureter. Murine urinary tract junction obstruction defects can be assessed by tracking methylene blue dye flow within the urinary system. Methylene blue dye is injected into the renal pelvis of perinatal embryonic kidneys and dye flow is monitored from the renal pelvis of the kidney through the ureter and into the bladder lumen after applying hydrostatic pressure. Dye accumulation will be evident in the bladder lumen of the normal perinatal urinary tract, but will be constrained between the renal pelvis and the end point of an abnormal ureter, if urinary tract obstructions occur. This method facilitates the confirmation of urinary tract junction obstructions and visualization of hydronephrosis and hydroureter. This manuscript describes a protocol for methylene blue dye injection into the renal pelvis to confirm urinary tract junction obstructions.

One-trocar-assisted pyeloplasty: An attractive alternative to open pyeloplasty

PubMed Central

Marte, Antonio; Papparella, Alfonso

2015-01-01

Background: To survey the effects of one-trocar-assisted pyeloplasty (OTAP) in the treatment of ureteropelvic junction obstruction (UPJO) in kids. Materials and Methods: Forty-four children (±3.5 years) were submitted to OTAP procedure. A flank incision under the XII rib was made, the Gerota's fascia was achieved and a balloon Hasson trocar with an operative telescope inserted for retroperitoneal access. The renal pelvis and ureter were isolated and exteriorised. Forty-two patients underwent Anderson-Hynes dismembered and one Fenger pyeloplasty. One patient was converted to an open procedure. Two patients presented an aberrant crossing vessel. In all patients, a double J stent was positioned. The operative time and length of stay (LOS) were evaluated. Renal scan and ultrasound (US) were utilised to evaluate the results from 6 to 12 months. Results: OTAP was successful in all but 1 patient. Mean operative time and LOS were 128 min and 3,5 days. We had four operative complications (9.09%). The US and a nuclear scan confirmed the resolution of the UPJO in all patients except one with the Fenger pyeloplasty who had an open Anderson-Hynes. Conclusions: The combination of retroperitoneoscopic and open procedures for dismembered pyeloplasty offers a simple, time-saving method in a minimally invasive fashion with low morbidity for patients with UPJO. PMID:26712293

One-trocar-assisted pyeloplasty: An attractive alternative to open pyeloplasty.

PubMed

Marte, Antonio; Papparella, Alfonso

2015-01-01

To survey the effects of one-trocar-assisted pyeloplasty (OTAP) in the treatment of ureteropelvic junction obstruction (UPJO) in kids. Forty-four children (±3.5 years) were submitted to OTAP procedure. A flank incision under the XII rib was made, the Gerota's fascia was achieved and a balloon Hasson trocar with an operative telescope inserted for retroperitoneal access. The renal pelvis and ureter were isolated and exteriorised. Forty-two patients underwent Anderson-Hynes dismembered and one Fenger pyeloplasty . One patient was converted to an open procedure. Two patients presented an aberrant crossing vessel. In all patients, a double J stent was positioned. The operative time and length of stay (LOS) were evaluated. Renal scan and ultrasound (US) were utilised to evaluate the results from 6 to 12 months. OTAP was successful in all but 1 patient. Mean operative time and LOS were 128 min and 3,5 days. We had four operative complications (9.09%). The US and a nuclear scan confirmed the resolution of the UPJO in all patients except one with the Fenger pyeloplasty who had an open Anderson-Hynes. The combination of retroperitoneoscopic and open procedures for dismembered pyeloplasty offers a simple, time-saving method in a minimally invasive fashion with low morbidity for patients with UPJO.

MCDK, UPJO, and VUR: A common genetic cause

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

Robson, W.L.M.; Rogers, R.C.; Leung, A.K.C.

1995-11-20

Devriendt and Fryns suggest the possibility that multicystic dysplasia of the kidney (MCDK) and uretero-pelvic junction obstruction (UPJO) may have a common genetic cause transmitted as an autosomal dominant disorder with variable expression, and that a candidate gene is localized on chromosome arm 6p. Izquierdo et al. reported that 4 of 5 families with autosomal dominant hereditary hydronephrosis demonstrated linkage to the major histocompatibility locus at 6p21. Fryns et al. provide further support for their hypothesis by reporting a fetus with bilateral MCDK and an associated de novo balanced translocation (6;19) (p23.1; q13.4). We agree that a genetically determined disturbancemore » in blood supply to the ureteric bud might cause MCDK and UPJO. Devriendt and Fryns further suggest that vesico-ureteral reflux (VUR) might also be caused by permutations of the candidate gene on 6p. Contralateral VUR has been reported in 11 to 28% of patients with MCDK. In patients with unilateral renal agenesis (URA), VUR has been noted in 15 to 30% of patients. VUR has been noted in up to 40% of patients with UPJO. The frequent occurrence of VUR in URA, MCDK, and UPJO supports the suggestion by Devriendt and Fryns that this association might be linked to different mutations in a single gene. 10 refs.« less

Lessons from 90 consecutive laparoscopic dismembered pyeloplasties in a residency program.

PubMed

Arap, Marco Antonio; Torricelli, Fabio Cesar Miranda; Mitre, Anuar Ibrahim; Chambo, Jose Luis; Duarte, Ricardo Jordão; Srougi, Miguel

2013-08-01

The aim of this study was to report on the safety and efficacy of 90 consecutive laparoscopic pyeloplasties carried out in a university hospital. The outcomes of 90 transperitoneal dismembered pyeloplasties that were performed by residents at the hospital from March 2004 to March 2010 were analyzed. All of the surgeries were performed because of symptomatic ureteropelvic junction obstruction. The laparoscopic Anderson-Hynes dismembered technique was used in all cases, and a double-J stent was routinely placed and left in place for 4 weeks. The patients were followed up clinically and with imaging studies. Clinical data, outcomes and complication rates for the patients were retrospectively reviewed using a prospectively maintained database. The mean patient age was 38.9 (10-80) years, and 46 patients (51.1%) were males. The mean operative time was 222.5 (125-400) min. The surgery was completed laparoscopically in 96.6% of cases (87 patients). Conversion was required owing to technical difficulties in three cases. Overall, four (4.4%) patients had major complications. Seventy-six of the 87 patients (87.3%) presented improvements in symptomatology at a median follow-up of 39.7 (6-75) months. Laparoscopic pyeloplasty is feasible and associated with high success and low complication rates, even in a residency program.

Emergency extracorporeal shockwave lithotripsy for acute renal colic caused by upper urinary-tract stones.

PubMed

Kravchick, Sergey; Bunkin, Igor; Stepnov, Eugeny; Peled, Ronit; Agulansky, Leonid; Cytron, Shmuel

2005-01-01

To evaluate emergency SWL for the treatment of upper urinary-tract stones causing renal colic. Between January 1999 and June 2003, 53 patients with a mean age of 46.6 years (range 22-65 years) were enrolled. The inclusion criteria were acute renal colic, radiopaque 5-mm to 1.5-cm calculi in the ureteropelvic junction (N=10) or upper ureter (N=43), and no evidence of urinary-tract infection or acute renal failure. The mean stone size was 7.14 mm (range 5-13 mm). Patients were randomly assigned to the control (N=28) and study (N=25) groups using previously prepared cards in envelopes. Patients in the study group underwent emergency SWL, while patients in the control group underwent scheduled SWL within 30 days. Stone status was evaluated 4 weeks after lithotripsy. There was no significant difference between the control and study groups with respect to age, sex, stone location or volume, renal obstruction, or days spent in the hospital for pain control. Available fragments of stones were sent for infrared spectroscopy. Preoperative and postoperative data were compared in the two groups using SPSS 10.0 statistical software. The SWL treatment lasted 50+/-11 minutes. The stone-free rates were 72% and 64% and the efficiency quotients were 53% and 44% in study and control groups, respectively. Patients in the control group spent more time in the hospital (P=0.014) and in recovery at home (P=0.011). Emergency SWL for acute renal colic caused by upper-ureteral stones is a safe procedure and offers effective release from pain and obstruction. It also decreases hospitalization days and hastens return to normal activity.

Comparison of Robotic Pyeloplasty and Standard Laparoscopic Pyeloplasty in Infants: A Bi-Institutional Study.

PubMed

Neheman, Amos; Kord, Eyal; Zisman, Amnon; Darawsha, Abd Elhalim; Noh, Paul H

2018-04-01

To compare outcomes between robotic pyeloplasty (RP) and standard laparoscopic pyeloplasty (LP) in the infant population for the treatment of ureteropelvic junction (UPJ) obstruction. We performed a retrospective cohort study of all children under 1 year of age who underwent RP or LP at two different medical centers between October 2009 and February 2016. Patient demographics, perioperative data, complications, and results were reviewed. Thirteen patients underwent standard LP, and 21 patients underwent RP during the study period. Median age and median weight at time of operation for the whole cohort were 6.1 months and 7.9 kg. Surgery success rates were similar with 95% and 92% in RP and LP, respectively. There was no statistically significant difference in operating time between the 2 groups, with a median time of 156 minutes in RP (range 125-249) and 192 minutes (range 98-229) in standard LP (P = .35). Median length of hospital stay was significantly shorter in the robotic group with a median stay of 1 day (range 1-3) and 7 days (range 7-12) in the standard LP group.(P < .0001) Drains or nephrostomy tubes were used more often in the laparoscopic group (100%, 13/13) as opposed to RP (9.5%, 2/21, P < .0001) There was a comparable complication rate between the 2 groups, 30.8% for LP and 23.8% for RP (P = .65). The minimally invasive dismembered pyeloplasty is safe and effective in the infant population and produces high success rates. The results, complication rates, and operative time were comparable between the two surgical methods while the standard LP demonstrated longer hospital stay. Both the robotic approach and the LP can be successfully utilized for the benefit of infants with UPJ obstruction.

Complete daVinci versus laparoscopic pyeloplasty: cost analysis.

PubMed

Bhayani, Sam B; Link, Richard E; Varkarakis, John M; Kavoussi, Louis R

2005-04-01

Computer-assisted pyeloplasty with the daVinci system is an emerging technique to treat ureteropelvic junction (UPJ) obstruction. A relative cost analysis was performed assessing this technology in comparison with purely laparoscopic pyeloplasty. Eight patients underwent computer-assisted (daVinci) dismembered pyeloplasty (CP) via a transperitoneal four-port approach. They were compared with 13 patients who underwent purely laparoscopic pyeloplasty (LP). All patients had a primary UPJ obstruction and were matched for age, sex, and body mass index. The cost of equipment and capital depreciation for both procedures, as well as assessment of room set-up time, takedown time, and personnel were analyzed. Surgeons and nursing staff for both groups were experienced in both laparoscopy and daVinci procedures. One- and two-way financial analysis was performed to assess relative costs. The mean set-up and takedown time was 71 minutes for CP and 49 minutes for LP. The mean length of stay was 2.3 days for CP and 2.5 days for LP. The mean operating room (OR) times for CP and LP were 176 and 210 minutes, respectively. There were no complications in either group. One-way cost analysis with an economic model showed that LP is more cost effective than CP at our hospital if LP OR time is <338 minutes. With adjustment to a volume of 500 daVinci cases/year, CP is still not as cost effective as LP. Two-way sensitivity analysis shows that in-room time must still be <130 minutes and yearly cases must be >500 to obtain cost equivalence for CP. Perioperative parameters for CP are encouraging. However, the costs are a clear disadvantage. In our hospital, it is more cost effective to teach and perform LP than to perform CP.

External extension of double-J ureteral stent during pyeloplasty: inexpensive stent and non-cystoscopic removal.

PubMed

Kajbafzadeh, Abdol-Mohammad; Zeinoddini, Atefeh; Ebadi, Maryam; Heidari, Reza; Tajalli, Afshin

2014-04-01

The purpose of the study is to describe our experience with the application of externalized double-J ureteral stent (DJUS) during pyeloplasty for correction of ureteropelvic junction obstruction (UPJO) in order to avoid cystoscopy for stent removal. Pyeloplasty was performed in 523 infants with UPJO using miniature pyeloplasty technique. After removing the obstructed segment, a 3-Fr. DJUS was placed into the ureter. In order to avoid cystoscopy for the removal of the stent, a feeding tube was passed through the skin and renal pelvis via a separate stab incision, connected to the DJUS and secured to the external body surface (skin), and the pyeloplasty was completed. The feeding tube along with the stent was removed after 3-4 weeks, respectively. Postoperative follow-up visits were performed 1, 3, and 6 months after the procedure. The mean operative time was 49 min (range 41-79). Patients were discharged after 17 ± 2 h (mean ± SD). No patient experienced bladder spasm or anticholinergic administration. Forty-four patients (8.4 %) experienced minor complications including non-febrile urinary tract infections and mild hematuria. No major complication including urinoma, leakage, and stent migration or displacement was observed during the follow-up period. Stent removal was tolerated by 99.8 % of patients in an outpatient setting with minimal discomfort without performing cystoscopy. Using external DJUS along with a pyelocutaneous stent extension during pyeloplasty is a safe, feasible, and beneficial technique. This technique resulted in high success rate with minimal cost and no renal injury. The non-cystoscopic stent removal and elimination of urethral catheterization following pyeloplasty are the other advantages of this technique.

Diuretic renography in evaluating dilated upper urinary tract in children

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

Ireton, R.C.; Parker, R.M.; Hayden, P.

1987-02-01

The diuretic renogram provides a previously unavailable noninvasive method for assessing and following urinary tract dilation of diverse cause, and defining true obstruction in children. Technetium-99m-DTPA (diethylenetriaminepentaacetic acid) is injected intravenously and a posteriorly placed gamma scintillation camera used to image the kidneys, ureters, and bladder. Furosemide is subsequently injected to stimulate a diuresis, and the washout pattern of isotope is monitored (time-activity histogram). Nonobstructive, obstructive, and poor renal function patterns were seen. Forty patients with varying degrees of hydroureteronephrosis were evaluated. Tracings were performed serially and compared with the clinical course in time, as well as with pressure flowmore » studies and operative findings. All patients with a nonobstructed diuretic renogram did well, except for 1 boy in whom ureteropelvic obstruction developed later. Difficulty in evaluating the obstructive renogram pattern occurred only in some children with severe (grade V) hydronephrosis. Further standardization of the diuretic renogram with regard to time of diuretic injection, state of patient hydration, and regions of imaging may improve diagnostic accuracy.« less

T-Box Genes in the Kidney and Urinary Tract.

PubMed

Kispert, A

2017-01-01

T-box (Tbx) genes encode an ancient group of transcription factors that play important roles in patterning, specification, proliferation, and differentiation programs in vertebrate organogenesis. This is testified by severe organ malformation syndromes in mice homozygous for engineered null alleles of specific T-box genes and by the large number of human inherited organ-specific diseases that have been linked to mutations in these genes. One of the organ systems that has not been associated with loss of specific T-box gene function in human disease for long is the excretory system. However, this has changed with the finding that mutations in TBX18, a member of a vertebrate-specific subgroup within the Tbx1-subfamily of T-box transcription factor genes, cause congenital anomalies of the kidney and urinary tract, predominantly hydroureter and ureteropelvic junction obstruction. Gene expression analyses, loss-of-function studies, and lineage tracing in the mouse suggest a primary role for this transcription factor in specifying the ureteric mesenchyme in the common anlage of the kidney, the ureter, and the bladder. We review the function of Tbx18 in ureterogenesis and discuss the body of evidence that Tbx18 and other members of the T-box gene family, namely, Tbx1, Tbx2, Tbx3, and Tbx20, play additional roles in development and homeostasis of other components of the excretory system in vertebrates. © 2017 Elsevier Inc. All rights reserved.

Preliminary experience and learning curve for laparoendoscopic single-site retroperitoneal pyeloplasty.

PubMed

Ou, Zhenyu; Qi, Lin; Yang, Jinrui; Chen, Xiang; Cao, Zhenzhen; Zu, Xiongbing; Liu, Longfei; Wang, Long

2013-09-01

To report our preliminary experience and to assess the learning curve for laparoendoscopic single-site retroperitoneal pyeloplasty (LESS-RP) for ureteropelvic junction obstruction (UPJO). From July 2010 to February 2012, LESS-RP was performed in 27 patients affected with UPJO by a single surgeon. A homemade single-access platform and both conventional and prebent instruments were applied. Patient characteristics and perioperative outcomes were analyzed. The cumulative sum (CUSUM) method was used to evaluate the learning curve. The LESS-RP was successfully accomplished in all 27 patients. The mean operative time (OT) was 175.9±22.5 minutes, and the mean estimated blood loss was 83.3±27.1 mL. We used the OT as a proxy to assess the learning curve. The CUSUM learning curve can be divided into two distinct phases: the initial 12 cases and the last 15 cases. There were significant differences in the mean OT (195.6 minutes versus 159.1 minutes, P<.001) and mean estimated blood loss (97.2 mL versus 72.2 mL, P=.014) between the two phases. The two phases did not differ in other parameters. LESS-RP is a safe and feasible procedure. The learning curve of a single surgeon suggests that the initial learning phase for LESS-RP can be completed after approximately 12 cases.

Predictors for the need of surgery in antenatally detected hydronephrosis due to UPJ obstruction--a prospective multivariate analysis.

PubMed

Arora, S; Yadav, P; Kumar, M; Singh, S Kumar; Sureka, S Kumar; Mittal, V; Ansari, M S

2015-10-01

Disagreement exists over the ability of different diagnostic tests to define obstruction, indications and timing of surgery and which patients will benefit from surgical intervention in antenatal hydronephrosis (ANH) due to ureteropelvic junction obstruction (UPJO). We try to find a way to predict which patients of ANH due to UPJO will eventually need surgery during conservative management. Prospective single centre study involving 122 renal units at a referral centre in India. Patients on conservative management were followed using a standard protocol and operated for pre-defined indications defining failure of conservative management. Patients who underwent surgery were compared with the non-operated group in terms of sex, side, baseline grade of hydronephrosis, maximum anterioposterior diameter on first postnatal ultrasound and differential renal function on first renal scan. A total of 109 renal units qualified for conservative management. Of those, 23.9% required operative intervention during follow-up. Median time to failure of conservative management was 37 weeks. The median follow-up of non-operated cases was 54 months. Univariate analysis revealed that society of fetal urology (SFU) grade of hydronephrosis, anteroposterior diameter (APD), cortical thickness (CT), and pre-operative differential renal function (DRF) had a significant association with surgery (P < 0.05). Multivariate analysis revealed APD and pre-operative DRF as the only independent predictors for requiring surgery, while CT and initial SFU grade of hydronephrosis were not. Receiver operating curve analysis showed that an APD of 24.3 mm could predict the need for surgery, with a sensitivity of 73.1% and a specificity of 88.0%. APD and DRF are the predictive factors for surgery. We stop short of recommending surgery only on the basis of APD. Instead we recommend that efforts be made to improve the specificity of this criterion, or by using APD in perspective with the differential renal function. We can reduce the burden of investigations in those with APD <24 mm while those with APD >24 mm can be more comprehensively monitored. Copyright © 2015 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

Late endovascular removal of Günther-Tulip inferior vena cava filter and stent reconstruction of chronic post-thrombotic iliocaval obstruction after 4753 days of filter dwell time: a case report with review of literature.

PubMed

Doshi, Mehul Harshad; Narayanan, Govindarajan

2016-12-01

Chronic post-thrombotic obstruction of the inferior vena cava (IVC) or iliocaval junction is an uncommon complication of long indwelling IVC filter. When such an obstruction is symptomatic, endovascular treatment options include stent placement with or without filter retrieval. Filter retrieval becomes increasingly difficult with longer dwell times. We present a case of symptomatic post-thrombotic obstruction of the iliocaval junction related to Günther-Tulip IVC filter (Cook Medical Inc, Bloomington, IN) with dwell time of 4753 days, treated successfully with endovascular filter removal and stent reconstruction. Filter retrieval and stent reconstruction may be a treatment option in symptomatic patients with filter-related chronic IVC or iliocaval junction obstruction, even after prolonged dwell time.

A Prospective Comparison of Robotic and Laparoscopic Pyeloplasty

PubMed Central

Link, Richard E.; Bhayani, Sam B.; Kavoussi, Louis R.

2006-01-01

Objective: To determine whether robotic-assisted pyeloplasty (RLP) has any significant clinical or cost advantages over laparoscopic pyeloplasty (LP) for surgeons already facile with intracorporeal suturing. Summary Background Data: LP has become an established management approach for primary ureteropelvic junction obstruction. More recently, the da Vinci robot has been applied to this procedure (RLP) in an attempt to shorten the learning curve. Whether RLP provides any significant advantage over LP for the experienced laparoscopist remains unclear. Methods: Ten consecutive cases each of transperitoneal RLP and LP performed by a single surgeon were compared prospectively with respect to surgical times and perioperative outcomes. Cost assessment was performed by sensitivity analysis using a mathematical cost model incorporating operative time, anesthesia fees, consumables, and capital equipment depreciation. Results: The RLP and LP groups had statistically indistinguishable demographics, pathology, and similar perioperative outcomes. Mean operative and total room time for RLP was significantly longer than LP by 19.5 and 39.0 minutes, respectively. RLP was much more costly than LP (2.7 times), due to longer operative time, increased consumables costs, and depreciation of the costly da Vinci system. However, even if depreciation was eliminated, RLP was still 1.7 times as costly as LP. One-way sensitivity analysis showed that LP operative time must increase to almost 6.5 hours for it to become cost equivalent to RLP. Conclusions: For the experienced laparoscopist, application of the da Vinci robot resulted in no significant clinical advantage and added substantial cost to transperitoneal laparoscopic dismembered pyeloplasty. PMID:16552199

A prospective comparison of robotic and laparoscopic pyeloplasty.

PubMed

Link, Richard E; Bhayani, Sam B; Kavoussi, Louis R

2006-04-01

To determine whether robotic-assisted pyeloplasty (RLP) has any significant clinical or cost advantages over laparoscopic pyeloplasty (LP) for surgeons already facile with intracorporeal suturing. LP has become an established management approach for primary ureteropelvic junction obstruction. More recently, the da Vinci robot has been applied to this procedure (RLP) in an attempt to shorten the learning curve. Whether RLP provides any significant advantage over LP for the experienced laparoscopist remains unclear. Ten consecutive cases each of transperitoneal RLP and LP performed by a single surgeon were compared prospectively with respect to surgical times and perioperative outcomes. Cost assessment was performed by sensitivity analysis using a mathematical cost model incorporating operative time, anesthesia fees, consumables, and capital equipment depreciation. The RLP and LP groups had statistically indistinguishable demographics, pathology, and similar perioperative outcomes. Mean operative and total room time for RLP was significantly longer than LP by 19.5 and 39.0 minutes, respectively. RLP was much more costly than LP (2.7 times), due to longer operative time, increased consumables costs, and depreciation of the costly da Vinci system. However, even if depreciation was eliminated, RLP was still 1.7 times as costly as LP. One-way sensitivity analysis showed that LP operative time must increase to almost 6.5 hours for it to become cost equivalent to RLP. For the experienced laparoscopist, application of the da Vinci robot resulted in no significant clinical advantage and added substantial cost to transperitoneal laparoscopic dismembered pyeloplasty.

Tubular Obstruction Leads to Progressive Proximal Tubular Injury and Atubular Glomeruli in Polycystic Kidney Disease

PubMed Central

Galarreta, Carolina I.; Grantham, Jared J.; Forbes, Michael S.; Maser, Robin L.; Wallace, Darren P.; Chevalier, Robert L.

2015-01-01

In polycystic kidney disease (PKD), renal parenchyma is destroyed by cysts, hypothesized to obstruct nephrons. A signature of unilateral ureteral obstruction, proximal tubular atrophy leads to formation of atubular glomeruli. To determine whether this process occurs in PKD, kidneys from pcy mice (moderately progressive PKD), kidneys from cpk mice (rapidly progressive PKD), and human autosomal dominant PKD were examined in early and late stages. Integrity of the glomerulotubular junction and proximal tubular mass were determined in sections stained with Lotus tetragonolobus lectin. Development of proximal tubular atrophy and atubular glomeruli was determined in serial sections of individual glomeruli. In pcy mice, most glomerulotubular junctions were normal at 20 weeks, but by 30 weeks, 56% were atrophic and 25% of glomeruli were atubular; glomerulotubular junction integrity decreased with increasing cyst area (r = 0.83, P < 0.05). In cpk mice, all glomerulotubular junctions were normal at 10 days, but by 19 days, 26% had become abnormal. In early-stage autosomal dominant PKD kidneys, 50% of glomeruli were atubular or attached to atrophic tubules; in advanced disease, 100% were abnormal. Thus, proximal tubular injury in cystic kidneys closely parallels that observed with ureteral obstruction. These findings support the hypothesis that, in renal cystic disorders, cyst-dependent obstruction of medullary and cortical tubules initiates a process culminating in widespread destruction of proximal convoluted tubules at the glomerulotubular junction. PMID:24815352

Pelvi-ureteric junction obstruction related to crossing vessels: vascular anatomic variations and implication for surgical approaches.

PubMed

Panthier, Frédéric; Lareyre, Fabien; Audouin, Marie; Raffort, Juliette

2018-03-01

Pelvi-ureteric junction obstruction corresponds to an impairment of urinary transport that can lead to renal dysfunction if not treated. Several mechanisms can cause the obstruction of the ureter including intrinsic factors or extrinsic factors such as the presence of crossing vessels. The treatment of the disease relies on surgical approaches, pyeloplasty being the standard reference. The technique consists in removing the pathologic ureteric segment and renal pelvis and transposing associated crossing vessels if present. The vascular anatomy of the pelvi-ureteric junction is complex and varies among individuals, and this can impact on the disease development and its surgical treatment. In this review, we summarize current knowledge on vascular anatomic variations in the pelvi-ureteric junction. Based on anatomic characteristics, we discuss implications for surgical approaches during pyeloplasty and vessel transposition.

The roles of serum and urinary carbohydrate antigen 19-9 in the management of patients with antenatal hydronephrosis.

PubMed

Atar, Arda; Oktar, Tayfun; Kucukgergin, Canan; Kalelioglu, Ibrahim; Seckin, Sule; Ander, Haluk; Ziylan, Orhan; Kadioglu, Teoman Cem

2015-06-01

Serum carbohydrate antigen (CA) 19-9 has been clinically applied as a valuable tumor marker for pancreatic and gastrointestinal carcinoma. CA 19-9 is expressed in normal excretory epithelium tissues. Increased CA 19-9 has also been observed in uroepithelial tumors as well as in nonmalignant conditions including hydronephrosis secondary to ureteral stones. The purpose of this article is to evaluate the role of urinary CA 19-9 as a non-invasive biomarker in the postnatal differentiation of obstructive and non-obstructive hydronephrosis in patients with unilateral antenatal hydronephrosis. Infants with isolated renal pelvic dilatation, defined as the presence of anteroposterior pelvic diameter (APPD) equal to or greater than 7 mm based on antenatal ultrasound after 28 weeks' gestation, underwent systematic investigation for uropathies and were prospectively followed up. The pyeloplasty group consisted of 17 patients with ureteropelvic junction (UPJ) obstruction who had undergone pyeloplasty. The non-obstructive dilatation (NOD) group consisted of 17 patients with non-obstructive hydronephrosis, and the control group consisted of 21 healthy children. Commercial enzyme-linked immunosorbent assay (ELISA) kits were used to measure the urinary and serum CA 19-9 levels. In both hydronephrosis groups (pyeloplasty and non-obstructive dilatation), the correlations between urinary and serum CA 19-9 levels with the anteroposterior pelvic diameter measured at the third trimester and the postnatal initial evaluation and differential renal function were investigated. The initial median urinary CA 19-9 levels were significantly greater in children who underwent pyeloplasty than in both the non-obstructive hydronephrosis (143 ± 38 vs. 68 ± 23, respectively; p = 0.007) and the healthy control groups (143 ± 38 vs. 13 ± 3, respectively; p = 0.001) (Figure). Three months after surgery, the urinary CA 19-9 levels had decreased significantly according to the preoperative levels in the pyeloplasty group (143 ± 38 vs. 55 ± 16, p = 0.039). In both the pyeloplasty and NOD groups, there was a correlation of urinary CA 19-9 levels with differential renal function and a correlation of serum CA 19-9 levels with the initial anteroposterior pelvic diameter. Receiver operator characteristic (ROC) analysis revealed a better diagnostic profile for the urinary CA 19-9 level than for the serum CA 19-9 level in terms of identifying obstruction in the hydronephrosis groups (areas under the curve = 0.8 and 0.7, respectively). The best cut-off value of for urinary CA 19-9 was 85.5 U/mL with 76% sensitivity, 85% specificity. The negative predictive value was 80%. The results suggest that voided urine CA 19-9 levels seems to be a more useful marker than serum CA 19-9 in obstructive dilatation. An appropriate decrease in urinary CA 19-9 levels after pyeloplasty may be used as a predictor of surgical outcome. In addition, the results have a number of important diagnostic implications that should be further validated in a larger study population. Based on these results, we suggest that a high urinary CA 19-9 level is a non-invasive clinically applicable marker for differentiating between obstruction and non-obstructive dilatation. Copyright © 2015 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

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.

Small bowel entrapment and ureteropelvic junction disruption associated with L3 Chance fracture-dislocation.

PubMed

Pesenti, Sebastien; Blondel, Benjamin; Faure, Alice; Peltier, Emilie; Launay, Franck; Jouve, Jean-Luc

2016-09-16

Paediatric Chance fracture are rare lesions but often associated with abdominal injuries. We herein present the case of a seven years old patient who sustained an entrapment of small bowel and an ureteropelvic disruption associated with a Chance fracture and spine dislocation following a traffic accident. Initial X-rays and computed tomographic (CT) scan showed a Chance fracture with dislocation of L3 vertebra, with an incarceration of a small bowel loop in the spinal canal and a complete section of the left lumbar ureter. Paraplegia was noticed on the initial neurological examination. A posterior L2-L4 osteosynthesis was performed firstly. In a second time she underwent a sus umbilical laparotomy to release the incarcerated jejunum loop in the spinal canal. An end-to-end anastomosis was performed on a JJ probe to suture the left injured ureter. One month after the traumatism, she started to complain of severe headaches related to a leakage of cerebrospinalis fluid. Three months after the traumatism there was a clear regression of the leakage. One year after the trauma, an anterior intervertebral fusion was done. At final follow-up, no neurologic recovery was noticed. In case of Chance fracture, all physicians should think about abdominal injuries even if the patient is asymptomatic. Initial abdominal CT scan and magnetic resonance imaging provide in such case crucial info for management of the spine and the associated lesions.

Use of new technology in endourology and laparoscopy by american urologists: internet and postal survey.

PubMed

Kim, H L; Hollowell, C M; Patel, R V; Bales, G T; Clayman, R V; Gerber, G S

2000-11-01

To assess the use of new technology by American urologists. Using the American Urological Association directory, surveys were sent via the U.S. postal service to 1000 randomly selected American urologists and 3065 urologists who had an Internet address listed in the directory. Responses were received from 601 urologists (415 postal, 186 Internet). Overall, 81% of survey respondents reported performing fewer or the same number of percutaneous procedures as compared with 3 to 4 years ago and 84% reported carrying out more or the same number of ureteroscopic procedures in the treatment of patients with stone disease. Open dismembered pyeloplasty (43%) and Acucise endopyelotomy (42%) were most frequently reported as the preferred treatment for adult patients with symptomatic ureteropelvic junction obstruction. Although 60% of respondents reported that they have taken a laparoscopy course, 67% currently do not perform any laparoscopy in their practice. In addition, only 7% of urologists stated that laparoscopy comprises more than 5% of their practice. When stratified by the number of years in practice, those in practice less than 10 years were more likely than those in practice 10 to 20 years and those in practice longer than 20 years to have performed an endopyelotomy (77%, 60%, and 48%, respectively, P <0.001) and to be currently performing laparoscopy (49%, 36%, and 18%, respectively, P <0.001). Compared with 3 to 4 years ago, American urologists are performing more ureteroscopy and fewer percutaneous stone procedures. Although most urologists have taken laparoscopy courses, this modality has not been widely incorporated into their practices at present.

First in Human Clinical Trial of Ultrasonic Propulsion of Kidney Stones.

PubMed

Harper, Jonathan D; Cunitz, Bryan W; Dunmire, Barbrina; Lee, Franklin C; Sorensen, Mathew D; Hsi, Ryan S; Thiel, Jeff; Wessells, Hunter; Lingeman, James E; Bailey, Michael R

2016-04-01

Ultrasonic propulsion is a new technology using focused ultrasound energy applied transcutaneously to reposition kidney stones. We report what are to our knowledge the findings from the first human investigational trial of ultrasonic propulsion toward the applications of expelling small stones and dislodging large obstructing stones. Subjects underwent ultrasonic propulsion while awake without sedation in clinic, or during ureteroscopy while anesthetized. Ultrasound and a pain questionnaire were completed before, during and after propulsion. The primary outcome was to reposition stones in the collecting system. Secondary outcomes included safety, controllable movement of stones and movement of stones less than 5 mm and 5 mm or greater. Adverse events were assessed weekly for 3 weeks. Kidney stones were repositioned in 14 of 15 subjects. Of the 43 targets 28 (65%) showed some level of movement while 13 (30%) were displaced greater than 3 mm to a new location. Discomfort during the procedure was rare, mild, brief and self-limited. Stones were moved in a controlled direction with more than 30 fragments passed by 4 of the 6 subjects who had previously undergone a lithotripsy procedure. The largest stone moved was 10 mm. One patient experienced pain relief during treatment of a large stone at the ureteropelvic junction. In 4 subjects a seemingly large stone was determined to be a cluster of small passable stones after they were moved. Ultrasonic propulsion was able to successfully reposition stones and facilitate the passage of fragments in humans. No adverse events were associated with the investigational procedure. Copyright © 2016 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Diagnostic accuracy of neonatal kidney ultrasound in children having antenatal hydronephrosis without ureter and bladder abnormalities.

PubMed

Rianthavorn, Pornpimol; Limwattana, Sorawan

2015-10-01

To determine the diagnostic accuracy of anteroposterior renal pelvic diameter (APD) measurement and the society for fetal urology (SFU) grading in neonatal ultrasonography (USG) for detecting uropathy in newborns having antenatal isolated hydronephrosis (IH), characterized by hydronephrosis without ureter and bladder abnormalities, and to study time to resolution and factors predicting resolution of insignificant hydronephrosis. Ninety-six healthy newborns (129 kidneys) with IH, who underwent USG at age 7-30 days and voiding cystourethrography (VCUG) in conjunction with diuretic renography (DR) if APD > 10 mm or SFU grade 3-4 in neonatal USG, and at least a 12-month follow-up were divided into significant and insignificant hydronephrosis using the combined data of sequential USG, VCUG, and DR as the reference standard. Areas under the receiver operating characteristic plots (95 % CI) were 0.86 (0.79-0.94) versus 0.81 (0.73-0.89); p = 0.08, and 87.6 versus 79.8 % of cases were correctly classified, for APD ≥ 16 mm versus SFU grade 4, respectively. Ureteropelvic junction obstruction (UPJO) was the most common uropathy diagnosed. Of 85 kidneys with insignificant hydronephrosis, 57 underwent spontaneous resolution. The resolution rates were 24, 40, and 68 % at age 6, 12, and 24 months, respectively. APD was the only independent factor predicting resolution with the hazard ratio of 0.83 (95 % CI 0.74-0.92; p = 0.001). In IH, neonatal USG was a useful diagnostic tool to detect uropathy, mainly UPJO. Further investigation should be recommended when APD ≥ 16 mm or SFU grade 4.

Homozygous 16p13.11 duplication associated with mild intellectual disability and urinary tract malformations in two siblings born from consanguineous parents.

PubMed

Houcinat, N; Llanas, B; Moutton, S; Toutain, J; Cailley, D; Arveiler, B; Combe, C; Lacombe, D; Rooryck, C

2015-11-01

The use of array-comparative genomic hybridization (array-CGH) in routine clinical work has allowed the identification of many new copy number variations (CNV). The 16p13.11 duplication has been implicated in various congenital anomalies and neurodevelopmental disorders, but it has also been identified in healthy individuals. We report a clinical observation of two brothers from related parents each carrying a homozygous 16p13.11 duplication. The propositus had mild intellectual disability and posterior urethral valves with chronic renal disease. His brother was considered a healthy child with only learning disabilities and poor academic performances. However, a routine medical examination at 25-years-old revealed a mild chronic renal disease and ureteropelvic junction obstruction. Furthermore, the father presented with a unilateral renal agenesis, thus it seemed that a "congenital anomalies of kidney and urinary tract" (CAKUT) phenotype segregated in this family. This may be related to the duplication, but we cannot exclude the involvement of additional genetic or non-genetic factors in the urological phenotype. Several cohort studies showed association between this chromosomal imbalance and different clinical manifestations, but rarely with CAKUT. The duplication reported here was similar to the larger one of 3.4 Mb previously described versus the more common of 1.6 Mb. It encompassed at least 11 known genes, including the five ohnologs previously identified. Our observation, in addition to expanding the clinical spectrum of the duplication provides further support to understanding the underlying pathogenic mechanism. © 2015 Wiley Periodicals, Inc.

Deformable three-dimensional model architecture for interactive augmented reality in minimally invasive surgery.

PubMed

Vemuri, Anant S; Wu, Jungle Chi-Hsiang; Liu, Kai-Che; Wu, Hurng-Sheng

2012-12-01

Surgical procedures have undergone considerable advancement during the last few decades. More recently, the availability of some imaging methods intraoperatively has added a new dimension to minimally invasive techniques. Augmented reality in surgery has been a topic of intense interest and research. Augmented reality involves usage of computer vision algorithms on video from endoscopic cameras or cameras mounted in the operating room to provide the surgeon additional information that he or she otherwise would have to recognize intuitively. One of the techniques combines a virtual preoperative model of the patient with the endoscope camera using natural or artificial landmarks to provide an augmented reality view in the operating room. The authors' approach is to provide this with the least number of changes to the operating room. Software architecture is presented to provide interactive adjustment in the registration of a three-dimensional (3D) model and endoscope video. Augmented reality including adrenalectomy, ureteropelvic junction obstruction, and retrocaval ureter and pancreas was used to perform 12 surgeries. The general feedback from the surgeons has been very positive not only in terms of deciding the positions for inserting points but also in knowing the least change in anatomy. The approach involves providing a deformable 3D model architecture and its application to the operating room. A 3D model with a deformable structure is needed to show the shape change of soft tissue during the surgery. The software architecture to provide interactive adjustment in registration of the 3D model and endoscope video with adjustability of every 3D model is presented.

Matched comparison of primary versus salvage laparoscopic pyeloplasty.

PubMed

Ambani, Sapan N; Yang, David Y; Wolf, J Stuart

2017-06-01

To compare our experience with salvage laparoscopic pyeloplasty, using a matched control set of primary laparoscopic pyeloplasty patients. We retrospectively reviewed patients who underwent laparoscopic pyeloplasty from 1996 to 2014 by a single surgeon. At least 12 months of follow-up was required. Salvage patients were matched 1:3 with primary patients. Matching was based on age ±5 years, body mass index (BMI) ±5, and type of pyeloplasty (dismembered vs. non-dismembered). Primary outcome was failure as defined as re-intervention following laparoscopic pyeloplasty (does not include temporary stenting without definitive retreatment). Of 128 laparoscopic pyeloplasty procedures, ten were salvage. These patients were matched to 26 patients who underwent a primary laparoscopic pyeloplasty in a 1:3 manner. One salvage pyeloplasty failed to match due to BMI, and the closest matches were made. Four salvage patients had one overlapping match, reducing the primary group to 26 patients. There were no differences in pre-, intra-, and postoperative variables between groups, except for operative time (salvage 247 min, primary 175 min, p = 0.03). With similar duration of radiologic and symptomatic follow-up, there was no significant difference in the rate of freedom from intervention. When matching for factors that could affect success, salvage laparoscopic pyeloplasty performed as well as primary pyeloplasty except for a longer operative time. In experienced hands, salvage laparoscopic pyeloplasty for ureteropelvic junction obstruction recurrence after prior pyeloplasty is a safe and effective procedure, and should be considered an excellent alternative to the more commonly recommended endopyelotomy.

Does antegrade JJ stenting affect the total operative time during laparoscopic pyeloplasty?

PubMed

Bolat, Mustafa Suat; Çınar, Önder; Akdeniz, Ekrem

2017-12-01

We aimed to show the effect of retrograde JJ stenting and intraoperative antegrade JJ stenting techniques on operative time in patients who underwent laparoscopic pyeloplasty. A total of 34 patients were retrospectively investigated (15 male and 19 female) with ureteropelvic junction obstruction. Of the patients stentized under local anesthesia preoperatively, as a part of surgery, 15 were retrogradely stentized at the beginning of the procedure (Group 1), and 19 were antegradely stentized during the procedure (Group 2). A transperitoneal dismembered pyeloplasty technique was performed in all patients. The two groups were retrospectively compared in terms of complications, the mean total operative time, and the mean stenting times. The mean ages of the patients were 31.5±15.5 and 33.2±15.5 years (p=0.09), and the mean body mass indexes were 25.8±5.6 and 26.2.3±8.4 kg/m 2 in Group 1 and Group 2, respectively. The mean total operative times were 128.9±38.9 min and 112.7±21.9 min (p=0.04); the mean stenting times were 12.6±5.4 min and 3.5±2.4 min (p=0.02); and the mean rates of catheterization-to-total surgery times were 0.1 and 0.03 (p=0.01) in Group 1 and 2, respectively. The mean hospital stays and the mean anastomosis times were similar between the two groups (p>0.05). Antegrade JJ stenting during laparoscopic pyeloplasty significantly decreased the total operative time.

Urinary biomarkers in hydronephrosis.

PubMed

Madsen, Mia Gebauer

2013-02-01

Hydronephrosis is diagnosed in 0.5-1% of all newborns, and ureteropelvic junction obstruction (UPJO) accounts for 35% of those cases. A urinary tract obstruction that occurs during early kidney development affects renal morphogenesis, maturation, and growth, and in the most severe cases, this will ultimately lead to progressive renal tubular atrophy and interstitial fibrosis with the loss of nephrons. The clinical management of these patients remains a controversial topic. The aim is to preserve renal function by identifying the 15-20% of children who require early surgical intervention from those for whom watchful waiting may be appropriate because of spontaneous resolving/stabilization without significant loss of renal function. Although the patients attend regular follow-ups, including repetitive blood tests, ultrasonographies, and the more invasive diuretic renograms, the surgeons still miss reliably biomarkers that could be used as predictors for renal parenchymal damage and decreased renal function, and thereby provide more clear indications for surgical intervention. The aim of this PhD thesis was to further elucidate the pathophysiology of obstructive nephropathy (study I) and to search for potential candidate biomarkers that may have a predictive and/or diagnostic value in the management of hydronephrosis (study II). Study I: Urine and kidney cytokine profiles in experimental unilateral acute and chronic hydronephrosis. To study the dynamics of the urinary secretion of cytokines after the release of unilateral ureteral obstruction, and to study whether the urinary concentrations of these compounds reliably reflects changes in the renal parenchyma. This was tested in 2 experimental rat models: an acute obstruction model and a chronic obstruction model. The acute obstruction model demonstrated significant differences in the renal levels of IL-1β, IL-6, TNF-α, and IL-10 in comparison with controls, and these differences were associated with similar differences in their urinary excretion. Such results were not obtained in the chronic obstruction model in which significant differences were only demonstrated in the urinary concentrations of IL-6. Study II: Candidate urinary biomarkers in hydronephrosis - a clinical study. To study the dynamics of the urinary excretion of selected potential biomarkers in children after the relief of UPJO, and to compare their findings with healthy controls. Twenty-eight children with UPJO were included in the study from 2007-2011 together with 13 healthy children. Pre-, peri- and post-operatively (1 year) urine samples were collected. The median age of the patients was 8.1 (3.5-14.5) years. Five proteins (EGF, IP-10, MCP-1, RANTES, and MIP-1α) were examined in study IIa, and 4 proteins (NGAL, CyC, βM-2, and OPN) were examined in study IIb. In brief, significantly increased urinary concentrations of EGF and MCP-1 were demonstrated in children with UPJO compared to controls, which was followed by a decline in the post-operative period to levels similar to the controls. This indicates that the urinary concentrations of EGF and MCP-1 are regulated as a response to the obstruction, suggesting that they may have a potential as urinary biomarkers in hydronephrosis. In general, urine from the obstructed kidney exhibited higher concentrations of the proteins compared to urine from the nonobstructed kidney. Furthermore, CyC, β-2M, and OPN were negatively correlated with age, and IP-10 and MCP-1 were negatively correlated with DRF. In conclusion, this PhD study confirmed increased concentrations of selected proteins in urine from kidneys suffering from obstruction. Interestingly, it was observed that some urinary proteins had an age-dependent excretion. Further investigations are required to test the ability of the examined proteins to identify an obstruction and reveal disease progression and, thereby, be useful clinical tools.

Clinical evaluation of double-pigtail stent in patients with upper urinary tract diseases: report of 2685 cases.

PubMed

Hao, Ping; Li, Weibing; Song, Caiping; Yan, Junan; Song, Bo; Li, Longkun

2008-01-01

To review the indications, procedures, complications, and related treatments of double pigtail stent (DPS) placement as an adjunct for some types of endoscopic and open urologic surgery. From July 1998 to December 2006, 2413 patients aged 8 to 81 years underwent stent placement (2685 total placements). The indications consisted of ureteroscopic lithotripsy (1984 cases), percutaneous nephrolithotomy (329 cases), ureteral incision to remove calculi (71 cases), extracorporeal shockwave lithotripsy for upper urinary tract calculi (145 cases), ureteropelvic junction obstruction (31 cases), ureterocystoneostomy (29 cases), benign ureteral stenosis (52 cases), extrinsic ureteral stenosis (16 cases), and iatrogenic ureteral trauma (28 cases). DPSs were inserted into the ureter by cystoscopy (115 stents), ureteroscopy (2052 stents), percutaneous nephrostomy (393 stents), or open surgery (125 stents), and were kept inside the body for 28 +/- 1.7 days (range 1-193 days). The mean follow-up period was 31 +/- 1.9 days (range 1-123 days). Three hundred sixty-five patients (19.6%) experienced one or more problems during the stenting procedure. The main complications were gross hematuria (385 cases), pain (101 cases), bladder irritation (105 cases), high fever (6 cases), encrustation (53 cases), stent migration (42 cases), and stenosis or restenosis (51 cases). Most of the complications were mild and tolerable, and all were immediately treated appropriately. However, 60 stents had to be removed: 29 for gross hematuria, 18 for pain, 7 for bladder irritation, and 6 for high fever. DPS is a safe and useful adjunct for both endoscopic and open procedures to treat upper urinary tract diseases. Most of the complications of DPS placement can be well managed.

The Difficult Ureter: Clinical and Radiographic Characteristics Associated With Upper Urinary Tract Access at the Time of Ureteroscopic Stone Treatment.

PubMed

Viers, Boyd R; Viers, Lyndsay D; Hull, Nathan C; Hanson, Theodore J; Mehta, Ramila A; Bergstralh, Eric J; Vrtiska, Terri J; Krambeck, Amy E

2015-11-01

To evaluate the association between clinicoradiographic features and need for prestenting (PS) because of inability of the ureter to accommodate the ureteroscope, or ureteral access sheath, at the time of stone treatment. From 2009 to 2013, 120 consecutive nonstented patients underwent ureteroscopic stone treatment with preoperative computerized tomography urogram. Acute stone events with obstruction or infection were excluded. Preoperative radiographic imaging underwent radiologist review. Clinicoradiographic features were characterized, and multivariable logistic regression models were used to identify covariates independently associated with need for PS. Of the 154 renal units treated, 25 (16%) required PS for failed primary access. PS ureters were less likely to have a history of prior ipsilateral ureteral stent (4% vs 31%) or surgery (8% vs 36%; P <.05). Radiographically, PS ureters had a narrower ureteropelvic junction (4 mm vs 5 mm) and were more likely to have <50% ureteral opacification on computerized tomography urogram (32% vs 9%; P <.05). On multivariable analysis, prior ipsilateral ureteral stent (odds ratio [OR] = 0.11) and stone surgery (OR = 0.15) reduced the need for PS; meanwhile, <50% ureteral opacification (OR = 4.41) was independently associated with an increased risk of access failure. We report a 16% incidence of access failure requiring PS at time of ureteroscopy. Clinically, there was an 89% and 85% risk reduction in the need for PS with prior history of ipsilateral ureteral stent or surgery. Radiographically, there was a 4.4-fold increased risk of PS with <50% ureteral opacification. Accordingly, our findings may assist in counseling and operative management of the difficult ureter. Copyright © 2015 Elsevier Inc. All rights reserved.

Transperitoneal laparoscopic pyeloplasty in children: does upper urinary tract anomalies affect surgical outcomes?

PubMed

Brunhara, João Arthur; Moscardi, Paulo Renato Marcelo; Mello, Marcos Figueiredo; Andrade, Hiury Silva; Carvalho, Paulo Afonso; Cezarino, Bruno Nicolino; Dénes, Francisco Tibor; Lopes, Roberto Iglesias

2018-01-01

To assess the feasibility and outcomes of laparoscopic pyeloplasty in children with complex ureteropelvic junction obstruction (UPJO) and compare to children with iso-lated UPJO without associated urinary tract abnormalities. Medical records of 82 consecutive children submitted to transperitoneal laparoscopic pyeloplasty in a 12-year period were reviewed. Eleven cases were con-sidered complex, consisting of atypical anatomy including horseshoe kidneys in 6 patients, pelvic kidneys in 3 patients, and a duplex collecting system in 2 patients. Patients were di-vided into 2 groups: normal anatomy (group 1) and complex cases (group 2). Demographics, perioperative data, outcomes and complications were recorded and analyzed. Mean age was 8.9 years (0.5-17.9) for group 1 and 5.9 years (0.5-17.2) for group 2, p=0.08. The median operative time was 200 minutes (180-230) for group 1 and 203 minutes (120-300) for group 2, p=0.15. Major complications (Clavien ≥3) were 4 (5.6%) in group 1 and 1 (6.3%) in group 2, p=0.52. No deaths or early postoperative complications such as: urinoma or urinary leakage or bleeding, occurred. The success rate for radiologic improvement and flank pain improvement was comparable between the two groups. Re-garding hydronephrosis, significant improvement was present in 62 patients (93.4%) of group 1 and 10 cases (90.9%) of group 2, p=0.99. The median hospital stay was 4 days (IQR 3-4) for group 1 and 4.8 days (IQR 3-6) for group 2, p=0.27. Transperitoneal laparoscopic pyeloplasty is feasible and effective for the management of UPJO associated with renal or urinary tract anomalies. Copyright® by the International Brazilian Journal of Urology.

[Unilateral renal agenesis. New arguments about the genetic relationship between kidney malformations and urolithiasis].

PubMed

Garcia Nieto, Victor; Huertes Díaz, Beatriz; Escribano Subias, Joaquin; Alarcón Alacio, Maria Teresa; Gonzalez Rodríguez, Juan David; Cabrera Sevilla, José Eugenio; Peralta Aros, Carolina; Luis Yanes, Maria Isabel

2016-11-01

In few previous works, it has been reported that hypercalciuria is associated with some types of CAKUT, namely ureteropelvic junction obstruction, vesicoureteral reflux or simple renal cysts. In addition, one higher prevalence of hypercalciuria and/or urolithiasis has been described in their family members compared to the general population. This study was carried out to find out whether children with unilateral renal agenesis (URA) have these features previously described in other CAKUT types. In a descriptive and multicenter study we studied the prevalence of hypercalciuria, hypocitraturia and urolithiasis in 67 children (43 males and 24 females) with URA and their families. The two metabolic anomalies that promote stone formation were observed in 26 children (38.8%), distributed as follows: hypercalciuria in 16, hypocitraturia in 9, and both hypercalciuria and hypocitraturia in 1. Eight children (11.9%) suffered renal colic during follow-up. Familial history of urolithiasis was found in 42/67 children (62.7%): in 12 of the first-degree relatives, in 15 of the second degree relatives and in 15 patients both in the first-degree as in their second degree relatives. In contrast, in historic control group, only in 28.1% of families at least one member had urolithiasis. Our results show that the prevalence of hypercalciuria and/or hypocitraturia is greater in pediatric patients with URA than in the general population. Likewise, the prevalence of urolithiasis in the families of these children is also higher than that in the general population. Copyright © 2015 Asociación Española de Pediatría. Publicado por Elsevier España, S.L.U. All rights reserved.

Chronically Elevated Levels of Short-Chain Fatty Acids Induce T Cell-Mediated Ureteritis and Hydronephrosis.

PubMed

Park, Jeongho; Goergen, Craig J; HogenEsch, Harm; Kim, Chang H

2016-03-01

Short-chain fatty acids (SCFAs) are major products of gut microbial fermentation and profoundly affect host health and disease. SCFAs generate IL-10(+) regulatory T cells, which may promote immune tolerance. However, SCFAs can also induce Th1 and Th17 cells upon immunological challenges and, therefore, also have the potential to induce inflammatory responses. Because of the seemingly paradoxical SCFA activities in regulating T cells, we investigated, in depth, the impact of elevated SCFA levels on T cells and tissue inflammation in mice. Orally administered SCFAs induced effector (Th1 and Th17) and regulatory T cells in ureter and kidney tissues, and they induced T cell-mediated ureteritis, leading to kidney hydronephrosis (hereafter called acetate-induced renal disease, or C2RD). Kidney hydronephrosis in C2RD was caused by ureteral obstruction, which was, in turn, induced by SCFA-induced inflammation in the ureteropelvic junction and proximal ureter. Oral administration of all major SCFAs, such as acetate, propionate, and butyrate, induced the disease. We found that C2RD development is dependent on mammalian target of rapamycin activation, T cell-derived inflammatory cytokines such as IFN-γ and IL-17, and gut microbiota. Young or male animals were more susceptible than old or female animals, respectively. However, SCFA receptor (GPR41 or GPR43) deficiency did not affect C2RD development. Thus, SCFAs, when systemically administered at levels higher than physiological levels, cause dysregulated T cell responses and tissue inflammation in the renal system. The results provide insights into the immunological and pathological effects of chronically elevated SCFAs. Copyright © 2016 by The American Association of Immunologists, Inc.

Small-incision access retroperitoneoscopic technique (SMART) pyeloplasty in adult patients: comparison of cosmetic and post-operative pain outcomes in a matched-pair analysis with standard retroperitoneoscopy: preliminary report.

PubMed

Pini, Giovannalberto; Goezen, Ali Serdar; Schulze, Michael; Hruza, Marcel; Klein, Jan; Rassweiler, Jens Jochen

2012-10-01

To present small-incision access retroperitoneoscopic technique pyeloplasty (SMARTp), a novel mini-laparoscopic approach for management of uretero-pelvic junction obstruction (UPJO) in adults including comparison with the standard retroperitoneoscopic technique (SRTp). In a non-randomised study, we matched 12 adult patients treated from August to November 2010 by SMARTp with 12 patients treated with SRTp from January to November 2010. Mini-laparoscopic retroperitoneal space was created with a home-made 6-mm balloon trocar. One 6-mm (for 5-mm 30° telescope) and two 3.5-mm trocars (for 3-mm working instrument) were used. SRTp was performed with 11- and 6-mm trocar. Primary endpoints included evaluation of cosmetic appearance and post-operative pain evaluated respectively by the patient and observer scar assessment scale (POSAS) and analogue visual scale (VAS). Secondary endpoints were comparison between operative and functional parameters. Cosmetic cumulative results were statistically significant in favour of SMARTp (POSAS: 37.9 vs. 52.4; P = 0.002). A better trend has been shown by post-operative pain (first to fourth day VAS), although not statistically significant (4.2 vs. 4.9, P = 0.891). No differences were recorded in terms of operative time, pre- and post-operative Hb difference, DJ-stent removal and resistive index (RI) improvement. The SMARTp group showed a faster drain removal (2.4 vs. 3.4 day, P = 0.004) and discharge (4.5 vs. 5.4 day P = 0.017). Preliminary data support SMARTp as safe procedures in experienced hands, providing better cosmetic results compared to SRTp. Further studies and clinical randomised trial performed in a larger population sample are requested.

Global minimally invasive pyeloplasty study in children: Results from the Pediatric Urology Expert Group of the European Association of Urology Young Academic Urologists working party.

PubMed

Silay, M S; Spinoit, A F; Undre, S; Fiala, V; Tandogdu, Z; Garmanova, T; Guttilla, A; Sancaktutar, A A; Haid, B; Waldert, M; Goyal, A; Serefoglu, E C; Baldassarre, E; Manzoni, G; Radford, A; Subramaniam, R; Cherian, A; Hoebeke, P; Jacobs, M; Rocco, B; Yuriy, R; Zattoni, Fabio; Kocvara, R; Koh, C J

2016-08-01

Minimally invasive pyeloplasty (MIP) for ureteropelvic junction (UPJ) obstruction in children has gained popularity over the past decade as an alternative to open surgery. The present study aimed to identify the factors affecting complication rates of MIP in children, and to compare the outcomes of laparoscopic (LP) and robotic-assisted laparoscopic pyeloplasty (RALP). The perioperative data of 783 pediatric patients (<18 years old) from 15 academic centers who underwent either LP or RALP with an Anderson Hynes dismembered pyeloplasty technique were retrospectively evaluated. Redo cases and patients with anatomic renal abnormalities were excluded. Demographics and operative data, including procedural factors, were collected. Complications were classified according to the Satava and modified Clavien systems. Failure was defined as any of the following: obstructive parameters on diuretic renal scintigraphy, decline in renal function, progressive hydronephrosis, or symptom relapse. Univariate and multivariate analysis were applied to identify factors affecting the complication rates. All parameters were compared between LP and RALP. A total of 575 children met the inclusion criteria. Laparoscopy, increased operative time, prolonged hospital stay, ureteral stenting technique, and time required for stenting were factors influencing complication rates on univariate analysis. None of those factors remained significant on multivariate analysis. Mean follow-up was 12.8 ± 9.8 months for RALP and 45.2 ± 33.8 months for LP (P = 0.001). Hospital stay and time for stenting were shorter for robotic pyeloplasty (P < 0.05 for both). Success rates were similar between RALP and LP (99.5% vs 97.3%, P = 0.11). The intraoperative complication rate was comparable between RALP and LP (3.8% vs 7.4%, P = 0.06). However, the postoperative complication rate was significantly higher in the LP group (3.2% for RALP and 7.7% for LP, P = 0.02). All complications were of no greater severity than Satava Grade IIa and Clavien Grade IIIb. This was the largest multicenter series of LP and RALP in the pediatric population. Limitations of the study included the retrospective design and lack of surgical experience as a confounder. Both minimally invasive approaches that were studied were safe and highly effective in treating UPJ obstruction in children in many centers globally. However, shorter hospitalization time and lower postoperative complication rates with RALP were noted. The aims of the study were met. Copyright © 2016 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

Free-beam and contact laser soft-tissue ablation in urology.

PubMed

Tan, Andrew H H; Gilling, Peter J

2003-10-01

The ablation of tissue by laser has several applications in urology. Most of the published research has been concerned with the treatment of benign prostatic hyperplasia (BPH). Other applications studied include superficial upper- and lower-tract transitional-cell carcinoma, urethral and ureteral strictures, ureteropelvic junction stenosis, and posterior urethral valves. The attraction of laser ablation for the treatment of BPH lies with the decreased morbidity in comparison with standard transurethral electrocautery resection of the prostate and the ability to remove tissue immediately and therefore allow a more rapid progression to catheter removal and early voiding. The three main laser wavelengths used in urology for tissue ablation are the neodymium:yttrium-aluminum-garnet when used with contact tips or high-density power settings, the potassium-titanyl-phosphate, and the holmium:YAG. This article reviews the published literature on the use of these laser wavelengths in soft-tissue ablation, focusing on the treatment of BPH.

Detailed evaluation of the upper urinary tract in patients with prune belly syndrome using magnetic resonance urography.

PubMed

Garcia-Roig, M L; Grattan-Smith, J D; Arlen, A M; Smith, E A; Kirsch, A J

2016-04-01

Magnetic resonance urography (MRU) has proven to be useful in the setting of complex urologic anatomy. Prune belly syndrome (PBS) patients are known to have malformed and highly variable urinary tract anatomy due to significant dilation and renal dysplasia. To further characterize the renal and ureteral anatomy and renal function in patients with PBS via MRU. Children with PBS undergoing MRU (2006-2011) were identified. Studies were performed to evaluate severe hydronephrosis in all patients. Demographics, previous imaging, and MRU findings were collected. A single radiologist reviewed all studies. MRU was performed on 13 boys, with a median age of 29.3 months (IQR 6-97). Two patients underwent >1 study for ureteropelvic junction obstruction (UPJ obstruction) and calyceal diverticulum with a solitary kidney, respectively. Hydroureteronephrosis (HUN) was identified in 12 boys (92%), while one (8%) did not have ureteral dilation. All patients demonstrated morphologic abnormalities beyond HUN as follows: five (38%) renal dysplasia; five (38%) scarring; four (31%) calyceal diverticula; and three (23%) thickened bladder. The median renal transit time (RTT) was 6 min (IQR 3.5-10.5), and >8 min (range 8.5-35) in six patients; one patient was ultimately diagnosed with obstruction. The mean serum creatinine was 0.5 ± 0.3 mg/dl. This summary figure is a coronal excretory phase T1 MRU image demonstrating absence of well-defined calyces and a 5-cm calyceal diverticulum (white arrow). This study reports significant anatomic and functional findings on MRU that were not readily apparent when using standard imaging for children with PBS. The high-resolution images and functional data obtained with MRU allowed for visualization of calyceal diverticula and abnormal renal pelvic anatomy not previously described in PBS. In addition, renal dysplasia could be identified with MRU, which is badly characterized in the PBS population outside of renal biopsy studies. Potential limitations of the study included its nature as a small retrospective case series, which limited the ability to compare imaging modalities. Imaging modalities were based on individual clinical needs; therefore, comparison with diuretic renal scintigraphy was limited. MRU provided anatomic and functional details of the urinary tract in children with PBS that allowed for characterization of new renal anatomic abnormalities, including the incidence of calyceal diverticula and renal dysplasia, which have not been previously described. While renal scarring, dysplasia and calyceal diverticula were easily discerned on MRU in ten patients, their clinical significance requires longer follow-up in a larger patient population. Copyright © 2015 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

Robot-assisted Surgery for Benign Ureteral Strictures: Experience and Outcomes from Four Tertiary Care Institutions.

PubMed

Buffi, Nicolò Maria; Lughezzani, Giovanni; Hurle, Rodolfo; Lazzeri, Massimo; Taverna, Gianluigi; Bozzini, Giorgio; Bertolo, Riccardo; Checcucci, Enrico; Porpiglia, Francesco; Fossati, Nicola; Gandaglia, Giorgio; Larcher, Alessandro; Suardi, Nazareno; Montorsi, Francesco; Lista, Giuliana; Guazzoni, Giorgio; Mottrie, Alexandre

2017-06-01

Minimally invasive treatment of benign ureteral strictures is still challenging because of its technical complexity. In this context, robot-assisted surgery may overcome the limits of the laparoscopic approach. To evaluate outcomes for robotic ureteral repair in a multi-institutional cohort of patients treated for ureteropelvic junction obstruction and ureteral stricture (US) at four tertiary referral centres. This retrospective study reports data for 183 patients treated with standard robot-assisted pyeloplasty (PYP) and robotic uretero-ureterostomy (UUY) at four high-volume centres from January 2006 to September 2014. Robotic PYP and robot-assisted UUY were performed according to previously reported surgical techniques. Preoperative, intraoperative, and postoperative variables and outcomes were assessed. A descriptive statistical analysis was performed. No robot-assisted UUY cases required surgical conversion, while 2.8% of PYP cases were not completed robotically. The median operative time was 120 and 150min for robot-assisted PYP and robot-assisted UUY, respectively. No intraoperative complications were reported. The overall complication rate for all procedures was 11% (n=20) and complications were mostly of low grade. The high-grade complication rate was 2.2% (n=4). At median follow-up of 24 mo, the overall success rate was >90% for both procedures. The study limitations include its retrospective nature and the heterogeneity of the study population. Robotic surgery for benign US is safe and effective, with limited risk of high-grade complications and good intermediate-term results. In this study we review the use of robotic surgery at four different tertiary care centres in the treatment of patients affected by benign ureteral strictures. Our results demonstrate that robotic surgery is a safe alternative to the standard open approach in the treatment of ureteral strictures. Copyright © 2016 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Povidone iodine sclerotherapy for treatment of idiopathic renal hematuria in two dogs.

PubMed

Adelman, Lauren B; Bartges, Joseph; Whittemore, Jacqueline C

2017-01-15

CASE DESCRIPTION A 6-year-old spayed female Great Pyrenees (dog 1) and a 2-year-old spayed female German Shepherd Dog (dog 2) were evaluated because of gross hematuria of 5 and 2 months' duration, respectively. CLINICAL FINDINGS In both dogs, coagulation times were within reference limits, results of aerobic bacterial culture of urine samples were negative, echogenic debris could be seen within the urinary bladder ultrasonographically, and hematuric urine could be seen exiting the right ureterovesicular junction, with grossly normal urine exiting the left ureterovesicular junction, during cystoscopy. A diagnosis of idiopathic renal hematuria was made in both dogs. TREATMENT AND OUTCOME Both dogs underwent retrograde ureteropyelography, unilateral povidone iodine sclerotherapy, and ureteral stent placement. The right ureter was occluded with a ureteropelvic junction balloon catheter, and a 5% povidone iodine solution was infused into the renal pelvis 3 times. A double-pigtail ureteral stent was then placed. Both dogs recovered without complications, with cessation of gross hematuria within 12 hours. Cystoscopic removal of the ureteral stent was performed in dog 1 after 4 months; at that time, the urine sediment contained 5 to 10 RBCs/hpf. In dog 2, urine sediment contained 50 to 75 RBCs/hpf 2 weeks after sclerotherapy, with continued resolution of gross hematuria 8 weeks after sclerotherapy. The owners declined removal of the stent in dog 2. CLINICAL RELEVANCE Findings suggested that povidone iodine sclerotherapy may be an effective renal-sparing treatment for idiopathic renal hematuria in dogs. Further evaluation with longer follow-up times is warranted.

Preliminary Assessment of a New Antireflux Ureteral Stent Design in Swine Model.

PubMed

Soria, Federico; Morcillo, Esther; Serrano, Alvaro; Rioja, Jorge; Budia, Alberto; Moreno, Jesús; Sanchez-Margallo, Francisco M

2015-08-01

To assess a new antireflux ureteral stent in animal model. The design expects to reduce morbidity associated with JJ ureteral stents. Twelve pigs were used in this study. The study began with a nephrosonographic assessment and excretory urography. Afterward, measurement of the internal diameter of both ureteropelvic junctions (UPJ) by retrograde ureteropyelography was performed. A 3 Fr (ARS group) antireflux ureteral stent was placed in the right kidney and a JJ 4 Fr (JJ group) stent was placed in the left. Follow-ups were performed at 3-6 weeks; both stents were removed at 6 weeks. The final follow-up was completed at 5 months. This includes the above-mentioned diagnostic methods and an anatomopathological study. There were no significant differences in UPJ diameter evolution between groups. During renal damage assessment, significant differences at 3 and 6 weeks were found, renal dilation being larger in JJ group. The JJ group shows a higher degree of vesicoureteral reflux at 3 and 6 weeks. After assessment of ureteral orifice, significant differences between groups were found at 3 weeks, 6 weeks, and 5 months, damage being more severe in the JJ group. After anatomopathological assessment, no statistical significance at UPJ was observed. However, statistical significance was found at ureterovesical junction, damage being more severe in the JJ group. The antireflux ureteral stent design dilates the upper urinary tract without affecting ureterovesical junction, and consequently reduces morbidity associated with JJ ureteral stents. Therefore, its patient tolerance will possibly be better than that to existent designs. Copyright © 2015 Elsevier Inc. All rights reserved.

Functional and Anatomic Esophagogastic Junction Outflow Obstruction: Manometry, Timed Barium Esophagram Findings, and Treatment Outcomes.

PubMed

Clayton, Steven B; Patel, Rupal; Richter, Joel E

2016-06-01

Little is known about the clinical features, radiology and manometry findings, and treatment outcomes of patients with functional and mechanical esophagogastic junction outflow obstruction (EGJOO). Between November 2011 and February 2015, a total of 1443 high-resolution manometries were reviewed and 49 patients (3.4%) met the manometric criteria for EGJOO. Then, we performed a retrospective chart review, collecting data from manometric studies, timed barium esophagram findings (TBEs), endoscopic reports, and clinical records. Twenty-seven patients had functional EGJOO and 22 patients had an anatomic esophageal obstruction. Common causes of anatomic EGJOO included strictures (36% of patients) and hiatal hernias (31% of patients). There were no differences between groups in manometric or radiographic metrics. Each group had increased basal lower esophageal sphincter and intrabolus pressures, compared with individuals without EGJOO, and most patients had abnormal findings on TBE analysis. Two patients with functional EGJOO progressed to type 3 achalasia. We conclude that patients diagnosed with EGJOO based on manometry findings can have anatomic obstruction or functional EGJOO; high-resolution manometry and TBE do not distinguish between disease causes. Copyright © 2016 AGA Institute. Published by Elsevier Inc. All rights reserved.

Is the gravity effect of radiographic anatomic features enough to justify stone clearance or fragments retention following extracorporeal shock wave lithotripsy (SWL).

PubMed

Mustafa, Mahmoud

2012-08-01

We determined whether the gravity effect of radiographic anatomic features on the preoperative urography (IVP) are enough to predict fragments clearance after shock wave lithotripsy (SWL). A Total of 282 patients with mean age 45.8 ± 13.2 years (189 male, 93 female), who underwent SWL due to renal calculi between October 2005 and August 2009 were enrolled. The mean calculi load was 155.72 ± 127.66 mm². The patients were stratified into three groups: patients with pelvis calculi (group 1); patients with upper or middle pole calculi (group 2) and patients with lower pole calculi (group 3). Three angles on the pretreatment IVP were measured: the inner angle between the axis of the lower pole infundibular and ureteropelvic axis (angle I); the inner angle between the lower pole infundibular axis and main axis of pelvis-ureteropelvic (UP) junction point (angle II) and the inner angle between the lower pole infundibular axis and perpendicular line (angle III). Multivariate analysis was used to define the significant predictors of stone clearance. The overall success rate was 85.81%. All angles, sessions number, shock waves number and stone burden were significant predictors of success in patients in group 1. However, in group 2 only angle II and in group 3 angles I and II had significant effect on stone clearance. Radiographic anatomic features have significant role in determining the stone-free rate following satisfactory fragmentation of renal stones with SWL. The measurement of infundibulopelvic angle in different manner helps to predict the stone-free status in patients with renal calculi located not only in lower pole, but also in renal pelvis and upper or middle pole. Gravity effect is not enough to justify the significant influence of the radiographic anatomic features on the stone clearance and fragments retention after SWL.

Genetic locus on chromosome 6p for multicystic renal dysplasia, pelvi-ureteral junction stenosis, and vesicoureteral reflux

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

Devriendt, K.; Fryns, J.P.

1995-11-20

Robson et al. suggest that renal agenesis, multicystic renal dysplasia (MRD), and uretero-pelvic junction (PUJ) stenosis are pathogenetically related. They proposed a vascular disruption as the cause, with the variable severity of the disorder related to the timing of the abnormal blood supply to the ureteric bud. Alternatively, there exists convincing evidence of a genetic cause transmitted as an autosomal dominant disorder with variable expression, and with a candidate gene localized on chromosome arm 6p. Combinations of these urological malformations occur in the same individual or in different relatives in the same family. In several families with PUJ-stenosis, linkage withmore » the HLA-locus on 6p has been demonstrated. Furthermore, we recently described a patient with a de novo reciprocal translocation involving the same region on 6p in a patient with bilateral multicystic renal dysplasia. Most disease-associated reciprocal translocations appear to have a breakpoint within a candidate gene: therefore, it is reasonable to hypothesize that the breakpoint on 6p in this patient resides within a gene causing MRD. This suggests that mutations in the same gene may lead either to PUJ-stenosis or, when the stenosis is complete, to MRD. A translocation is expected to result in a complete disruption of the gene, and this could explain the severe clinical expression of bilateral MRD. Less severe mutations in the same gene, associated with a partially conserved gene function, could lead to PUJ-stenosis. 11 refs.« less

Pelviureteric obstruction in children: conventional pyeloplasty is superior to endo-urology.

PubMed

Ahmed, S; Crankson, S; Sripathi, V

1998-09-01

Hydronephrosis secondary to pelviureteric junction (PUJ) obstruction is common in infancy and childhood. Pyeloplasty has until recently been the accepted method of management, but alternative endo-urological techniques have evolved in the last decade. Published results of conventional pyeloplasty for primary PUJ obstruction in children were compared with published results of endo-urological procedures. Sixty-six pyeloplasties were performed in 61 children in a 6-year period. During a similar period, 63 primary endo-urological procedures were reported in the literature. The success rate after pyeloplasty was 95.5% compared with 65% after endo-urology. Conventional pyeloplasty is superior to endo-urology and should remain the gold standard for the treatment of primary PUJ obstruction in children.

In utero oxcarbazepine and a withdrawal syndrome, anomalies, and hyponatremia.

PubMed

Rolnitsky, Asaph; Merlob, Paul; Klinger, Gil

2013-06-01

Oxcarbazepine is an antiepileptic agent that has been used during pregnancy, although its safety during pregnancy has not been sufficiently established. This article presents an infant born with renal and cardiac malformations who developed a withdrawal syndrome and hyponatremia following in utero exposure to oxcarbazepine. The infant was born at 35 weeks' gestation by urgent cesarean section to a mother in status epilepticus who had been treated with oxcarbazepine throughout her pregnancy. Evaluation for congenital anomalies identified mild aortic stenosis, a bicuspid aortic valve, patent foramen ovale, patent ductus arteriosus, and severe left hydronephrosis due to left ureteropelvic junction stenosis. On the third day of life the infant developed clinical signs of a withdrawal syndrome, which peaked on day 7 and resolved by day 12. Transient hyponatremia resolved by day 8 of life. Follow-up showed normal development at 15 months. The association of a withdrawal syndrome with oxcarbazepine exposure has not been previously reported. The hyponatremia is consistent with adult reports. The possible association of oxcarbazepine with renal and cardiac malformations requires further confirmation. Copyright © 2013 Elsevier Inc. All rights reserved.

Associations of Initial Society for Fetal Urology Grades and Urinary Tract Dilatation Risk Groups with Clinical Outcomes in Patients with Isolated Prenatal Hydronephrosis.

PubMed

Braga, Luis H; McGrath, Melissa; Farrokhyar, Forough; Jegatheeswaran, Kizanee; Lorenzo, Armando J

2017-03-01

There are limited comparative data on the predictive value of the 2 most commonly used classification systems, that is SFU (Society for Fetal Urology) hydronephrosis grades and urinary tract dilatation risk groups, in regard to the future risk of surgical intervention and the development of febrile urinary tract infection. We explored this topic in infants with isolated hydronephrosis. After screening 938 patients with prenatal hydronephrosis from 2009 to 2016 we selected 322 patients with ureteropelvic junction obstruction-like hydronephrosis for study. Hydronephrosis grades were prospectively collected at baseline, surgery and last followup. Gender, circumcision status, antibiotic prophylaxis and renal pelvis anteroposterior diameter were captured. The primary outcome was pyeloplasty and the development of febrile urinary tract infection. Comparative analyses between SFU grades/urinary tract dilatation groups and the primary outcome were performed with the Fisher exact and log rank tests. Mean ± SD age at presentation was 3.3 ± 2.6 months and mean followup was 22 ± 19 months. Pyeloplasty was performed in 32% of patients with SFU III/IV vs 31% with urinary tract dilatation 2/3. The rate of febrile urinary tract infection in patients with SFU III/IV was similar to that in those with urinary tract dilatation group 2/3 (8% vs 10%). Children with SFU III/IV showed a significantly higher rate of surgery than those with SFU I/II (32% vs 2%, p <0.01). Similar findings were seen when using urinary tract dilatation groups to compare patients at low risk (1) vs moderate/high risk (2/3). Both grading systems equally allowed for proper risk stratification and prediction of clinical outcomes based on baseline ultrasound. They correctly separated most infants who underwent surgery or in whom febrile urinary tract infection developed from those who could be treated nonsurgically. Use of the new urinary tract dilatation classification should not affect how families of children with isolated hydronephrosis are counseled regarding surgical intervention and the risk of febrile urinary tract infection. Copyright © 2017 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Retroperitoneal laparoscopic pyeloplasty in children: long-term outcome and critical analysis of 10-year experience in a teaching center.

PubMed

Blanc, Thomas; Muller, Cecile; Abdoul, Hendy; Peev, Stoyen; Paye-Jaouen, Annabel; Peycelon, Matthieu; Carricaburu, Elisabeth; El-Ghoneimi, Alaa

2013-03-01

Laparoscopic pyeloplasty in children remains controversial and is not included in most pediatric urology centers because of technical difficulties and lack of long-term results. To critically analyze our 10-yr experience with the retroperitoneal approach (RA), with a particular interest on the impact of the learning curve in a teaching center. Patients who underwent pyeloplasty between 1999 and 2010 at our institution were reviewed (n=390). The diagnosis of ureteropelvic junction obstruction was confirmed by ultrasound and technetium Tc 99m mercaptoacetyltriglycine-3 renal scan or magnetic resonance imaging; the same criteria were used to evaluate the outcome. The lateral RA was selected in children >1 yr of age without abnormal migration or fusion of the kidney (n=104). Dismembered pyeloplasty and anastomosis were performed using running monofilament 5-0 or 6-0 absorbable suture. All were drained by double-J stent except 20 cases drained by external transanastomotic stent. We assessed intra- and postoperative morbidity and analyzed the teaching of technique and learning curve. Data are expressed as medians and interquartile range (25th, 75th percentiles) for quantitative variables. Median age was 6.2 yr (2.2-10.3). Thirty-three patients had crossing vessels. Median operative time was 185 min (160-235). Median hospital stay was 2 d (1-2). Redo pyeloplasty was needed in only two children (2%). Median follow-up was 2.1 yr (1.4-4.1). Operative time was <3 h after 35 cases. After 30 cases performed by the same surgeon, standardization of the technique was feasible, which helped in the teaching process because 50% of the final 30 cases were done by trainees. Retroperitoneal dismembered laparoscopic pyeloplasty is a safe, reliable, and efficient procedure with an excellent outcome in selected children according to their indications and age, and the experience of the surgical team. Even if the transmission to trainees is successful, it is still a long learning process and remains a challenging task for a teaching center. Copyright © 2012. Published by Elsevier B.V.

Revised guidelines on management of antenatal hydronephrosis.

PubMed

Sinha, Aditi; Bagga, Arvind; Krishna, Anurag; Bajpai, Minu; Srinivas, M; Uppal, Rajesh; Agarwal, Indira

2013-02-01

Widespread antenatal screening has resulted in increased detection of anomalies of the kidneys and urinary tract. The present guidelines update the recommendations published in 2000. Antenatal hydronephrosis (ANH) is transient and resolves by the third trimester in almost one-half cases. The presence of oligohydramnios and additional renal or extrarenal anomalies suggests significant pathology. All patients with ANH should undergo postnatal ultrasonography; the intensity of subsequent evaluation depends on anteroposterior diameter (APD) of the renal pelvis and/or Society for Fetal Urology (SFU) grading. Patients with postnatal APD exceeding 10 mm and/or SFU grade 3-4 should be screened for upper or lower urinary tract obstruction and vesicoureteric reflux. Infants with vesicoureteric reflux should receive antibiotic prophylaxis through the first year of life, and their parents counseled regarding the risk of urinary tract infections. The management of patients with pelviureteric junction or vesicoureteric junction obstruction depends on clinical features and results of sequential ultrasonography and radionuclide renography. Surgery is considered in patients with increasing renal pelvic APD and/or an obstructed renogram with differential renal function <35-40% or its subsequent decline. Further studies are necessary to clarify the role of prenatal intervention, frequency of follow up investigations and indications for surgery in these patients.

Revised guidelines on management of antenatal hydronephrosis

PubMed Central

Sinha, A.; Bagga, A.; Krishna, A; Bajpai, M.; Srinivas, M.; Uppal, R.; Agarwal, I.

2013-01-01

Widespread antenatal screening has resulted in increased detection of anomalies of the kidneys and urinary tract. The present guidelines update the recommendations published in 2000. Antenatal hydronephrosis (ANH) is transient and resolves by the third trimester in almost one-half cases. The presence of oligohydramnios and additional renal or extrarenal anomalies suggests significant pathology. All patients with ANH should undergo postnatal ultrasonography; the intensity of subsequent evaluation depends on anteroposterior diameter (APD) of the renal pelvis and/or Society for Fetal Urology (SFU) grading. Patients with postnatal APD exceeding 10 mm and/or SFU grade 3-4 should be screened for upper or lower urinary tract obstruction and vesicoureteric reflux (VUR). Infants with VUR should receive antibiotic prophylaxis through the first year of life, and their parents counseled regarding the risk of urinary tract infections. The management of patients with pelviureteric junction or vesicoureteric junction obstruction depends on clinical features and results of sequential ultrasonography and radionuclide renography. Surgery is considered in patients with increasing renal pelvic APD and/or an obstructed renogram with differential renal function <35-40% or its subsequent decline. Further studies are necessary to clarify the role of prenatal intervention, frequency of follow-up investigations and indications for surgery in these patients. PMID:23716913

Ileocecocolic strictures in two captive cheetahs (Acinonyx jubatus jubatus).

PubMed

Travis, Erika K; Duncan, Mary; Weber, Martha; Adkesson, Michael J; Junge, Randall E

2007-12-01

Intestinal strictures were diagnosed in two captive cheetahs (Acinonyx jubatus jubatus). The cheetahs presented with lethargy, anorexia, diarrhea, and weight loss. The first cheetah had a stricture of the ileocecocolic junction diagnosed at necropsy. The second had an ileocecocolic stricture causing obstruction that was diagnosed at surgery. After resection and anastomosis, the cheetah recovered well. The etiology of the strictures remains undetermined. Intestinal stricture, particularly of the ileocecocolic junction, should be considered as a differential diagnosis for cheetahs with nonspecific gastrointestinal signs.

Economic analysis of continuous antibiotic prophylaxis for prevention of urinary tract infections in infants with high-grade hydronephrosis.

PubMed

Tu, H Y V; Pemberton, J; Lorenzo, A J; Braga, L H

2015-10-01

For infants with hydronephrosis, continuous antibiotic prophylaxis (CAP) may reduce urinary tract infections (UTIs); however, its value remains controversial. Recent studies have suggested that neonates with severe obstructive hydronephrosis are at an increased risk of UTIs, and support the use of CAP. Other studies have demonstrated the negligible risk for UTIs in the setting of suspected ureteropelvic junction obstruction and have highlighted the limited role of CAP in hydronephrosis. Furthermore, economic studies in this patient population have been sparse. This study aimed to evaluate whether the use of CAP is an efficient expenditure for preventing UTIs in children with high-grade hydronephrosis within the first 2 years of life. A decision model was used to estimate expected costs, clinical outcomes and quality-adjusted life years (QALYs) of CAP versus no CAP (Fig. 1). Cost data were collected from provincial databases and converted to 2013 Canadian dollars (CAD). Estimates of risks and health utility values were extracted from published literature. The analysis was performed over a time horizon of 2 years. One-way and probabilistic sensitivity analyses were carried out to assess uncertainty and robustness. Overall, CAP use was less costly and provided a minimal increase in health utility when compared to no CAP (Table). The mean cost over two years for CAP and no CAP was CAD$1571.19 and CAD$1956.44, respectively. The use of CAP reduced outpatient-managed UTIs by 0.21 infections and UTIs requiring hospitalization by 0.04 infections over 2 years. Cost-utility analysis revealed an increase of 0.0001 QALYs/year when using CAP. The CAP arm exhibited strong dominance over no CAP in all sensitivity analyses and across all willingness-to-pay thresholds. The use of CAP exhibited strong dominance in the economic evaluation, despite a small gain of 0.0001 QALYs/year. Whether this slight gain is clinically significant remains to be determined. However, small QALY gains have been reported in other pediatric economic evaluations. Strengths of this study included the use of data from a recent systematic review and meta-analysis, in addition to a comprehensive probabilistic sensitivity analysis. Limitations of this study included the use of estimates for UTI probabilities in the second year of life and health utility values, given that they were lacking in the literature. Spontaneous resolution of hydronephrosis and surgical management were also not implemented in this model. To prevent UTIs within the first 2 years of life in infants with high-grade hydronephrosis, this probabilistic model has shown that CAP use is a prudent expenditure of healthcare resources when compared to no CAP. Copyright © 2015 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

Antegrade jj stenting after percutaneous renal procedures: The 'pull and push' technique.

PubMed

Ratkal, Jaideep M; Sharma, Elias

2015-06-01

A JJ stent is inserted antegradely after percutaneous renal procedures like percutaneous nephrolithotomy (PCNL) for renal calculus disease, and for endopyelotomy for pelvi-ureteric junction obstruction. We describe a technique for antegrade stent insertion after PCNL.

Hydronephrosis is associated with elevated plasmin in urine in pediatric patients and rats and changes in NCC and γ-ENaC abundance in rat kidney.

PubMed

Zachar, Rikke; Al-Mashhadi, Ammar; Dimke, Henrik; Svenningsen, Per; Jensen, Boye L; Carlström, Mattias

2018-05-16

Obstruction of urine flow at the level of the pelvo-ureteric junction (UPJO) and subsequent development of hydronephrosis is one of the most common congenital renal malformations. UPJO is associated with development of salt-sensitive hypertension, which is set by the obstructed kidney, and with a stimulated renin-angiotensin-aldosterone system (RAAS) in rodent models. This study aimed at investigating the hypothesis that i) in pediatric patients with UPJO the RAAS is activated prior to surgical relief of the obstruction; ii) in rats with UPJO the RAAS activation is reflected by increased abundance of renal aldosterone-stimulated Na+ transporters; and iii) the injured UPJO kidney allows aberrant filtration of plasminogen leading to proteolytic activation of the epithelial sodium channel gamma subunit (γ-ENaC). Hydronephrosis due to UPJO in pediatric patients and rats was associated with increased urinary plasminogen/creatinine ratio. In pediatric patients, plasma renin, angiotensin II, urine and plasma aldosterone and urine soluble pro-renin receptor did not differ significantly before and after surgery, or compared with controls. Increased plasmin/plasminogen ratio was seen in UPJO rats. Intact γ-ENaC abundance was not changed in UPJO kidney while low-molecular cleavage product abundance increased. The Na-Cl cotransporter (NCC) displayed significantly lower abundance in the UPJO kidney compared to the non-obstructed contralateral kidney. The Na-K-ATPase alpha-subunit was unaltered. Treatment with an angiotensin-converting enzyme inhibitor (8 days, captopril) significantly lowered blood pressure in UPJO rats. It is concluded that the RAAS contributes to hypertension following partial obstruction of urine flow at the pelvo-ureteric junction with potential contribution from proteolytic activation of ENaC.

Antegrade jj stenting after percutaneous renal procedures: The ‘pull and push’ technique

PubMed Central

Ratkal, Jaideep M.; Sharma, Elias

2014-01-01

A JJ stent is inserted antegradely after percutaneous renal procedures like percutaneous nephrolithotomy (PCNL) for renal calculus disease, and for endopyelotomy for pelvi-ureteric junction obstruction. We describe a technique for antegrade stent insertion after PCNL. PMID:26413327

[Intraoperative ultrasonography, dissection with ultra-shears and trans-cystic choledochoscopy during laparoscopic approach in obstructive lithiasis icterus case].

PubMed

Alecu, L; Corodeanu, G; Costan, I; Lungu, C; Staicu, A

2001-01-01

The authors present the case of a 48 years old male with lithiasis obstructive icterus who was operated by laparoscopic transcystic approach with choledochoscopy. This minimally invasive technique was very spectacular trough the using of laparoscopic ultrasonography, dissection with Ultra-Shears device and transcystic choledochoscopy. Careful watching of abdominal laparoscopic view and transcystic choledochoscopic view is the particularity of laparoscopic transcystic management of choledocholithiasis. This metod don't let us to explore the biliary tract before the junction between common bile duct and cystic duct.

Idiopathic gastroesophageal reflux disease in an adult horse.

PubMed

Baker, Shannon J; Johnson, Philip J; David, Andrew; Cook, Cristi Reeves

2004-06-15

Chronic gastroesophageal reflux disease was diagnosed in a 22-year-old female Tennessee Walking Horse that had signs of bruxism and ptyalism. Esophageal ulceration was detected via endoscopy. Compared with the damage to the proximal portions of the esophagus, the severity of the ulceration increased toward the gastroesophageal junction. Esophageal ulceration attributable to chronic gastric acid reflux is usually secondary to pyloric outflow obstruction in horses. In the horse of this report, there was no evidence of either a chronic pyloric or duodenal obstruction that could have resulted in esophageal ulceration. Esophageal ulceration in this horse was attributed to gastroesophageal reflux disease, a common condition in humans in which the underlying abnormality is functional incompetence of the gastroesophageal junction. Treatment is directed at decreasing gastric acidity and protecting the ulcerated mucosa. In the horse of this report, treatment was unsuccessful and the horse was euthanatized; a physical cause of gastroesophageal reflux disease was not identified during an extensive postmortem examination.

The Fate of Nephrons in Congenital Obstructive Nephropathy: Adult Recovery is Limited by Nephron Number Despite Early Release of Obstruction.

PubMed

Sergio, Maria; Galarreta, Carolina I; Thornhill, Barbara A; Forbes, Michael S; Chevalier, Robert L

2015-11-01

Urinary tract obstruction and reduced nephron number often occur together as a result of maldevelopment of the kidneys and the urinary tract. We determined the role of nephron number on adaptation of the remaining nephrons of mice subjected to neonatal partial unilateral ureteral obstruction followed through adulthood. Wild-type and Os/+ mice (the latter with 50% fewer nephrons) underwent sham operation or partial unilateral ureteral obstruction in the first 2 days of life. Additional mice underwent release of unilateral ureteral obstruction at 7 days. All kidneys were harvested at 3 weeks (weaning) or 6 weeks (adulthood). Glomerular number and area, glomerulotubular junction integrity, proximal tubular volume fraction and interstitial fibrosis were measured by histomorphometry. In the obstructed kidney unilateral ureteral obstruction caused additional nephron loss in Os/+ but not in wild-type mice. Glomerular growth from 3 to 6 weeks was impaired by ipsilateral obstruction and not preserved by release in wild-type or Os/+ mice. Proximal tubular growth was impaired and interstitial collagen was increased by ipsilateral obstruction in all mice. These conditions were attenuated by release of unilateral ureteral obstruction in wild-type mice but were not restored in Os/+ mice. Unilateral ureteral obstruction increased interstitial collagen in the contralateral kidney while release of obstruction enhanced tubular growth and reduced interstitial collagen. Unilateral ureteral obstruction in early postnatal development impairs adaptation to reduced nephron number and induces additional nephron loss despite release of obstruction. Premature and low birth weight infants with congenital obstructive nephropathy are likely at increased risk for progression of chronic kidney disease. Copyright © 2015 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Risks and benefits of the intercostal approach for percutaneous nephrolithotripsy.

PubMed

Lang, Erich K; Thomas, Raju; Davis, Rodney; Colon, Ivan; Cheung, Wellman; Sethi, Erum; Rudman, Ernest; Hanano, Amer; Myers, Leann; Kagen, Alexander

2009-01-01

The objective of our retrospective study was to provide evidence on the efficacy of the intercostal versus subcostal access route for percutaneous nephrolithotripsy. 642 patients underwent nephrolithotomy or nephrolithotripsy from 1996 to 2005. A total of 127 had an intercostal access tract (11th or 12th); 515 had a subcostal access tract. Major complications included one pneumothorax (1.0%), one arterio-calyceal fistula (1.0%) and three arteriovenous fistulae (2.7%) for intercostal upper pole access; two pneumothoraces (1.7%), one arteriovenous fistula (1.0%), one pseudoaneurysm (1.0%), one ruptured uretero-pelvic junction (1.0%), 4 perforated ureters (3.4%) for subcostal upper pole access; one hemothorax (1.6%), one colo-calyceal fistula (1.6%), one AV fistula (1.6%), and two perforated ureters (3.2%) with subcostal interpolar access. Diffuse bleeding from the tract with a subcostal interpolar approach occurred 3.2% of the time compared with 2.4% with a lower pole approach. Staghorn calculi demonstrated similar rates of complications. Considering the advantages that the intercostal access route offers the surgeon, it is reasonable to recommend its use after proper pre-procedural assessment of the anatomy, and particularly the respiratory lung motion.

Genitourinary Tuberculosis: A Rare Cause of Obstructive Uropathy in Pregnancy

PubMed Central

Duryea, Elaine L.; Sheffield, Jeanne S.

2014-01-01

Background. A rare but morbid form of extrapulmonary tuberculosis (TB), genitourinary TB is an important cause of obstructive uropathy and is likely underdiagnosed in pregnancy. Case. A 30-year-old primigravida undergoing treatment for active pulmonary TB presented with anuria at 13-14-weeks gestation. Bilateral ureteral strictures above the level of the ureterovesicular junctions were seen on imaging studies. Given her pulmonary disease, her obstructive uropathy was attributed to genitourinary TB. Bilateral percutaneous nephrostomy tubes were placed during pregnancy with successful ureteral reimplantation postpartum. Conclusion. Genitourinary TB should be considered as an etiology of urinary tract pathology during pregnancy, especially in foreign-born and immunocompromised persons. Early recognition resulting in prompt treatment can prevent further deterioration of maternal renal function and optimize pregnancy outcomes. PMID:25045558

Distribution of ureteral stones and factors affecting their location and expulsion in patients with renal colic.

PubMed

Moon, Young Joon; Kim, Hong-Wook; Kim, Jin Bum; Kim, Hyung Joon; Chang, Young-Seop

2015-10-01

To evaluate the distribution of ureteral stones and to determine their characteristics and expulsion rate based on their location. We retrospectively reviewed computed tomography (CT) findings of 246 patients who visited our Emergency Department (ED) for renal colic caused by unilateral ureteral stones between January 2013 and April 2014. Histograms were constructed to plot the distribution of stones based on initial CT findings. Data from 144 of the 246 patients who underwent medical expulsive therapy (MET) for 2 weeks were analyzed to evaluate the factors responsible for the stone distribution and expulsion. The upper ureter and ureterovesical junction (UVJ) were 2 peak locations at which stones initially lodged. Stones lodged at the upper ureter and ureteropelvic junction (group A) had a larger longitudinal diameter (4.21 mm vs. 3.56 mm, p=0.004) compared to those lodged at the lower ureter and UVJ (group B). The expulsion rate was 75.6% and 94.9% in groups A and B, respectively. There was no significant difference in the time interval from initiation of renal colic to arrival at the ED between groups A and B (p=0.422). Stone diameter was a significant predictor of MET failure (odds ratio [OR], 1.795; p=0.005) but the initial stone location was not (OR, 0.299; p=0.082). The upper ureter and UVJ are 2 peak sites at which stones lodge. For stone size 10 mm or less, initial stone lodge site is not a significant predictor of MET failure in patients who have no previous history of active stone treatment in the ureter.

When transcription goes on Holliday: Double Holliday junctions block RNA polymerase II transcription in vitro.

PubMed

Pipathsouk, Anne; Belotserkovskii, Boris P; Hanawalt, Philip C

2017-02-01

Non-canonical DNA structures can obstruct transcription. This transcription blockage could have various biological consequences, including genomic instability and gratuitous transcription-coupled repair. Among potential structures causing transcription blockage are Holliday junctions (HJs), which can be generated as intermediates in homologous recombination or during processing of stalled replication forks. Of particular interest is the double Holliday junction (DHJ), which contains two HJs. Topological considerations impose the constraint that the total number of helical turns in the DNA duplexes between the junctions cannot be altered as long as the flanking DNA duplexes are intact. Thus, the DHJ structure should strongly resist transient unwinding during transcription; consequently, it is predicted to cause significantly stronger blockage than single HJ structures. The patterns of transcription blockage obtained for RNA polymerase II transcription in HeLa cell nuclear extracts were in accordance with this prediction. However, we did not detect transcription blockage with purified T7 phage RNA polymerase; we discuss a possible explanation for this difference. In general, our findings implicate naturally occurring Holliday junctions in transcription arrest. Copyright © 2016 Elsevier B.V. All rights reserved.

Use of 3-dimensional printing technology and silicone modeling in surgical simulation: development and face validation in pediatric laparoscopic pyeloplasty.

PubMed

Cheung, Carling L; Looi, Thomas; Lendvay, Thomas S; Drake, James M; Farhat, Walid A

2014-01-01

Pediatric laparoscopy poses unique training challenges owing to smaller workspaces, finer sutures used, and potentially more delicate tissues that require increased surgical dexterity when compared with adult analogs. We describe the development and face validation of a pediatric pyeloplasty simulator using a low-cost laparoscopic dry-laboratory model developed with 3-dimensional (3D) printing and silicone modeling. The organs (the kidney, renal pelvis, and ureter) were created in a 3-step process where molds were created with 3D modeling software, printed with a Spectrum Z510 3D printer, and cast with Dragon Skin 30 silicone rubber. The model was secured in a laparoscopy box trainer. A pilot study was conducted at a Canadian Urological Association meeting. A total of 24 pediatric urology fellows and 3 experienced faculty members then assessed our skills module during a minimally invasive surgery training course. Participants had 60 minutes to perform a right-side pyeloplasty using laparoscopic tools and 5-0 VICRYL suture. Face validity was demonstrated on a 5-point Likert scale. The dry-laboratory model consists of a kidney, a replaceable dilated renal pelvis and ureter with an obstructed ureteropelvic junction, and an overlying peritoneum with an inscribed fundamentals of laparoscopic surgery pattern-cutting exercise. During initial validation at the Canadian Urological Association, participants rated (out of 5) 4.75 ± 0.29 for overall impression, 4.50 ± 0.41 for realism, and 4.38 ± 0.48 for handling. During the minimally invasive surgery course, 22 of 24 fellows and all the faculty members completed the scoring. Usability was rated 4 or 5 by 14 participants (overall, 3.6 ± 1.22 by novices and 3.7 ± 0.58 by experts), indicating that they would use the model in their own training and teaching. Esthetically, the model was rated 3.5 ± 0.74 (novices) and 3.3 ± 0.58 (experts). We developed a pediatric pyeloplasty simulator by applying a low-cost reusable model for laparoscopic training and skills acquisition. The model's usability, realism, and feel are good, it can be imaged under common modalities, and it shows promise as an educational tool. Copyright © 2014 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

Radio frequency ablation of small renal tumors:: intermediate results.

PubMed

Hwang, J J; Walther, M M; Pautler, S E; Coleman, J A; Hvizda, J; Peterson, James; Linehan, W M; Wood, B J

2004-05-01

With evolving radio frequency technology, the clinical application of radio frequency ablation (RFA) has been actively investigated in the treatment for small renal tumors. We present our intermediate patient outcomes after RFA. Since January 2001, 17 patients with a total of 24 hereditary renal tumors ranging from 1.2 to 2.85 cm were treated with RFA using the 200 W Cool-tip RF System (Radionics, Burlington, Massachusetts) under laparoscopic (9) or percutaneous (8) guidance and had a minimum 1-year followup. A percutaneous approach was considered unsuitable if kidney tumors were contiguous to bowel, ureter or large vessels. Treatment eligibility criteria included an average tumor diameter of less than 3.0 cm, tumor growth during 1 year and solid appearance with contrast enhancement (HU change greater than 20) on computerized tomography (CT). Postoperative followup consisted of CT with and without intravenous contrast, and renal function assessment at regular intervals. Median patient age was 38 years (range 20 to 51). At a median followup of 385 days (range 342 to 691), median tumor or thermal lesion diameter decreased from 2.26 to 1.62 cm (p = 0.0013), and only 1 lesion (4%), which was located centrally near the hilum, exhibited contrast enhancement (HU change greater than 10) on CT at 12 months. Of the 15 renal tumors ablated laparoscopically, 13 were in direct contact with the bowel and 2 were abutting the ureter, necessitating mobilization before RFA. Laparoscopic ultrasound was used to guide radio frequency electrode placement and monitor the ablation process in these cases. Operative time and intraoperative blood loss (mean +/- standard mean of error) were 243 +/- 29 minutes and 67 +/- 9 cc, respectively. In 1 patient whose ureter was adherent to the tumor a ureteropelvic junction obstruction developed after laparoscopic RFA, requiring open repair. At the minimum 1-year followup 23 of 24 ablated tumors lacked contrast uptake on CT, meeting our radiographic criteria of successful RFA treatment. RFA treatment of small renal tumors using the Radionics system appears to result in superior treatment outcomes compared to those of earlier series with lower radio frequency power generators. A high wattage generator might attain more consistent energy deposition with subsequent cell death in the targeted tissue due to less convective heat loss.

Effects of Lactobacillus plantarum on gut barrier function in experimental obstructive jaundice

PubMed Central

Zhou, Yu-Kun; Qin, Huan-Long; Zhang, Ming; Shen, Tong-Yi; Chen, Hong-Qi; Ma, Yan-Lei; Chu, Zhao-Xin; Zhang, Peng; Liu, Zhi-Hua

2012-01-01

AIM: To investigate the mechanisms of Lactobacillus plantarum (L. plantarum) action on gut barrier in preoperative and postoperative experimental obstructive jaundice in rats. METHODS: Forty rats were randomly divided into groups of sham-operation, bile duct ligation (BDL), BDL + L. plantarum, BDL + internal biliary drainage (IBD), and BDL + IBD + L. plantarum. Ten days after L. plantarum administration, blood and ileal samples were collected from the rats for morphological examination, and intestinal barrier function, liver function, intestinal oxidative stress and protein kinase C (PKC) activity measurement. The distribution and expression of the PKC and tight junction (TJ) proteins, such as occludin, zonula occludens-1, claudin-1, claudin-4, junction adhesion molecule-A and F-actin, were examined by confocal laser scanning microscopy, immunohistochemistry, Western blotting, real-time fluorescent quantitative polymerase chain reaction assay. RESULTS: L. plantarum administration substantially restored gut barrier, decreased enterocyte apoptosis, improved intestinal oxidative stress, promoted the activity and expression of protein kinase (BDL vs BDL + L. plantarum, 0.295 ± 0.007 vs 0.349 ± 0.003, P < 0.05; BDL + IBD vs BDL + IBD + L. plantarum, 0.407 ± 0.046 vs 0.465 ± 0.135, P < 0.05), and particularly enhanced the expression and phosphorylation of TJ proteins in the experimental obstructive jaundice (BDL vs BDL + L. plantarum, 0.266 ± 0.118 vs 0.326 ± 0.009, P < 0.05). The protective effect of L. plantarum was more prominent after internal biliary drainage ( BDL + IBD vs BDL + IBD + L. plantarum, 0.415 ± 0.105 vs 0.494 ± 0.145, P < 0.05). CONCLUSION: L. plantarum can decrease intestinal epithelial cell apoptosis, reduce oxidative stress, and prevent TJ disruption in biliary obstruction by activating the PKC pathway. PMID:22912548

Effects of Lactobacillus plantarum on gut barrier function in experimental obstructive jaundice.

PubMed

Zhou, Yu-Kun; Qin, Huan-Long; Zhang, Ming; Shen, Tong-Yi; Chen, Hong-Qi; Ma, Yan-Lei; Chu, Zhao-Xin; Zhang, Peng; Liu, Zhi-Hua

2012-08-14

To investigate the mechanisms of Lactobacillus plantarum (L. plantarum) action on gut barrier in preoperative and postoperative experimental obstructive jaundice in rats. Forty rats were randomly divided into groups of sham-operation, bile duct ligation (BDL), BDL + L. plantarum, BDL + internal biliary drainage (IBD), and BDL + IBD + L. plantarum. Ten days after L. plantarum administration, blood and ileal samples were collected from the rats for morphological examination, and intestinal barrier function, liver function, intestinal oxidative stress and protein kinase C (PKC) activity measurement. The distribution and expression of the PKC and tight junction (TJ) proteins, such as occludin, zonula occludens-1, claudin-1, claudin-4, junction adhesion molecule-A and F-actin, were examined by confocal laser scanning microscopy, immunohistochemistry, Western blotting, real-time fluorescent quantitative polymerase chain reaction assay. L. plantarum administration substantially restored gut barrier, decreased enterocyte apoptosis, improved intestinal oxidative stress, promoted the activity and expression of protein kinase (BDL vs BDL + L. plantarum, 0.295 ± 0.007 vs 0.349 ± 0.003, P < 0.05; BDL + IBD vs BDL + IBD + L. plantarum, 0.407 ± 0.046 vs 0.465 ± 0.135, P < 0.05), and particularly enhanced the expression and phosphorylation of TJ proteins in the experimental obstructive jaundice (BDL vs BDL + L. plantarum, 0.266 ± 0.118 vs 0.326 ± 0.009, P < 0.05). The protective effect of L. plantarum was more prominent after internal biliary drainage ( BDL + IBD vs BDL + IBD + L. plantarum, 0.415 ± 0.105 vs 0.494 ± 0.145, P < 0.05). L. plantarum can decrease intestinal epithelial cell apoptosis, reduce oxidative stress, and prevent TJ disruption in biliary obstruction by activating the PKC pathway.

Airway Epithelial Barrier Dysfunction in Chronic Obstructive Pulmonary Disease: Role of Cigarette Smoke Exposure.

PubMed

Aghapour, Mahyar; Raee, Pourya; Moghaddam, Seyed Javad; Hiemstra, Pieter S; Heijink, Irene H

2018-02-01

The epithelial lining of the airway forms the first barrier against environmental insults, such as inhaled cigarette smoke, which is the primary risk factor for the development of chronic obstructive pulmonary disease (COPD). The barrier is formed by airway epithelial junctions, which are interconnected structures that restrict permeability to inhaled pathogens and environmental stressors. Destruction of the epithelial barrier not only exposes subepithelial layers to hazardous agents in the inspired air, but also alters the normal function of epithelial cells, which may eventually contribute to the development of COPD. Of note, disruption of epithelial junctions may lead to modulation of signaling pathways involved in differentiation, repair, and proinflammatory responses. Epithelial barrier dysfunction may be particularly relevant in COPD, where repeated injury by cigarette smoke exposure, pathogens, inflammatory mediators, and impaired epithelial regeneration may compromise the barrier function. In the current review, we discuss recent advances in understanding the mechanisms of barrier dysfunction in COPD, as well as the molecular mechanisms that underlie the impaired repair response of the injured epithelium in COPD and its inability to redifferentiate into a functionally intact epithelium.

The Chicago classification of motility disorders: an update.

PubMed

Roman, Sabine; Gyawali, C Prakash; Xiao, Yinglian; Pandolfino, John E; Kahrilas, Peter J

2014-10-01

The Chicago Classification defines esophageal motility disorders in high resolution manometry. This is based on individual scoring of 10 swallows performed in supine position. Disorders of esophago-gastric junction (EGJ) outflow obstruction are defined by a median integrated relaxation pressure above the limit of normal and divided into 3 achalasia subtypes and EGJ outflow obstruction. Major motility disorders (aperistalsis, distal esophageal spasm, and hypercontractile esophagus) are patterns not encountered in controls in the context of normal EGJ relaxation. Finally with the latest version of the Chicago Classification, only two minor motor disorders are considered: ineffective esophageal motility and fragmented peristalsis. Copyright © 2014 Elsevier Inc. All rights reserved.

Gut metastasis from breast carcinoma.

PubMed

Al-Qahtani, Mohammed S

2007-10-01

Breast cancer is the second most common malignancy in women. Common sites of metastases include the liver, lung, bone, and the brain. Metastases to the gastrointestinal tract are rare with patients presenting with small-bowel perforation, intestinal obstruction, and gastrointestinal bleeding. Here we report a case of a Saudi female presenting with invasive lobular carcinoma and ileo-cecal junction metastasis.

[TITANIUM NICKELIDE TECHNOLOGIES IN MINIMALLY INVASIVE SURGERY OF KIDNEY AND UPPER URINARY TRACT].

PubMed

Feofilov, L V

2015-01-01

The most common pathology of the kidney and upper urinary tract includes nephrolithiasis, ureteral strictures and renal cysts. In the treatment of patients with these diseases, the majority of surgeons prefer minimally invasive techniques, including endoscopic surgery. The complication rate of percutaneous surgery is a major factor in encouraging the search for new treatments. We have analyzed the results of 402 x-ray-endoscopic operations performed with the use of technologies based on titanium nickelide materials in patients with nephrolithiasis, ureteral strictures and kidney cysts. The high effectiveness and reliability of porous titanium nickelide cryoapplicator was noted in control of percutaneous channel bleeding and prevention. The proposed suspension nephropexy with fine titanium granules in coexisting nephrolithiasis and nephroptosis demonstrated 1.5 times greater effectiveness compared to the traditional nephropexy, reducing duration of nephrostomy and rehabilitation by almost 3 times. The proposed methods of intubation by permanent and temporary stents with shape memory after percutaneous ureteropelvic junction stricture correction are promising in the treatment of patients with this pathology of the upper urinary tract. Application of titanium nickelide implants in simple renal cyst surgery has led to a significant increase in the effectiveness of these operations, improvement in long-term results and patients' quality of life.

Postoperative vesicoureteral reflux after high-pressure balloon dilation of the ureterovesical junction in primary obstructive megaureter. Incidence, management and predisposing factors.

PubMed

García-Aparicio, Luis; Blázquez-Gómez, Eva; de Haro, Irene; Garcia-Smith, Natalie; Bejarano, Miguel; Martin, Oriol; Rodo, Joan

2015-12-01

To describe the incidence, predisposing factors and management of postoperative vesicoureteral reflux (VUR) after high-pressure balloon dilation to treat primary obstructive megaureter (POM). We have reviewed patients that underwent endoscopic treatment for POM from May 2008 to November 2013. All patients were evaluated with renal ultrasound, voiding cystourethrography and diuretic renogram. Endoscopic treatment was done with high-pressure balloon dilation of the ureterovesical junction under general anesthesia; a double-J stenting was done in all patients. Follow-up was performed with ultrasonography, voiding cystourethrography and a diuretic renogram in all patients. Fifteen boys and five girls with a mean age of 14.18 months (3-103) were reviewed. A total of 22 ureters underwent HPBD to treat POM. Ureterohydronephrosis improves in 19 ureters. After endoscopic treatment, six ureters developed VUR. Four ureters were managed surgically, and in the other two, VUR disappeared in a second cystogram. The presence of parameatal diverticulum in the preoperative cystography and those patients with bilateral POM are factors related to postoperative VUR (p < 0.05). Urinary tract infection after HPBD was observed in four patients, but only one of them was affected with VUR.

Hepatic immunohistochemical localization of the tight junction protein ZO-1 in rat models of cholestasis.

PubMed Central

Anderson, J. M.; Glade, J. L.; Stevenson, B. R.; Boyer, J. L.; Mooseker, M. S.

1989-01-01

Structural alterations in hepatocyte tight junctions accompanying cholestasis were investigated using immunolocalization of ZO-1, the first known protein component of the tight junction. Disruption in the paracellular barrier function of the tight junction has been proposed to allow reflux of bile into the blood. Cholestasis was induced in 210 to 235 g male Sprague-Dawley rats either by five consecutive daily subcutaneous injections of 17-alpha-ethinyl estradiol (0.5 mg/kg/d in propylene glycol) or ligation of the common bile duct for 72 hours. The structural organization of the tight junction was assessed in each model by indirect immunofluorescent and immunoperoxidase staining for ZO-1 on frozen sections of liver and compared with controls. In control, sham-operated, and estradiol-injected animals, ZO-1 localizes in a uniform continuous manner along the margins of the canaliculi. In contrast, bile duct ligation results in the appearance of numerous discontinuities in ZO-1 staining accompanied by dilation or collapse of the lumenal space. Tissue content of the ZO-1 protein, as determined by quantitative immunoblotting, was unaffected in either cholestatic model compared with controls. These findings indicate that the molecular organization of the tight junction can be assessed from immunostaining patterns of ZO-1 in frozen sections of cholestatic livers. Under these experimental conditions, the organization of the tight junction at the level of the ZO-1 protein is altered by bile duct obstruction but not by ethinyl estradiol. Images Figure 1 Figure 2 PMID:2719075

Ureteral obstruction promotes proliferation and differentiation of the renal urothelium into a bladder-like phenotype.

PubMed

Girshovich, Alexey; Vinsonneau, Christophe; Perez, Joelle; Vandermeersch, Sophie; Verpont, Marie-Christine; Placier, Sandrine; Jouanneau, Chantal; Letavernier, Emmanuel; Baud, Laurent; Haymann, Jean-Philippe

2012-08-01

The renal urothelium, the monolayered epithelium that covers the papilla, is the direct target of increased pressure during obstruction, yet most studies have mainly focused on tubules, fibroblasts, and inflammatory cells. We studied this epithelium in a unilateral ureteral obstruction mouse mode land found that it was disrupted and had broken tight junctions, enlarged intercellular space, with loss of apicaluroplakins, and marginal lumen desquamation. Shortly after obstruction these urothelial cells proliferated, peaking at day 2. By day 14, the renal urothelium was transformed into a multilayered barrier with newly synthesized uroplakins including the de novo induction of uroplakin II. This proliferation was found to be fibroblast growth factor (FGF)dependent. Renal urothelial cells constitutively express the FGF receptor 2, and obstruction activated the receptor by phosphorylation. Treatment with FGF receptor 2-antisense or vitamin A (an inhibitor of the MAP kinase in the FGFR2 pathway) decreased renal urothelial cell proliferation. Among known FGF receptor 2 ligands, only FGF7 was upregulated.Infusion of FGF7 into control mice caused the formation of a multilayered structure at 7 days, resembling the urothelium 14 days following obstruction. Thus, the pressure/stretching of renal monolayered urothelial cells is a very efficient trigger for proliferation, causing the formation of a bladder-like multistratified barrier with enhanced apical uroplakin plaques. Presumably, this ensures efficient barrier protection and repair.

Impaired bolus clearance in combined high-resolution esophageal manometry and impedance measurement helps to differentiate between esophagogastric junction outflow obstruction and achalasia.

PubMed

Zizer, Eugen; Seufferlein, Thomas; Hänle, Mark Martin

2017-02-01

Introduction and aims  High-resolution esophageal manometry (HRM) has improved the diagnostic work-up of esophageal motility disorders. Simultaneous evaluation of bolus clearance delivers useful information about the function of tubular esophagus. We assessed bolus clearance in a combined HRM-impedance examination for esophagogastric junction outflow obstruction (EGJOO) in comparison to achalasia patients. The collected data were assessed in a retrospective analysis. Patients and methods  After gastroscopy excluded a mechanical esophageal or gastric obstruction, 142 consecutive patients underwent combined HRM-impedance examination. The assessment and interpretation of the manometry results were done according to the Chicago Classification of esophageal motility disorders v3.0. After classifying the motility disorder, the evaluation of bolus clearance was done according to published studies. Results  All patients with achalasia (n = 24) showed a significantly impaired bolus clearance (< 80 %). Patients with unaffected peristalsis (n = 56) or patients with EGJOO (n = 14) each showed impaired clearance in 7 %, respectively. The evidence of axial hernia was not associated with impaired clearance. Conclusion  Our results demonstrate a significant difference in impedance measurements between EGJOO and achalasia cases. This might be helpful as an additional tool to differentiate between achalasia and EGJOO patients. Furthermore, the role of the combined impedance-HRM investigation for early diagnosis of achalasia in "pre-achalasia" condition or in evaluation of potential progress of EGJOO to achalasia should be evaluated in a prospective study. © Georg Thieme Verlag KG Stuttgart · New York.

Investigation of Dysphagia After Antireflux Surgery by High-resolution Manometry: Impact of Multiple Water Swallows and a Solid Test Meal on Diagnosis, Management, and Clinical Outcome.

PubMed

Wang, Yu Tien; Tai, Ling Fung; Yazaki, Etsuro; Jafari, Jafar; Sweis, Rami; Tucker, Emily; Knowles, Kevin; Wright, Jeff; Ahmad, Saqib; Kasi, Madhavi; Hamlett, Katharine; Fox, Mark R; Sifrim, Daniel

2015-09-01

Management of patients with dysphagia, regurgitation, and related symptoms after antireflux surgery is challenging. This prospective, case-control study tested the hypothesis that compared with standard high-resolution manometry (HRM) with single water swallows (SWS), adding multiple water swallows (MWS) and a solid test meal increases diagnostic yield and clinical impact of physiological investigations. Fifty-seven symptomatic and 12 asymptomatic patients underwent HRM with SWS, MWS, and a solid test meal. Dysphagia and reflux were assessed by validated questionnaires. Diagnostic yield of standard and full HRM studies with 24-hour pH-impedance monitoring was compared. Pneumatic dilatation was performed for outlet obstruction on HRM studies. Clinical outcome was assessed by questionnaires and an analogue scale with "satisfactory" defined as at least 40% symptom improvement requiring no further treatment. Postoperative esophagogastric junction pressure was similar in all groups. Abnormal esophagogastric junction morphology (double high pressure band) was more common in symptomatic than in control patients (13 of 57 vs 0 of 12, P = .004). Diagnostic yield of HRM was 11 (19%), 11 (19%), and 33 of 57 (58%), with SWS, MWS, and solids, respectively (P < .001); it was greatest for solids in patients with dysphagia (19 of 27, 70%). Outlet obstruction was present in 4 (7%), 11 (19%), and 15 of 57 patients (26%) with SWS, MWS, and solids, respectively (P < .009). No asymptomatic control had clinically relevant dysfunction on solid swallows. Dilatation was performed in 12 of 15 patients with outlet obstruction during the test meal. Symptom response was satisfactory, good, or excellent in 7 of 12 (58%) with no serious complications. The addition of MWS and a solid test meal increases the diagnostic yield of HRM studies in patients with symptoms after fundoplication and identifies additional patients with outlet obstruction who benefit from endoscopic dilatation. Copyright © 2015 AGA Institute. Published by Elsevier Inc. All rights reserved.

Sleep disordered breathing in children with achondroplasia.

PubMed

Zaffanello, Marco; Cantalupo, Gaetano; Piacentini, Giorgio; Gasperi, Emma; Nosetti, Luana; Cavarzere, Paolo; Ramaroli, Diego Alberto; Mittal, Aliza; Antoniazzi, Franco

2017-02-01

Children with achondroplasia often have breathing problems, especially during sleep. The most important treatments are adenotonsillectomy (for treating upper obstruction) and/or neurosurgery (for resolving cervicomedullar junction stenosis). We reviewed the scientific literature on polysomnographic investigations which assessed the severity of respiratory disorders during sleep. Recent findings have highlighted the importance of clinical investigations in patients with achondroplasia, differentiating between those that look for neurological patterns and those that look for respiratory problems during sleep. In particular, magnetic resonance imaging (MRI) and somatosensory evoked potentials are the main tools to evaluate necessary neurosurgery and over myelopathy, respectively. The use of polysomnography enables clinicians to identify children with upper airway obstruction and to quantify disease severity; it is not suitable for MRI and/or neurosurgery considerations.

Obstructive hydrocephalus secondary to odontoid pannus: case report and review of literature.

PubMed

Soon, Wai Cheong; Thanabalasundaram, Gopiga; Thant, Kyaw Zayar; Ogbonnaya, Ebere Sunny; Harrisson, Stuart Edward

2018-04-01

Odontoid pannus or periodontoid pseudotumour is associated with a variety of rheumatological conditions. We report a case of an 80-year old man who presented with acute hydrocephalus following an emergency operation to amputate his infected left big toe. Imaging revealed a large tissue mass causing severe compression at the cervico-medullary junction and obstruction of CSF flow. The acute hydrocephalus was presumed to be related to neck manoeuvring during general anaesthesia. Following an initial emergency CSF diversion through external ventricular drainage catheter insertion, the patient subsequently underwent ventriculo-peritoneal insertion and posterior spinal decompression and fixation. To our knowledge, there have been no reported cases of tophaceous gout of the odontoid pannus causing acute hydrocephalus.

The Fate of Nephrons in Congenital Obstructive Nephropathy: Adult Recovery is Limited by Nephron Number Despite Early Release of Obstruction

PubMed Central

Sergio, Maria; Galarreta, Carolina I.; Thornhill, Barbara A.; Forbes, Michael S.; Chevalier, Robert L.

2015-01-01

Purpose Urinary tract obstruction and reduced nephron number often occur together as a result of maldevelopment of kidneys and urinary tract. We wished to determine the role of nephron number on the adaptation of remaining nephrons of mice subjected to neonatal partial unilateral ureteral obstruction (UUO) and followed through adulthood. Materials and Methods Wild-type (WT) and Os/+ mice (with 50% fewer nephrons) were subjected to sham operation or partial UUO in the first 2 days of life. Additional mice underwent release of UUO at 7 days. All kidneys were harvested at 3 weeks (weaning) or 6 weeks (adulthood). Glomerular number and area, glomerulotubular junction integrity, proximal tubular volume fraction, and interstitial fibrosis were measured by histomorphometry. Results In the obstructed kidney, UUO caused additional nephron loss in Os/+ but not WT mice. Glomerular growth from 3 to 6 weeks was impaired by ipsilateral UUO and was not preserved by release in WT or Os/+. Proximal tubular growth was impaired and interstitial collagen was increased by ipsilateral UUO in all mice. These were attenuated by release of UUO in WT mice, but were not restored in Os/+ mice. UUO increased interstitial collagen in the contralateral kidney; release of UUO enhanced tubular growth and reduced interstitial collagen. Conclusions We conclude that UUO in early postnatal development impairs adaptation to reduced nephron number and induces additional nephron loss despite release of obstruction. Premature and low birth weight infants with congenital obstructive nephropathy are likely at increased risk for progression of chronic kidney disease. PMID:25912494

Can ureteral stones cause pain without causing hydronephrosis?

PubMed

Song, Yan; Hernandez, Natalia; Gee, Michael S; Noble, Vicki E; Eisner, Brian H

2016-09-01

While computerized tomography (CT) is the gold standard for diagnosis of ureterolithiasis, ultrasound is a less costly and radiation-free alternative which is commonly used to evaluate patients with ureteral colic. The purpose of this study was to evaluate the frequency with which patients with ureteral stones and renal colic demonstrate hydronephrosis in order to better understand the evaluation of these patients. Two hundred and forty-eight consecutive patients presenting with ureteral colic and diagnosed with a single unilateral ureteral stone on CT scan in an urban tertiary care emergency department were retrospectively reviewed. Radiology reports were reviewed for stone size, diagnosis, and degree of hydronephrosis. Of the 248 patients evaluated for suspected ureteral stone, 221 (89.1 %) demonstrated any hydronephrosis, while 27 (10.9 %) did not. Hydronephrosis grade, available in 194 patients, was as follows: mild-70.6 %, moderate-27.8 %, and severe-1.5 %. Mean patient age was 47.0 years (SD 15.5), gender distribution was 35.9 % female and 64.1 % male, and mean stone axial diameter was 4.1 mm (SD 2.4). Stone location was as follows: ureteropelvic junction-4.1 %, proximal ureter-21 %, distal ureter-24.9 %, and ureterovesical junction-47.1 %. Axial stone diameter and coronal length (craniocaudal) were both significant predictors of degree of hydronephrosis (ANOVA, p < 0.001 for both). Age (ANOVA, p = NS), stone location (Chi square, p = NS), and gender (Chi square, p = NS) were not associated with degree of hydronephrosis. In patients with ureteral stones and colic, nearly 11 % do not demonstrate any hydronephrosis and a majority (nearly 71 %) will demonstrate only mild hydronephrosis. Stone diameter appears to be related to degree of hydronephrosis, whereas age, gender, and stone location are not. The lower incidence of hydronephrosis for small stones causing renal colic may explain the lower diagnostic accuracy of ultrasound when compared to CT for detecting ureteral stones.

The Impact of Preoperative α-Adrenergic Antagonists on Ureteral Access Sheath Insertion Force and the Upper Limit of Force Required to Avoid Ureteral Mucosal Injury: A Randomized Controlled Study.

PubMed

Koo, Kyo Chul; Yoon, Jun-Ho; Park, No-Cheol; Lee, Hye Sun; Ahn, Hyun Kyu; Lee, Kwang Suk; Kim, Do Kyung; Cho, Kang Su; Chung, Byung Ha; Hong, Chang Hee

2018-06-01

Excessive bulking force during primary access of the ureteral access sheath may induce ureteral injury. We investigated the efficacy of preoperative α-blockade to reduce ureteral access sheath insertion force and determine the upper limit required to avoid ureteral injury. In this randomized controlled trial 135 patients from a single institution who had ureteropelvic junction or renal pelvis stones and were scheduled to undergo retrograde intrarenal surgery were prospectively enrolled from December 2015 to January 2017. Of the patients 41 and 42 were randomly assigned to the control and experimental groups, respectively. The experimental group received α-blockade preoperatively. The 21 patients who were pre-stented were assessed separately. We developed a homemade device to measure maximal ureteral access sheath insertion force. Our ureteral access sheath insertion force measurement device showed excellent reproducibility. Higher insertion velocity resulted in greater maximal sheath insertion force. Maximal insertion force in the α-blockade group was significantly lower than in the control group at the ureterovesical junction (p = 0.008) and the proximal ureter (p = 0.036). Maximal insertion force in the α-blockade group was comparable to that in pre-stented patients. Female patients and patients 70 years old or older showed a lower maximal ureteral access sheath insertion force than their counterparts. The rate of grade 2 or greater ureteral injury was lower in the α-blockade group than in controls (p = 0.038). No injury occurred in any case in which ureteral access sheath insertion force did not exceed 600 G. Preoperative α-blockade and slow sheath placement may reduce maximal ureteral access sheath insertion force. If the force exceeds 600 G, a smaller diameter sheath may be an alternative. Alternatively the procedure can be terminated and followed later by pre-stented retrograde intrarenal surgery. Copyright © 2018 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Best Stent Length Predicted by Simple CT Measurement Rather than Patient Height.

PubMed

Barrett, Keith; Foell, Kirsten; Lantz, Andrea; Ordon, Michael; Lee, Jason Y; Pace, Kenneth T; Honey, R John D'A

2016-09-01

Ureteral stent length is important, as stents that are too long might worsen symptoms and too short are at higher risk of migration. The purpose of this study was to determine if patient or radiologic parameters correlate with directly measured ureteral length and if directly measured ureteral length predicts proper stent positioning. During stent placement, ureteral length (ureteropelvic junction to ureterovesical junction distance) was directly measured by endoscopically viewing a ureteral catheter (with 1-cm marking) emanating from the ureteral orifice. A 22, 24, or 26 cm stent was chosen to be closest to the measured ureteral length. For ureters >26 cm, a 26 cm stent was chosen. Ends of an "ideally positioned" stent were fully curled in the renal pelvis and bladder, without crossing the bladder midline. Rates of ideal stent position were compared between patients with matching stent and ureteral lengths and those with stent lengths differing by ≥1 cm (mismatched). The measured ureteral length was correlated with patient height, L1-L5 height, and length measured on CT. Fifty-nine ureters from 57 patients were included. Height was reasonably correlated with L1-L5 height (Spearman correlation coefficient [rho] = 0.79), although both were poorly correlated with directly measured ureteral length (rho = 0.18 for height and 0.32 for lumbar height). Ureteral lengths measured on CT correlated well with direct measurement (rho = 0.63 for axial cuts and rho = 0.64 for coronal cuts). Matched stent length was associated with higher rates of ideal stent position than mismatched (100% vs 70.9%, p = 0.006). CT measurements, rather than height, correlate well with measured length and could be used to choose the appropriate stent length. Stents matching directly measured ureteral lengths are associated with high rates of ideal stent position.

Primary endoscopic treatment of ureteric calculi. A review of 378 cases.

PubMed

Puppo, P; Ricciotti, G; Bozzo, W; Introini, C

1999-01-01

In the post-ESWL period, ureteroscopy represented the solution giving a second choice in the treatment of ureteral calculi in case of failure of extracorporeal lithotripsy. The aim of this study is to review a wide series of ureteral stones in which ureteroscopy combined with endoscopic lithotripsy can be chosen as the first approach for the treatment of ureteral calculi. Between January 1994 and September 1997, 378 patients underwent ureteroscopy and endoscopic lithotripsy for ureteral stones with a miniscope associated with either a pneumatic or electropneumatic lithotriptor. Three different miniscopes were used: Olympus (8 Fr), Wolf (7 Fr) and Circon Acmi (7.7 Fr). 238 patients were male and 140 were female. The stones were localized in the upper tract of the ureter in 62 cases (16.4%), 96 (25.3%) in the mid ureter and 220 (58. 3%) in the lower ureter. A complete stone fragmentation with spontaneous expulsion of the fragments occurred in 354 patients (93.6%). In 22 patients (5.8%) the stones were accidentally pushed up and successfully underwent ESWL. In 38 patients (10%) the fragments were completely removed by basket. A single J polyethylene catheter was placed in 21 (5.5%) and a JJ stent in 147 patients (38. 8%). The operative time ranged from 10 to 60 min, with an average time span of 32. In 22 cases (5.8%) an iterative ureteroscopy for stenosis or incomplete fragmentation was needed. Five cases (1.3%) of ureteral perforation were successfully treated by JJ stent, and only 1 case of ureteral avulsion (upper ureter) was treated by open surgery. In the attempt of overcoming an ureteral stenosis, we had 1 case (0.2%) of ureteral reimplantation. One patient (0.2%) underwent ureterolithotomy for an extremely narrow stenosis just before the ureteropelvic junction. No relevant complication was recorded in the postoperative period. Patients were dismissed after 1- 4 days (average 1.9). Up until now, no case of postoperative ureteral stricture has been observed, although we were not able to carry out a specific follow-up in all our patients. Ureteroscopy with miniscopes has a high success rate (93.6%) with low morbidity and can be given as a primary approach in the management of ureteral calculi. In the lumbar ureter (especially in women) this technique can represent a good alternative to ESWL in the treatment of obstructing stones (which need stenting) or when the patient asks for a 'one-shot' treatment.

Endoscopic treatment of grades IV and V vesicoureteral reflux with two bulking substances: Dextranomer hyaluronic acid copolymer versus polyacrylate polyalcohol copolymer in children.

PubMed

Kocaoglu, Canan

2016-10-01

We aimed at evaluating the efficacy and complications of two bulking substances: dextranomer/hyaluronic acid copolymer(Dx/Ha;Dexell®) versus polyacrylate polyalcohol copolymer(PPC;Vantris®) in subureteric injection treatment of children with high grades (grades IV-V) vesicoureteral reflux(VUR). Data of patients undergoing endoscopic treatment of high grade VUR (January 2009-August 2015) were retrospectively investigated. Patients with high grade VUR caused by posterior urethral valve, duplex system, paraureteral diverticula and neurogenic bladder were excluded. Classical subureteric injection method (STING) was used. Seventy-three children (45 girls and 28 boys) who had 88 refluxing renal units (RRUs) with grades IV-V VUR (n=64/n=24) underwent endoscopic treatment using Dx/Ha (n=63 RRUs) and PPC (n=25 RRUs). Mean age of patients in Dx/Ha and PPC groups were 6 (3) and 6 (3.75) year (p=0.81), and volumes of these substances given were 1.3 (1) and 1 (0.5) mL (p=0.003), respectively. Overall, for the first endoscopic injection, success rate of grades IV-V VUR per RRU was 53.9% with Dx/Ha, compared to 80% in PPC-injected group, (p=0.024). Late ureterovesical junction obstruction developed only in one patient in PPC-injected group. No ureteral obstruction was observed in Dx/Ha-injected group. Endoscopic injection of PPC resulted in significantly higher success rate, compared to Dx/Ha in subureteric injection treatment of children with high grade VUR. However, the development of late ureterovesical junction obstruction should also be taken into account in PPC injection. Copyright © 2016 Elsevier Inc. All rights reserved.

Simultaneous antegrade/retrograde upper urinary tract access: Bart's modified lateral position for complex upper tract endourologic pathologic features.

PubMed

Moraitis, Konstantinos; Philippou, Prodromos; El-Husseiny, Tamer; Wazait, Hassan; Masood, Junaid; Buchholz, Noor

2012-02-01

To determine whether the Bart's modified lateral position is safe and effective for achieving simultaneous anterograde and retrograde access in complex upper urinary tract pathologic features. From November 2006 to September 2010, 45 procedures were performed, with the patients in the modified lateral position. The indication for these procedures was the presence of complex unilateral upper urinary tract pathologic features. The patients with muscular and/or skeletal abnormalities were excluded. All procedures were performed using simultaneous anterograde and retrograde access with the patient under general anesthesia. The preoperative investigation protocol included assessment of the stone burden and location using enhanced abdominal computed tomography. The patients were routinely examined 6 weeks after the procedure with a combination of plain abdominal radiography and renal ultrasonography. For patients treated for conditions causing upper urinary tract obstruction (pelviureteral junction obstruction and/or ureteral strictures), a mercaptoacetyltriglycine renography was performed at 4, 12, and 24 months postoperatively. The mean patient age was 51.2 years (range 17-79). Stone clearance was achieved by a single combined procedure in 36 patients (80%). Successful recanalization was achieved in all patients with pelviureteral junction obstruction and ureteral strictures. In 4 patients (8.8%), persistent hematuria was noted, and 2 patients (4.4%) developed postoperative urinary sepsis and were treated conservatively. Modification to the lateral position compares equally with contemporary percutaneous nephrolithotomy series. It provides wide exposure of the flank, allowing the choice of multiple access sites, enhanced control, and a wide angle for handling of the antegrade instruments. Two surgeons can work simultaneously, addressing complex endourologic pathologic features in high-risk patients. Copyright © 2012. Published by Elsevier Inc.

Comparison of pitot traverses taken at varying distances downstream of obstructions.

PubMed

Guffey, S E; Booth, D W

1999-01-01

This study determined the deviations between pitot traverses taken under "ideal" conditions--at least seven duct diameter's lengths (i.e., distance = 7D) from obstructions, elbows, junction fittings, and other disturbances to flows--with those taken downstream from commonplace disturbances. Two perpendicular 10-point, log-linear velocity pressure traverses were taken at various distances downstream of tested upstream conditions. Upstream conditions included a plain duct opening, a junction fitting, a single 90 degrees elbow, and two elbows rotated 90 degrees from each other into two orthogonal planes. Airflows determined from those values were compared with the values measured more than 40D downstream of the same obstructions under ideal conditions. The ideal measurements were taken on three traverse diameters in the same plane separated by 120 degrees in honed drawn-over-mandrel tubing. In all cases the pitot tubes were held in place by devices that effectively eliminated alignment errors and insertion depth errors. Duct velocities ranged from 1500 to 4500 ft/min. Results were surprisingly good if one employed two perpendicular traverses. When the averages of two perpendicular traverses was taken, deviations from ideal value were 6% or less even for traverses taken as close as 2D distance from the upstream disturbances. At 3D distance, deviations seldom exceeded 5%. With single diameter traverses, errors seldom exceeded 5% at 6D or more downstream from the disturbance. Interestingly, percentage deviations were about the same at high and low velocities. This study demonstrated that two perpendicular pitot traverses can be taken as close as 3D from these disturbances with acceptable (< or = 5%) deviations from measurements taken under ideal conditions.

Multicystic dysplastic kidneys suggesting hydronephrosis during Tc-DTPA imaging

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

Siddiqui, A.R.; Cohen, M.; Mitchell, M.E.

1982-10-01

Tc-99m DTPA renal scans on two infants with flank masses were interpreted as consistent with hydronephrosis and obstruction of the uretopelvic junction because of delayed accumulation of the radiotracer in the initially photon-deficient regions. However, both these patients were found to have multicystic dysplastic kidney. It appears that for proper diagnosis more attention should be paid to the location of the functioning cortex rather than to the delayed images.

Elevated intrabolus pressure identifies obstructive processes when integrated relaxation pressure is normal on esophageal high-resolution manometry.

PubMed

Quader, Farhan; Reddy, Chanakyaram; Patel, Amit; Gyawali, C Prakash

2017-07-01

Elevated integrated relaxation pressure (IRP) on esophageal high-resolution manometry (HRM) identifies obstructive processes at the esophagogastric junction (EGJ). Our aim was to determine whether intrabolus pressure (IBP) can identify structural EGJ processes when IRP is normal. In this observational cohort study, adult patients with dysphagia and undergoing HRM were evaluated for endoscopic evidence of structural EGJ processes (strictures, rings, hiatus hernia) in the setting of normal IRP. HRM metrics [IRP, distal contractile integral (DCI), distal latency (DL), IBP, and EGJ contractile integral (EGJ-CI)] were compared among 74 patients with structural EGJ findings (62.8 ± 1.6 yr, 67.6% women), 27 patients with normal EGD (52.9 ± 3.2 yr, 70.3% women), and 21 healthy controls (27.6 ± 0.6 yr, 52.4% women). Findings were validated in 85 consecutive symptomatic patients to address clinical utility. In the primary cohort, mean IBP (18.4 ± 0.9 mmHg) was higher with structural EGJ findings compared with dysphagia with normal EGD (13.5 ± 1.1 mmHg, P = 0.002) and healthy controls (10.9 ± 0.9 mmHg, P < 0.001). However, mean IRP, DCI, DL, and EGJ-CI were similar across groups ( P > 0.05 for each comparison). During multiple rapid swallows, IBP remained higher in the structural findings group compared with controls ( P = 0.02). Similar analysis of the prospective validation cohort confirmed IBP elevation in structural EGJ processes, but correlation with dysphagia could not be demonstrated. We conclude that elevated IBP predicts the presence of structural EGJ processes even when IRP is normal, but correlation with dysphagia is suboptimal. NEW & NOTEWORTHY Integrated relaxation pressure (IRP) above the upper limit of normal defines esophageal outflow obstruction using high-resolution manometry. In patients with normal IRP, elevated intrabolus pressure (IBP) can be a surrogate marker for a structural restrictive or obstructive process at the esophagogastric junction (EGJ). This has the potential to augment the clinical value of esophageal HRM by raising suspicion for a structural EGJ process when IBP is elevated.

Epidural varix at the cervicothoracic junction: unusual cause of quadriplegia: a case report.

PubMed

Bapat, Mihir; Metkar, Umesh

2006-02-01

A case report describing an unusual incident of quadriplegia in a young adult male caused by an epidural varix at the cervicothoracic junction. To report an unusual case of quadriplegia caused by an epidural varix at the cervicothoracic junction. Epidural varices are dilated tortuous elongated veins inside the central canal. In degenerative spinal stenosis, these varices are a result of venous stagnation and contribute to the pathogenesis of radicular pain. In the absence of stenosis, primary varicosities develop as a result of dynamic obstruction to venous outflow during spinal movements. A primary epidural varix can produce neurologic deficit similar to a space occupying lesion within the spinal canal. The myeloradiculopathy is of a slow progressive nature. A young man presented with an acute onset flaccid quadriplegia in the absence of significant trauma. Magnetic resonance imaging revealed an extradural space occupying lesion at the cervicothoracic junction that was diagnosed as an isolated epidural varix during surgery. No neurologic recovery occurred. Postoperative magnetic resonance imaging revealed a syrinx in the cervicothoracic cord. In the absence of other precipitating factors, the cord injury was attributed to the epidural varix. A temporary impedance to the venous outflow with the increase in the venous pressure has been hypothesized as the mechanism of cord injury.

Acute massive gastric dilatation causing ischaemic necrosis and perforation of the stomach.

PubMed

Moslim, Maitham A; Mittal, Jay; Falk, Gavin A; Ustin, Jeffrey S; Morris-Stiff, Gareth

2017-06-15

Acute massive gastric dilatation (AMGD) is a rare distinctive condition but associates with high morbidity and mortality. Though usually seen in patients with eating disorders, many aetiologies of AMGD have been described. The distension has been reported to cause gastric necrosis with or without perforation, usually within 1-2 days of an inciting event of AMGD.We report the case of a 58-year-old male who presented with gastric perforation associated with AMGD 11 days after surgical relief of a proximal small bowel obstruction. The AMGD arose from a closed loop obstruction between a tumour at the gastro-oesophageal junction and a small bowel obstruction as a result of volvulus around a jejunal feeding tube.To our knowledge, this is the first case of a closed loop obstruction of this aetiology reported in the literature, and the presentation of this patient's AMGD was notable for the delayed onset of gastric necrosis. The patient underwent an exploratory laparotomy and a partial gastrectomy to excise a portion of his perforated stomach. Surgeons should be aware of the possibility of delayed ischaemic gastric perforation in cases of AMGD. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Prevalence of recurrent urinary tract infection in children with congenital anomalies of the kidney and urinary tract (CAKUT)

NASA Astrophysics Data System (ADS)

Ramayani, O. R.; Eyanoer, P. C.; Ritarwan, K.; Siregar, B.; Siregar, R. S.

2018-03-01

Prevalence of congenital abnormalities varies from 3.5% up to 43% in pediatrics.This wide interval is due to limited numbers of research. Limitation of data on recurrent urinary tract infection in CAKUT infants as well as symptoms which resemble other diseases makes it quite a challenge. A study of the prospective cohort was established to analyze the prevalence of recurrent UTI among CAKUT in children at Neonatal and Nephrology Paediatric Department of H.Adam Malik Hospital from 2016 to 2017.Urinalysis and urine culture were used to assess the presence of UTI. The result showed that the prevalence of UTI in CAKUT patients reached 64% in which 52% is the obstructive type and 12% non-obstructive type. Pelvic ureteric junction obstruction is the most common cause. Children with known urinary tract problems such as CAKUT are very prone to developing recurrent UTI. Due to a low survival rate of children with ESKD, new strategies are needed to prevent CAKUT, preserve renal function, and reduce associated cardiovascular morbidity. Meanwhile, children with CAKUT requires a multi-disciplinary and longer follow up.

Diagnosis and Treatment Strategy of Achalasia Subtypes and Esophagogastric Junction Outflow Obstruction Based on High-Resolution Manometry.

PubMed

Ihara, Eikichi; Muta, Kazumasa; Fukaura, Keita; Nakamura, Kazuhiko

2017-01-01

Based on Chicago Classification version 3.0, the disorders of esophagogastric junction outflow obstruction (EGJOO) include achalasia (types I, II and III) and EGJOO. Although no curative treatments are currently available for the treatment of the disorders of EGJOO, medical treatments, endoscopic pneumatic dilation (PD), laparoscopic Heller myotomy (LHM), and per-oral endoscopic myotomy (POEM) are usually the sought-after modes of treatment. Since the etiology and pathogenesis might vary depending on the types of EGJOO disorders, treatment strategies should be considered based on those subtypes. Based on the accumulated evidences, the treatment strategies of our institution are as follows: effects of medical treatments on achalasia are limited. Either PD or LHM/POEM can be considered a first-line in achalasia type I, according to the patient's wish. PD and POEM can be considered first-line in achalasia types II and III, respectively. Conversely, In EGJOO, medical treatments including drugs like acotiamide and/or diltiazem can be tested as a first-line, and PD and POEM will be considered second and third-line treatments, respectively. Key Messages: The classification of subtypes based on high-resolution manometry will help us consider which treatment option can be selected as a first-line treatment depending upon the subtypes of disorders of EGJOO. Acotiamide has the potential to cure patients with EGJOO. © 2016 S. Karger AG, Basel.

Advances in Management of Esophageal Motility Disorders.

PubMed

Kahrilas, Peter J; Bredenoord, Albert J; Carlson, Dustin A; Pandolfino, John E

2018-04-24

The widespread adoption of high-resolution manometry (HRM) has led to a restructuring in the classification of esophageal motility disorder classification summarized in the Chicago Classification, currently in version 3.0. It has become apparent that the cardinal feature of achalasia, impaired lower esophageal sphincter relaxation, can occur in several disease phenotypes: without peristalsis, with premature (spastic) distal esophageal contractions, with panesophageal pressurization, or even with preserved peristalsis. Furthermore, despite these advances in diagnostics, no single manometric pattern is perfectly sensitive or specific for idiopathic achalasia and complimentary assessments with provocative maneuvers during HRM or interrogating the esophagogastric junction with the functional luminal imaging probe during endoscopy can be useful in clarifying equivocal or inexplicable HRM findings. Using these tools, we have come to conceptualize esophageal motility disorders as characterized by obstructive physiology at the esophagogastric junction, smooth muscle esophagus, or both. Recognizing obstructive physiology as a primary target of therapy has become particularly relevant with the development of a minimally invasive technique for performing a calibrated myotomy of the esophageal circular muscle, the POEM procedure. Now and going forward, optimal management is to render treatment in a phenotype-specific manner: e.g. POEM calibrated to patient-specific physiology for spastic achalasia and spastic disorders of the smooth muscle esophagus, more conservative strategies (pneumatic dilation) for the disorders limited to the sphincter. Copyright © 2018 AGA Institute. Published by Elsevier Inc. All rights reserved.

Laparoscopic transgastric gastroplasty: a novel technique for a large esophagogastric fistula.

PubMed

McKenna, Daniel T; Ziegler, Kathryn; Selzer, Don

2014-08-01

Esophagogastric fistula is a rare complication related to severe inflammation at the gastroesophageal junction. Most causes are related to severe gastroesophageal reflux disease, previous surgery, or malignancy. This is the case of a 72-year-old man who had a laparoscopic Nissen fundoplication. He developed an esophageal obstruction from an intraesophageal pledget. It was removed laparoscopically, and the esophagotomy was buttressed with a Nissen fundoplication. Two months later he developed severe dysphagia, and an esophagogastric fistula was diagnosed. This was a large fistula measuring 20 mm in diameter. A novel hybrid technique was used to divide the fundoplication. Under endoscopic guidance, a 12-mm balloon-tipped trocar was inserted transgastrically. A linear-cutting surgical stapler was used to divide the fundoplication and reopen the gastroesophageal junction. The patient had no further dysphagia or gastroesophageal reflux.

Ileocecal Obstruction Due to Endometriosis – A Case Report and Literature Review

PubMed Central

BACALBASA, NICOLAE; BALESCU, IRINA; FILIPESCU, ALEXANDRU

2017-01-01

Endometriosis is a common finding in premenopausal women and a significant number of cases presenting digestive tract involvement at the time of diagnosis. However, most of these patients present pelvic nodules involving the rectosigmoidian junction, other digestive tract segments being less commonly affected. We present the case of a 37-year-old nulliparous woman who presented for diffuse abdominal pain and vomiting; she was diagnosed with complete ileocecal obstruction due to an endometriosis nodule in association with bilateral ovarian endometriosis lesions invading the rectosigmodian wall. A right colectomy with ileocolic anastomosis in association with bilateral cystectomy and rectosigmodian resection was successfully performed. The histopathological examination confirmed the endometriosic origin of the nodules invading the rectosigmodian and ileocecal wall, that was similar to the one described at the level of the ovarian cysts. PMID:28882972

Keyhole Surgery of the Kidney at Sultan Qaboos University Hospital, Oman

PubMed Central

Al-Marhoon, Mohammed S; Mathew, Josephkunju; Al-Lawati, Hawraa

2007-01-01

Objectives: Percutaneous access surgery of the kidneys was introduced in Sultan Qaboos University Hospital (SQUH) in 1998. We are presenting our early experience in the first 31 patients operated on over an eight year period using the percutaneous approach. Methods: A retrospective review of 25 patients, who underwent percutaneous nephrolithotomy (PCNL) for the treatment of large renal stones and 6 patients who underwent endopyelotomy for the treatment of pelviureteric junction (PUJ) obstruction. Results: In the PCNL group complete stone clearance was achieved in 68% (17/25) patients and the complication rate was 28% (7/25). In the endopyelotomy group the success rate of relief of obstruction of PUJ measured by renogram and relief of symptoms was 83% (5/6 patients). Conclusion: Our early results of PCNL are promising and comparable to international results. PMID:21748093

Radiofrequency Ablation of Renal Tumors with an Expandable Multitined Electrode: Results, Complications, and Pilot Evaluation of Cooled Pyeloperfusion for Collecting System Protection

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

Rouviere, Olivier; Badet, Lionel; Murat, Francois Joseph

2008-05-15

The objective of this study was to retrospectively evaluate the results of radiofrequency ablation (RFA) of renal tumors with an impedance-based system using an expandable multitined electrode. Twenty-two patients (30 tumors) were treated with RFA over a 7-year period, percutaneously (16 tumors) or intraoperatively (14 tumors). Follow-up imaging was performed at 1-3, 6, and 12 months and yearly thereafter. Twenty-seven of 30 tumors (19/22 patients) showed no residual tumor on the first imaging control. Two residual tumors were successfully ablated by a second RFA procedure. Our mean follow-up period was 35 months (range, 3-84 months). Two tumors that had beenmore » completely ablated based on imaging criteria recurred 11 and 48 months after RFA. One was treated by partial nephrectomy. The other one was not treated because the patient developed bone metastases. One patient had nephrectomy because of an RFA-induced ureteropelvic junction stricture. Nine patients (11 sessions) had a pyeloperfusion of cooled saline during RFA. None developed symptomatic complications, even though in three patients the ablation zone extended to the closest calyx (3-5 mm from the tumor). We conclude that RFA of renal tumors is promising, but serious complications to the collecting system must be taken into consideration. Prophylactic per-procedural cooling of the collecting system is feasible but needs further assessment.« less

When is prior ureteral stent placement necessary to access the upper urinary tract in prepubertal children?

PubMed

Corcoran, Anthony T; Smaldone, Marc C; Mally, Dev; Ost, Michael C; Bellinger, Mark F; Schneck, Francis X; Docimo, Steven G; Wu, Hsi-Yang

2008-10-01

We studied the possibility that age, height, weight and body mass index could be used to predict the likelihood of successful ureteroscopic access to the upper urinary tract without previous stent placement in prepubertal children. We retrospectively reviewed all ureteroscopic procedures for upper tract calculi in prepubertal children from 2003 to 2007. We compared age, height, weight and body mass index in patients who underwent successful primary flexible ureteroscopic access and in those who required initial stent placement to perform ureteroscopy. Successful primary ureteroscopic access to the upper tract was achieved in 18 of 30 patients (60%). There was no difference in mean age (9.9 vs 9.5 years, p = 0.8), height (132 vs 128 cm, p = 0.6), weight (37 vs 36 kg, p = 0.86) or body mass index (19.3 vs 20.5 kg/m(2), p = 0.55) between patients with successful vs unsuccessful upper tract access. Locations that prevented access to the upper urinary tract were evenly distributed among the ureteral orifice, iliac vessels and ureteropelvic junction. Age, height, weight and body mass index could not predict the likelihood of successful ureteroscopic access to the upper tract. Placement of a ureteral stent for passive ureteral dilation is not necessary for successful ureteroscopic access to the renal pelvis in prepubertal children. An initial attempt at ureteroscopy, with placement of a ureteral stent if upper tract access is unsuccessful, decreases the number of procedures while maintaining a low complication rate.

Congenital anomalies in infants conceived by assisted reproductive techniques.

PubMed

Mozafari Kermani, Ramin; Nedaeifard, Leila; Nateghi, Mohammad Reza; Shahzadeh Fazeli, Abolhassan; Ahmadi, Ebrahim; Osia, Mohammad Ali; Jafarzadehpour, Ebrahim; Nouri, Soudabeh

2012-04-01

Many studies show that congenital defects in infants conceived by assisted reproductive techniques (ART) are more than infants of normal conception (NC). The aim of this study is to determine the frequency of congenital anomalies in ART infants from Royan Institute and to compare congenital anomalies between two ART techniques.  In a cross-sectional descriptive study, 400 ART infants from Royan Institute who resided in Tehran were selected by non-random, consecutive sampling. Infants were examined twice (until 9 months of age) by a pediatrician. Infants' congenital anomalies were described by each body system or organ and type of ART. Data were analyzed by SPSS version 16 and Fisher's exact test. The frequency of different organ involvement in the two examinations were: 40 (10%) skin, 25 (6.2%) urogenital system, 21 (5.2%) gastrointestinal tract, 13 (3.2%) visual, and 8 (2%) cardiovascular system. Major congenital defects in infants conceived by in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) were hypospadiasis, inguinal hernia, patent ductus arteriosus plus ventricular septal defect (PDA + VSD), developmental dysplasia of the hip, lacrimal duct stenosis during the first year of life, hydronephrosis and urinary reflux over grade III, undescending testis, ureteropelvic junction stenosis, and torticoli. Two-thirds of ART infants had no defects. A total of 7% of IVF and ICSI infants had one of the major abovementioned congenital anomalies. This rate was higher than NC infants (2%-3%). There was no difference between the ICSI and IVF group.

Indications for nephrectomy in children: what has changed?

PubMed

Nouira, Faouzi; Sarrai, Nadia; Ghorbel, Soufiane; Sghair, Yacoub Ould Med; Khemakhem, Rachid; Chariag, Awatef; Jlidi, Said; Chaouachi, Beji

2010-04-01

The last decade has witnessed significant refinements in preoperative diagnostic evaluation and an improvement in surgical techniques and postoperative management for paediatric patients. There has been an improvement in our understanding of the natural history of some congenital renal anomalies which has caused some changes in management approach. To review the indications for nephrectomy in children between 1996 and 2008, at the departement of paediatric surgery, children's hospital in Tunis. There were 80 nephrectomies. A retrospective review of the patients' notes was performed. The 13-year period was divided into two halves (1996-2000 and 2001-2008) which were then compared. The total number of nephrectomies per year significantly increased over the period of the study (4, 6 and 8 nephrectomies per year for 1996-2000 and 2001-2008, respectively; P < 0.05), as did the number of nephrectomies for Multicystic dysplastic kidney (MCDK) (zero and 5 for 1996-2000 and 2001-2008, respectively) and wilms'tumour (8.3% and 29,16% for 1996 - 2000 and 2001 - 2008, respectively). Wilms' tumour, vesico-ureteric reflux (VUR) and pelvi-ureteric junction (PUJ) obstruction accounted for more than half of the nephrectomies (80% and 58% for 1996-2000 and 2001-2008, respectively). The proportion of nephrectomies performed for VUR did not change (15% and 12% for 1996-2000 and 2001-2008, respectively) but fewer nephrectomies were performed for pelvi-ureteric junction (PUJ) obstruction in the second half of the study period (44% and 4,16% for 1996-2000 and 2001-2008, respectively ; P < 0.05). The total number of nephrectomies, including partial nephrectomies, has increased significantly. The decrease in nephrectomies for PUJ obstruction could be accounted for by a more aggressive approach in the management and follow up of prenatally diagnosed hydronephrosis. Of note is that there was no significant change in the proportion of nephrectomies performed for VUR. On the contrary, the proportion of nephrectomies increased for neoplastic lesions and MCDK.

Chronic Gastric Volvulus with Laparoscopic Gastropexy after Endoscopic Reduction: A Case Report.

PubMed

Lee, Hye Yeon; Park, Jung Hyun; Kim, Sung Geun

2015-06-01

Gastric volvulus is an uncommon clinical entity. There are three types of gastric volvulus; organoaxial, mesenteroaxial and combined type. This condition can lead to a closed-loop obstruction or strangulation. Traditional surgical therapy for gastric volvulus is based on an open approach. Here we report a successful case of a patient with chronic gastric volvulus with a laparoscopic treatment. A 79-year-old woman came to the emergency department with epigastric pain accompanied by nausea for 2 weeks. Abdominal computed tomography revealed markedly distended stomach with transposition of gastroesophageal Junction and gastric antrum. Barium meal study revealed presence of the antrum was folded over 180 degrees that was located above gastroesophageal junction. We attempted an endoscopic reduction, but it was unsuccessful. The patient got laparoscopic anterior gastropexy. Based on our result, laparoscopic gastropexy can be considered as a good choice of the treatment for gastric volvulus.

Ccdc85C, a causative protein for hydrocephalus and subcortical heterotopia, is expressed in the systemic epithelia with proliferative activity in rats.

PubMed

Tanaka, Natsuki; Izawa, Takeshi; Takenaka, Shigeo; Yamate, Jyoji; Kuwamura, Mitsuru

2015-07-01

Coiled-coil domain containing 85c (Ccdc85c) is a causative gene for spontaneous mutant mouse with non-obstructive hydrocephalus and subcortical heterotopia. Detailed functions of Ccdc85C protein have not been clarified. To reveal roles of Ccdc85C, we examined the distribution and expression pattern of Ccdc85C in the systemic developing organs in rats. Ccdc85C was expressed in various simple epithelia but not stratified epithelia. In the various epithelia, Ccdc85C was localized at cell-cell junctions and its expression was strong at apical junctions. Furthermore, intense expression was seen at developing period and gradually decreased with advancing development. Distribution of Ccdc85C coincides with that of proliferating epithelial cells. These results suggest that Ccdc85C plays an important role in the proliferative property of simple epithelia.

Ileocecal Obstruction Due to Endometriosis - A Case Report and Literature Review.

PubMed

Bacalbasa, Nicolae; Balescu, Irina; Filipescu, Alexandru

2017-01-01

Endometriosis is a common finding in premenopausal women and a significant number of cases presenting digestive tract involvement at the time of diagnosis. However, most of these patients present pelvic nodules involving the rectosigmoidian junction, other digestive tract segments being less commonly affected. We present the case of a 37-year-old nulliparous woman who presented for diffuse abdominal pain and vomiting; she was diagnosed with complete ileocecal obstruction due to an endometriosis nodule in association with bilateral ovarian endometriosis lesions invading the rectosigmodian wall. A right colectomy with ileocolic anastomosis in association with bilateral cystectomy and rectosigmodian resection was successfully performed. The histopathological examination confirmed the endometriosic origin of the nodules invading the rectosigmodian and ileocecal wall, that was similar to the one described at the level of the ovarian cysts. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Case Report: A Rare Cause of Complicated Urinary Tract Infection in a Woman with Herlyn-Werner-Wunderlich Syndrome.

PubMed

Tsai, Jun-Li; Tsai, Shang-Feng

2016-11-01

Urinary tract infection is a common disease in the general population. However, in patients with frequent urinary tract infection, it is important to determine any treatable cause to avoid recurrence. Herlyn-Werner-Wunderlich syndrome or OHVIRA syndrome is a very rare congenital anomaly with uterus didelphys, obstructed hemivagina, and ipsilateral renal agenesis. The earliest presentation of this syndrome is hematocolpos that develops during menstruation and results in dysmenorrhea and a pelvic mass shortly after menarche. Herein, we report a patient with Herlyn-Werner-Wunderlich syndrome manifested with unusual symptoms, delayed onset and without surgery. The unique point of this patient is the partial obstruction of cervico-vaginal junction. Early diagnosis and timely treatment of OHVIRA syndrome can prevent long-term complications, such as recurrent urinary tract infection and infertility. A high index of suspicion is required, even though OHVIRA syndrome is extremely rare and may have an atypical presentation.

Pancreas-sparing duodenectomy for an obstructive adenocarcinoma of the duodenum

PubMed Central

Lam, D; Croome, KP; Hernandez-Alejandro, R

2012-01-01

A duodenal adenocarcinoma arising from the junction of the second and third portion of the duodenum, which was resected by pancreas-sparing duodenectomy, is reported. The completely obstructing tumour was circumferential and measured 6.5cm x 3.5cm x 1.0 cm. There was no evidence of pancreas invasion, nor any lymph node metastasis. Pancreas-sparing duodenectomy was performed, with dissection of the pancreaticoduodenal lymph nodes. The proximal duodenum was transected just distal to the ampula of Vater and jejunum was transected just distal to the ligament of Treitz. A hand-sewn side-to-side anastomosis for the duodenojejunostomy was performed. There were no postoperative complications. Pathology reported a duodenal adenocarcinoma resected with negative margins. Pancreaticoduodenectomy is the treatment of choice for a duodenal adenocarcinoma, however, pancreas-sparing duodenectomy may be a safe alternative for duodenal tumours not involving the 2nd portion, especially in elderly patients with multiple medical comorbidities. PMID:24960771

Pancreas-sparing duodenectomy for an obstructive adenocarcinoma of the duodenum.

PubMed

Lam, D; Croome, Kp; Hernandez-Alejandro, R

2012-08-01

A duodenal adenocarcinoma arising from the junction of the second and third portion of the duodenum, which was resected by pancreas-sparing duodenectomy, is reported. The completely obstructing tumour was circumferential and measured 6.5cm x 3.5cm x 1.0 cm. There was no evidence of pancreas invasion, nor any lymph node metastasis. Pancreas-sparing duodenectomy was performed, with dissection of the pancreaticoduodenal lymph nodes. The proximal duodenum was transected just distal to the ampula of Vater and jejunum was transected just distal to the ligament of Treitz. A hand-sewn side-to-side anastomosis for the duodenojejunostomy was performed. There were no postoperative complications. Pathology reported a duodenal adenocarcinoma resected with negative margins. Pancreaticoduodenectomy is the treatment of choice for a duodenal adenocarcinoma, however, pancreas-sparing duodenectomy may be a safe alternative for duodenal tumours not involving the 2(nd) portion, especially in elderly patients with multiple medical comorbidities. © JSCR.

Upper esophageal sphincter (UES) metrics on high-resolution manometry (HRM) differentiate achalasia subtypes.

PubMed

Blais, P; Patel, A; Sayuk, G S; Gyawali, C P

2017-12-01

The upper esophageal sphincter (UES) reflexively responds to bolus presence within the esophageal lumen, therefore UES metrics can vary in achalasia. Within consecutive patients undergoing esophageal high-resolution manometry (HRM), 302 patients (58.2±1.0 year, 57% F) with esophageal outflow obstruction were identified, and compared to 16 asymptomatic controls (27.7±0.7 year, 56% F). Esophageal outflow obstruction was segregated into achalasia subtypes 1, 2, and 3, and esophagogastric junction outflow obstruction (EGJOO with intact peristalsis) using Chicago Classification v3.0. UES and lower esophageal sphincter (LES) metrics were compared between esophageal outflow obstruction and normal controls using univariate and multivariate analysis. Linear regression excluded multicollinearity of pressure metrics that demonstrated significant differences across individual subtype comparisons. LES integrated relaxation pressure (IRP) had utility in differentiating achalasia from controls (P<.0001), but no utility in segregating between subtypes (P=.27). In comparison to controls, patients collectively demonstrated univariate differences in UES mean basal pressure, relaxation time to nadir, recovery time, and residual pressure (UES-RP) (P≤.049). UES-RP was highest in type 2 achalasia (P<.0001 compared to other subtypes and controls). In multivariate analysis, only UES-RP retained significance in comparison between each of the subgroups (P≤.02 for each comparison). Intrabolus pressure was highest in type 3 achalasia; this demonstrated significant differences across some but not all subtype comparisons. Nadir UES-RP can differentiate achalasia subtypes within the esophageal outflow obstruction spectrum, with highest values in type 2 achalasia. This metric likely represents a surrogate marker for esophageal pressurization. © 2017 John Wiley & Sons Ltd.

Noninvasive Assessment of Antenatal Hydronephrosis in Mice Reveals a Critical Role for Robo2 in Maintaining Anti-Reflux Mechanism

PubMed Central

Wang, Hang; Li, Qinggang; Liu, Juan; Mendelsohn, Cathy; Salant, David J.; Lu, Weining

2011-01-01

Antenatal hydronephrosis and vesicoureteral reflux (VUR) are common renal tract birth defects. We recently showed that disruption of the Robo2 gene is associated with VUR in humans and antenatal hydronephrosis in knockout mice. However, the natural history, causal relationship and developmental origins of these clinical conditions remain largely unclear. Although the hydronephrosis phenotype in Robo2 knockout mice has been attributed to the coexistence of ureteral reflux and obstruction in the same mice, this hypothesis has not been tested experimentally. Here we used noninvasive high-resolution micro-ultrasonography and pathological analysis to follow the progression of antenatal hydronephrosis in individual Robo2-deficient mice from embryo to adulthood. We found that hydronephrosis progressed continuously after birth with no spontaneous resolution. With the use of a microbubble ultrasound contrast agent and ultrasound-guided percutaneous aspiration, we demonstrated that antenatal hydronephrosis in Robo2-deficient mice is caused by high-grade VUR resulting from a dilated and incompetent ureterovesical junction rather than ureteral obstruction. We further documented Robo2 expression around the developing ureterovesical junction and identified early dilatation of ureteral orifice structures as a potential fetal origin of antenatal hydronephrosis and VUR. Our results thus demonstrate that Robo2 is crucial for the formation of a normal ureteral orifice and for the maintenance of an effective anti-reflux mechanism. This study also establishes a reproducible genetic mouse model of progressive antenatal hydronephrosis and primary high-grade VUR. PMID:21949750

Concomitant management of renal calculi and pelvi-ureteric junction obstruction with robotic laparoscopic surgery.

PubMed

Atug, Fatih; Castle, Erik P; Burgess, Scott V; Thomas, Raju

2005-12-01

To present technical recommendations for robotic-assisted laparoscopic pyeloplasty (RALP) and stone extraction, as patients with kidney stones proximal to a pelvi-ureteric junction obstruction (PUJO) present a technical challenge, and have traditionally been managed with open surgery or percutaneous antegrade endopyelotomy. From November 2002 to April 2005, 55 patients had RALP for PUJO; eight of these had concomitant renal calculi. Stone burden and location were assessed with a preoperative radiological examination. Before completing the PUJO repair, one robot working arm (cephalad one) was temporarily undocked to allow passage of a flexible nephroscope into the renal pelvis and collecting systems under direct vision. Stones were extracted with graspers or basket catheters and removed via the port. The surgical-assistant port in the subxiphoid area was used to introduce laparoscopic suction and other instruments. The Anderson-Hynes dismembered pyeloplasty was the preferred reconstructive technique in all patients. Operations were completed robotically with no conversions to open surgery. All patients were rendered stone-free, confirmed by imaging, and there were no intraoperative or delayed complications during a mean (range) follow-up of 12.3 (4-22) months. The mean operative time was 275.8 min, 61.7 min longer than in patients who did not have concomitant stone removal. Concurrent stone extraction and PUJO repair can be successful with RALP. Operative times are longer than in patients with isolated PUJO repair, but this is to be expected as there is an additional procedure.

Direct numerical simulation of transitional hydrodynamics of the cerebrospinal fluid in Chiari I malformation: The role of cranio-vertebral junction.

PubMed

Jain, Kartik; Ringstad, Geir; Eide, Per-Kristian; Mardal, Kent-André

2017-09-01

Obstruction to the cerebrospinal fluid (CSF) outflow caused by the herniation of cerebellar tonsils as a result of Chiari malformation type I leads to altered CSF hydrodynamics. This contribution explores the minutest characteristics of the CSF hydrodynamics in cervical subarachnoid space (SAS) of a healthy subject and 2 Chiari patients by performing highly resolved direct numerical simulation. The lattice Boltzmann method is used for the simulations because of its scalability on modern supercomputers that allow us to simulate up to approximately 10 9 cells while resolving the Kolmogorov microscales. The results depict that whereas the complex CSF flow remains largely laminar in the SAS of a healthy subject, constriction of the cranio-vertebral junction in Chiari I patients causes manifold fluctuations in the hydrodynamics of the CSF. These fluctuations resemble a flow that is in a transitional regime rather than laminar or fully developed turbulence. The fluctuations confine near the cranio-vertebral junction and are triggered due to the tonsillar herniation, which perturbs the flow as a result of altered anatomy of the SAS. Copyright © 2016 John Wiley & Sons, Ltd.

Primary Esophageal Motility Disorders: Beyond Achalasia.

PubMed

Schlottmann, Francisco; Patti, Marco G

2017-06-30

The best-defined primary esophageal motor disorder is achalasia. However, symptoms such as dysphagia, regurgitation and chest pain can be caused by other esophageal motility disorders. The Chicago classification introduced new manometric parameters and better defined esophageal motility disorders. Motility disorders beyond achalasia with the current classification are: esophagogastric junction outflow obstruction, major disorders of peristalsis (distal esophageal spasm, hypercontractile esophagus, absent contractility) and minor disorders of peristalsis (ineffective esophageal motility, fragmented peristalsis). The aim of this study was to review the current diagnosis and management of esophageal motility disorders other than achalasia.

Primary Esophageal Motility Disorders: Beyond Achalasia

PubMed Central

Schlottmann, Francisco; Patti, Marco G.

2017-01-01

The best-defined primary esophageal motor disorder is achalasia. However, symptoms such as dysphagia, regurgitation and chest pain can be caused by other esophageal motility disorders. The Chicago classification introduced new manometric parameters and better defined esophageal motility disorders. Motility disorders beyond achalasia with the current classification are: esophagogastric junction outflow obstruction, major disorders of peristalsis (distal esophageal spasm, hypercontractile esophagus, absent contractility) and minor disorders of peristalsis (ineffective esophageal motility, fragmented peristalsis). The aim of this study was to review the current diagnosis and management of esophageal motility disorders other than achalasia. PMID:28665309

Treatment of Post-Stent Gastroesophageal Reflux by Anti-Reflux Z-Stent

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

Davies, Roger Philip; Kew, Jacqueline; Byrne, Peter D.

2000-11-15

Severe symptoms of heartburn and retrosternal pain consistent with gastro-esophageal reflux (GER) developed in a patient following placement of a conventional self-expanding 16-24-mm-diameter x 12-cm-long esophageal stent across the gastroesophageal junction to treat an obstructing esophageal carcinoma. A second 18-mm-diameter x 10-cm-long esophageal stent with anti-reflux valve was deployed coaxially and reduced symptomatic GER immediately. Improvement was sustained at 4-month follow-up. An anti-reflux stent can be successfully used to treat significant symptomatic GER after conventional stenting.

Transanal repair of rectocele and full rectal mucosectomy with one circular stapler: a novel surgical technique.

PubMed

Regadas, F S P; Regadas, S M M; Rodrigues, L V; Misici, R; Silva, F R; Regadas Filho, F S P

2005-04-01

We present a new surgical stapling technique for treatment of rectocele when associated with internal mucosal prolapse or haemorrhoids using only one circular mechanical stapler. Eight female patients, mean age 53 years (range, 42-70), complaining of obstructed defecation with vaginal digitation because of rectocele associated with internal mucosal prolapse underwent transanal repair of rectocele and rectal mucosectomy using one circular stapler between April and July 2004. A running horizontal mattress suture was placed through the base of the rectocele including mucosa, submucosa and the muscle layer of the whole anterior anorectal junction wall. The prolapsed mucosa and the muscular layer were then excised with an electrical scapel. A continuous pursestring rectal mucosa suture was placed 0.5 cm before the previous anterior mucosa and muscle layers resected wound, including the anorectal junction wall which was kept separate from the posterior vaginal wall by a Babcock forceps. Posteriorly, the pursestring suture included only mucosal and submucosal layers. The stapled suture was positioned between normal anterior rectal wall and the anal canal, 0.5 cm above the pectinate line. The stapler was then closed, fired and withdrawn. One patient complained of a perianal hematoma on the seventh postoperative day, requiring surgical excision. Postoperative defecography showed correction of the rectocele and outlet obstruction disappeared in all patients. This novel combined manual-stapled technique for rectocele and rectal internal mucosal prolapse seems to be a safe procedure and the preliminary results are encouraging. Further investigations have to be performed to assess long-term outcome in a larger number of patients.

Three-dimensional printed prototypes refine the anatomy of post-modified Norwood-1 complex aortic arch obstruction and allow presurgical simulation of the repair.

PubMed

Kiraly, Laszlo; Tofeig, Magdi; Jha, Neerod Kumar; Talo, Haitham

2016-02-01

Three-dimensional (3D) printed prototypes of malformed hearts have been used for education, communication, presurgical planning and simulation. We present a case of a 5-month old infant with complex obstruction at the neoaortic to transverse arch and descending aortic junction following the neonatal modified Norwood-1 procedure for hypoplastic left heart syndrome. Digital 3D models were created from a routine 64-slice CT dataset; then life-size solid and magnified hollow models were printed with a 3D printer. The solid model provided further insights into details of the anatomy, whereas the surgical approach and steps of the operation were simulated on the hollow model. Intraoperative assessment confirmed the anatomical accuracy of the 3D models. The operation was performed in accordance with preoperative simulation: sliding autologous flaps achieved relief of the obstruction without additional patching. Knowledge gained from the models fundamentally contributed to successful outcome and improved patient safety. This case study presents an effective use of 3D models in exploring complex spatial relationship at the aortic arch and in simulation-based planning of the operative procedure. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

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

Micromixer utilizing electrokinetic instability-induced shedding effect.

PubMed

Tai, Chang-Hsien; Yang, Ruey-Jen; Huang, Min-Zhong; Liu, Chia-Wei; Tsai, Chien-Hsiung; Fu, Lung-Ming

2006-12-01

This paper presents a T-shaped micromixer featuring 45 degrees parallelogram barriers (PBs) within the mixing channel. The presented device obtains a rapid mixing of two sample fluids with conductivity ratio of 10:1 (sample concentration:running buffer concentration) by means of the electrokinetic instability-induced shedding effects which are produced when a direct current (DC) electric field of an appropriate intensity is applied. The presented device uses a single high-voltage power source to simultaneously drive and mix the sample fluids. The effectiveness of the mixer is characterized experimentally as a function of the applied electrical field intensity and the extent to which the PBs obstruct the mixing channel. The experimental results indicate that the mixing performance reaches 91% at a cross-section located 2.3 mm downstream of the T-junction when the barriers obstruct 4/5 of the channel width and an electrical field of 300 V/cm is applied. The micromixing method presented in this study provides a simple low-cost solution to mixing problems in lab-on-a-chip systems.

Successful treatment of a 14-year-old patient with intestinal malrotation with laparoscopic Ladd procedure: case report and literature review

PubMed Central

2013-01-01

Midgut malrotation is an anomaly of intestinal rotation that occurs during fetal development and usually presents in the neonatal period. We present a rare case of malrotation in a 14-year-old patient who presented with cramping, generalized right abdominal pain, and vomiting for a duration of one day. A computed tomography abdominal scan and upper gastrointestinal contrast studies showed malrotation of the small bowel without volvulus. Laparoscopy revealed typical Ladd’s bands and a distended flabby third and fourth duodenal portion extrinsically obstructing the misplaced duodeno-jejunal junction. The Ladd procedure, including widening of the mesenteric base and appendectomy, was performed. Symptoms completely resolved in a half-year follow up period. Patients with midgut malrotation may present with vague abdominal pain, intestinal obstruction, or intestinal ischemia. The laparoscopic Ladd procedure is feasible and safe, and it appears to be as effective as the standard open Ladd procedure in the diagnosis and treatment of teenage or adult patients with intestinal malrotation. PMID:23684081

Integrated Genomics Reveals Convergent Transcriptomic Networks Underlying Chronic Obstructive Pulmonary Disease and Idiopathic Pulmonary Fibrosis.

PubMed

Kusko, Rebecca L; Brothers, John F; Tedrow, John; Pandit, Kusum; Huleihel, Luai; Perdomo, Catalina; Liu, Gang; Juan-Guardela, Brenda; Kass, Daniel; Zhang, Sherry; Lenburg, Marc; Martinez, Fernando; Quackenbush, John; Sciurba, Frank; Limper, Andrew; Geraci, Mark; Yang, Ivana; Schwartz, David A; Beane, Jennifer; Spira, Avrum; Kaminski, Naftali

2016-10-15

Despite shared environmental exposures, idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease are usually studied in isolation, and the presence of shared molecular mechanisms is unknown. We applied an integrative genomic approach to identify convergent transcriptomic pathways in emphysema and IPF. We defined the transcriptional repertoire of chronic obstructive pulmonary disease, IPF, or normal histology lungs using RNA-seq (n = 87). Genes increased in both emphysema and IPF relative to control were enriched for the p53/hypoxia pathway, a finding confirmed in an independent cohort using both gene expression arrays and the nCounter Analysis System (n = 193). Immunohistochemistry confirmed overexpression of HIF1A, MDM2, and NFKBIB members of this pathway in tissues from patients with emphysema or IPF. Using reads aligned across splice junctions, we determined that alternative splicing of p53/hypoxia pathway-associated molecules NUMB and PDGFA occurred more frequently in IPF or emphysema compared with control and validated these findings by quantitative polymerase chain reaction and the nCounter Analysis System on an independent sample set (n = 193). Finally, by integrating parallel microRNA and mRNA-Seq data on the same samples, we identified MIR96 as a key novel regulatory hub in the p53/hypoxia gene-expression network and confirmed that modulation of MIR96 in vitro recapitulates the disease-associated gene-expression network. Our results suggest convergent transcriptional regulatory hubs in diseases as varied phenotypically as chronic obstructive pulmonary disease and IPF and suggest that these hubs may represent shared key responses of the lung to environmental stresses.

Clinicomanometric factors associated with clinically relevant esophagogastric junction outflow obstruction from the Sandhill high-resolution manometry system.

PubMed

Song, B G; Min, Y W; Lee, H; Min, B-H; Lee, J H; Rhee, P-L; Kim, J J

2018-03-01

Integrated relaxation pressure (IRP) is a key metric for diagnosing esophagogastric junction outflow obstruction (EGJOO). However, its normal value might be different according to the manufacturer of high-resolution manometry (HRM). This study aimed to investigate optimal value of IRP for diagnosing EGJOO in Sandhill HRM and to find clinicomanometric variables to segregate clinically relevant EGJOO. We analyzed 262 consecutive subjects who underwent HRM between June 2011 and December 2016 showing elevated median IRP (> 15 mm Hg) but did not satisfy criteria for achalasia. Clinically relevant subjects were defined as follows: (i) subsequent HRM met achalasia criteria during follow-up (early achalasia); (ii) Eckardt score was decreased at least two points without exceeding a score of 3 after pneumatic dilatation (variant achalasia); and (iii) significant passage disturbance on esophagogram without structural abnormality (possible achalasia). Seven subjects were clinically relevant, including two subjects with early achalasia, four subjects with variant achalasia, and one subject with possible achalasia. All clinically relevant subjects had IRP 20 mm Hg or above. Among subjects (n = 122) with IRP 20 mm Hg or more, clinically relevant group (n = 7) had significantly higher rate of dysphagia (100% vs 24.3%, P < .001) and compartmentalized pressurization (85.7% vs 21.7%, P = .001) compared to clinically non-relevant group (n = 115). Our results suggest that IRP of 20 mm Hg or higher could segregate clinically relevant subjects showing EGJOO in Sandhill HRM. Additionally, if subjects have both dysphagia and compartmentalized pressurization, careful follow-up is essential. © 2017 John Wiley & Sons Ltd.

CT-Guided Microwave Ablation of 45 Renal Tumors: Analysis of Procedure Complexity Utilizing a Percutaneous Renal Ablation Complexity Scoring System.

PubMed

Mansilla, Alberto V; Bivins, Eugene E; Contreras, Francisco; Hernandez, Manuel A; Kohler, Nathan; Pepe, Julie W

2017-02-01

To develop a scoring system that stratifies complexity of percutaneous ablation of renal tumors. Analysis was performed of 36 consecutive patients (mean age, 64 y; range, 30-89 y) who underwent CT-guided microwave (MW) ablation of 45 renal tumors (mean tumor diameter, 2.4 cm; range, 1.2-4.0 cm). Technical success and effectiveness were determined based on intraprocedural and follow-up imaging studies. The RENAL score and the proposed percutaneous renal ablation complexity (P-RAC) score were calculated for each tumor. Technical success was 93.3% (n = 42). Biopsy of 38 of 45 renal tumors revealed 23 renal cell carcinomas. Median follow-up period was 9.7 months (range, 2.9-46.8 months). There were no tumor recurrences. One major complication, ureteropelvic junction stricture, occurred (2.6%). The P-RAC score was found to differ statistically from the RENAL score (t = 3.754, df = 44, P = .001). A positive correlation was found between the P-RAC score and number of antenna insertions (r = .378, n = 45, P = .011) and procedure duration (r = .328, n = 45, P = .028). No correlation was found between the RENAL score and number of MW antenna insertions (r = .110, n = 45, P = .472) or procedure duration (r = .263, n = 45, P = .081). Hydrodissection was significantly more common in the P-RAC high-complexity category than in low-complexity category (χ 2 = 12.073, df = 2, P = .002). The P-RAC score may be useful in stratifying percutaneous renal ablation complexity. Further studies with larger sample sizes are necessary to validate the P-RAC score and to determine if it can predict risk of complications. Copyright © 2016 SIR. Published by Elsevier Inc. All rights reserved.

Mechanisms of repetitive retrograde contractions in response to sustained esophageal distension: a study evaluating patients with postfundoplication dysphagia.

PubMed

Carlson, Dustin A; Kahrilas, Peter J; Ritter, Katherine; Lin, Zhiyue; Pandolfino, John E

2018-03-01

Repetitive retrograde contractions (RRCs) in response to sustained esophageal distension are a distinct contractility pattern observed with functional luminal imaging probe (FLIP) panometry that are common in type III (spastic) achalasia. RRCs are hypothesized to be indicative of either impaired inhibitory innervation or esophageal outflow obstruction. We aimed to apply FLIP panometry to patients with postfundoplication dysphagia (a model of esophageal obstruction) to explore mechanisms behind RRCs. Adult patients with dysphagia after Nissen fundoplication ( n = 32) or type III achalasia ( n = 25) were evaluated with high-resolution manometry (HRM) and upper endoscopy with FLIP. HRM studies were assessed for outflow obstruction and spastic features: premature contractility, hypercontractility, and impaired deglutitive inhibition during multiple-rapid swallows. FLIP studies were analyzed to determine the esophagogastric junction (EGJ)-distensibility index and contractility pattern, including RRCs. Barium esophagram was evaluated when available. RRCs were present in 8/32 (25%) fundoplication and 19/25 (76%) achalasia patients ( P < 0.001). EGJ outflow obstruction was detected in 21 (67%) fundoplication patients by HRM, FLIP, or esophagram [6 (29%) had RRCs]. On HRM, none of the fundoplication patients had premature contractility, whereas 3/4 with defective inhibition on multiple-rapid swallows and 2/4 with hypercontractility had RRCs. Regression analysis demonstrated HRM with spastic features, but not esophageal outflow obstruction, as a predictor for RRCs. RRCs in response to sustained esophageal distension appear to be a manifestation of spastic esophageal motility. Although future study to further clarify the significance of RRCs is needed, RRCs on FLIP panometry should prompt evaluation for a major motor disorder. NEW & NOTEWORTHY Repetitive retrograde contractions (RRCs) are a common response to sustained esophageal distension among spastic achalasia patients when evaluated with the functional luminal imaging probe. We evaluated patients with postfundoplication dysphagia, i.e., patients with suspected mechanical obstruction, and found that RRCs occasionally occurred among postfundoplication patients, but often in association with manometric features of esophageal neuromuscular imbalance. Thus, RRCs appear to be a manifestation of spastic esophageal dysmotility, likely from neural imbalance resulting in excess excitation.

Laparoscopic trans-mesocolic pyeloplasty in children: initial experience from a center in India.

PubMed

Khan, Muneer; Ahangar, Shahnawaz; Nazir, Syed Sajjad; Qadri, Syed Javid Farooq; Salroo, Nazir Ahmad

2011-07-01

The aim of the present study is to report our experience with laparoscopic pyeloplasty via trans-mesocolic approach in children with left pelvi-ureteric junction (PUJ) obstruction. Between May 2007 and May 2008, 12 children aged between five and 16 years, with documented PUJ obstruction on the left side, underwent laparoscopic pyeloplasty via trans-mesocolic approach. The outcome was assessed by post-operative isotope renal scan. The mean age of the study patients was eight years, ranging between five and 16 years. There were five males and seven females in the study. All children underwent Anderson Hynes Pyeloplasty by a single surgeon. All cases were stented with a JJ stent for a period of six weeks post-operatively. The procedures were completed successfully in all patients without need for conversion to open pyeloplasty in any patient. The mean operative time was 95 min, with a range of 80-140 min. The average blood loss was 57 mL. The mean hospital stay was 3.5 days with a range of 2.5 to six days. All children returned back to school within nine days following surgery. The mean follow-up period was 12 months (range, nine to 14 months). Eleven of the patients were completely asymptomatic, while one reported mild flank pain. All children underwent renal scans and renal ultrasound three months after stent removal. Ten had improved function on the scan while in one patient, the function remained the same and, in another, it showed obstructed response to diuretic, although the symptoms had improved. In all the cases, renal ultrasound showed a decrease in the severity of hydronephrosis by at least one degree. These results confirm that laparoscopic pyeloplasty by trans-mesocolic approach in children for left-sided PUJ obstruction is safe and feasible.

Correlates of diuretic renography in experimental hydronephrosis

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

Kekomaeki, M.R.; Rikalainen, H.; Ruotsalainen, P.

1989-02-01

We studied the correlations between diuretic renographs and kidney function in experimental hydronephrosis in rabbits. Features of furosemide-stimulated /sup 99m/Tc-diethylenetriamine-pentaacetic acid renographs were compared to the growth rate, thirst test and endogenous creatinine clearance rate in a chronic solitary-kidney animal model. Intravenous pyelograms, done four weeks after laparotomy, left nephrectomy, bladder resection and constriction of the right pyeloureteric junction, showed signs of obstruction in all the 12 animals of the experimental group. An absent tracer washout after intravenous furosemide, found in five animals, was associated with retarded growth, isosthenuria and an abnormal creatinine clearance. In all of the other sevenmore » animals, a distinct tracer washout after intravenous furosemide was accompanied with a normal growth rate and creatinine clearance. However, no one of these seven animals had a normal ability to retain water and concentrate urine in the thirst test. We conclude that, in this experimental model, a furosemide-induced tracer washout from the kidney pelvis cannot be taken as a proof of the absence of any upper urinary tract obstruction.« less

Application of memory metallic stents to urinary tract disorders in pediatric patients.

PubMed

Kamata, Shinkichi; Usui, Noriaki; Kamiyama, Masafumi; Yoneda, Akihiro; Tazuke, Yuko; Ooue, Takaharu

2005-03-01

The use of memory metallic stents for the urinary tract in pediatric patients has not been reported. The authors report on 2 patients with urinary tract disorders who were successfully treated with a memory metallic stent. A thermoexpandable, nickel-titanium alloy stent was placed at the urethroureteral junction of a 4-year-old boy with ureteral stenosis associated with cloacal exstrophy for 18 months and at the urethra of a 2-year-old girl with ischuria after a repair of cloacal anomaly for 6 months. Temporary insertion of a memory metallic stent is a safe and effective alternative for organic stricture or functional obstruction of the urinary tract in pediatric patients.

[Tetralogy of Fallot associated with left atrial isomerism].

PubMed

Ferrín, L M; Atik, E; Aiello, V; Marcial, M B; Ebaid, M

1996-10-01

The association of tetralogy of Fallot with atrial isomerism has been rarely reported. Eight cases (five with left isomerism and three with right isomerism) are known. This paper reports two other cases of tetralogy of Fallot with left atrial isomerism. The syndrome's defects were disguised and without clinical expression because of the presence of the right ventricular outlet obstruction of tetralogy of Fallot. These diagnostic elements, not recognized in one of the patients previous to surgical correction of tetralogy of Fallot, were present: junctional rhythm, bronchial isomerism, partial anomalous pulmonary vein connection, agenesy of inferior vena cava and abdominal heterotaxy; their identification previous to surgical correction of tetralogy of Fallot, is necessary for an adequate surgical management.

980-nm diode laser and fiber optic resectoscope in endourological surgery

NASA Astrophysics Data System (ADS)

Cecchetti, Walter; Guazzieri, Stefano; Tasca, Andrea; Dal Bianco, M.; Zattoni, Filiberto; Pagano, Francesco

1996-12-01

The 980 nm Ceralas D50 diode laser, produces homogeneous lesions on tissues of different nature. In our endourological tests we used the Ceralas D50 coupled with Comeg 24 ch laser resectoscope, and we treated 22 patients: n.5 bladder cancers, n.3 uretero pelvic junction obstructions, with hydronephrosis, n.3 urethra stenosis, n1 ureter stenosis, n.4 multiple upper tract transitional cell carcinomas, n.6 BPH treatments with VLAP modalities. Using the 1000 micrometers delivery fibers with different shaped tips, we obtained a bloodless sharp cut and easily vaporizations with minimum carbonizations, with power output in the range of 8-12 W, and 18-24W for VLAP.

The Chicago Classification 3.0 Results in More Normal Findings and Fewer Hypotensive Findings With No Difference in Other Diagnoses.

PubMed

Monrroy, H; Cisternas, D; Bilder, C; Ditaranto, A; Remes-Troche, J; Meixueiro, A; Zavala, M A; Serra, J; Marín, I; Ruiz de León, A; Pérez de la Serna, J; Hani, A; Leguizamo, A; Abrahao, L; Coello, R; Valdovinos, M A

2017-04-01

High-resolution manometry (HRM) is the preferred method for the evaluation of motility disorders. Recently, an update of the diagnostic criteria (Chicago 3.0) has been published. The aim of this study was to compare the performance criteria of Chicago version 2.0 (CC2.0) vs. 3.0 (CC3.0) in a cohort of healthy volunteers and symptomatic patients. HRM studies of asymptomatic and symptomatic individuals from several centers of Spain and Latin America were analyzed using both CC2.0 and CC3.0. The final diagnosis was grouped into hierarchical categories: obstruction (achalasia and gastro-esophageal junction obstruction), major disorders (distal esophageal spasm, absent peristalsis, and jackhammer), minor disorders (failed frequent peristalsis, weak peristalsis with small or large defects, ineffective esophageal motility, fragmented peristalsis, rapid contractile with normal latency and hypertensive peristalsis) and normal. The results were compared using McNemar's and Kappa tests. HRM was analyzed in 107 healthy volunteers (53.3% female; 18-69 years) and 400 symptomatic patients (58.5% female; 18-90 years). In healthy volunteers, using CC2.0 and CC3.0, obstructive disorders were diagnosed in 7.5% and 5.6%, respectively, major disorders in 1% and 2.8%, respectively, minor disorders in 25.2% and 15%, respectively, and normal in 66.4% and 76.6%, respectively. In symptomatic individuals, using CC2.0 and CC3.0, obstructive disorders were diagnosed in 11% and 11.3%, respectively, major disorders in 14% and 14%, respectively, minor disorders in 33.3% and 24.5%, respectively, and normal in 41.8% and 50.3%, respectively. In both groups of individuals, only an increase in normal and a decrease in minor findings using CC3.0 were statistically significant using McNemar's test. CC3.0 increases the number of normal studies when compared with CC2.0, essentially at the expense of fewer minor disorders, with no significant differences in major or obstructive disorders. As the relevance of minor disorders is questionable, our data suggest that CC3.0 increases the relevance of abnormal results.

[Self-expanding antireflux stents for malignant esophageal stenosis - a report of three cases].

PubMed

Kusano-Kitazume, Akiko; Ami, Katsunori; Nagahama, Takeshi; Kondo, Mayumi; Okamoto, Eiko; Tamura, Atsushi; Takagi, Kentaro; Hayasaka, Junnosuke; Watanabe, Ayako; Kawai, Yosuke; Fujiya, Keiichi; Amagasa, Hidetoshi; Ganno, Hideaki; Imai, Kenichiro; Fukuda, Akira; Ando, Masayuki; Arai, Kuniyoshi; Shibayama, Takao

2014-11-01

Use of a standard open stent or self-expanding metal stent for patients with malignant dysphagia is associated with a risk of gastroesophageal reflux especially when placed across the esophagogastric junction. We report 3 cases of malignant esophageal stenosis treated with a long cover-type Niti-STM stent with an antireflux mechanism. Case 1: A 87-year-old man presented with dysphagia due to esophageal cancer at the middle thoracic esophagus. Two months after surgery using a standard open stent, the dysphagia relapsed because of tissue overgrowth. Case 2: A 73-year-old woman presented with lung cancer and severe dysphagia due to enlarged mediastinal lymph nodes. Case 3: A 66-year-old man presented with dysphagia due to esophageal cancer at the lower thoracic esophagus. All 3 patients received an antireflux stent across the esophagogastric junction. In cases 1 and 2, dysphagia was relieved immediately without complications. In case 3, the patient experienced severe reflux and chest pain associated with stent placement and could not ingest any solid food. We conclude that the antireflux stent may be useful for palliation in patients with severe malignant esophageal obstruction; however, patients should be informed about the risk of failure to prevent reflux.

Gastrointestinal manifestations of mitochondrial disorders: a systematic review

PubMed Central

Finsterer, Josef; Frank, Marlies

2016-01-01

Mitochondrial disorders (MIDs) due to respiratory-chain defects or nonrespiratory chain defects are usually multisystem conditions [mitochondrial multiorgan disorder syndrome (MIMODS)] affecting the central nervous system (CNS), peripheral nervous system, eyes, ears, endocrine organs, heart, kidneys, bone marrow, lungs, arteries, and also the intestinal tract. Frequent gastrointestinal (GI) manifestations of MIDs include poor appetite, gastroesophageal sphincter dysfunction, constipation, dysphagia, vomiting, gastroparesis, GI pseudo-obstruction, diarrhea, or pancreatitis and hepatopathy. Rare GI manifestations of MIDs include dry mouth, paradontosis, tracheoesophageal fistula, stenosis of the duodeno-jejunal junction, atresia or imperforate anus, liver cysts, pancreas lipomatosis, pancreatic cysts, congenital stenosis or obstruction of the GI tract, recurrent bowel perforations with intra-abdominal abscesses, postprandial abdominal pain, diverticulosis, or pneumatosis coli. Diagnosing GI involvement in MIDs is not at variance from diagnosing GI disorders due to other causes. Treatment of mitochondrial GI disease includes noninvasive or invasive measures. Therapy is usually symptomatic. Only for myo-neuro-gastro-intestinal encephalopathy is a causal therapy with autologous stem-cell transplantation available. It is concluded that GI manifestations of MIDs are more widespread than so far anticipated and that they must be recognized as early as possible to initiate appropriate diagnostic work-up and avoid any mitochondrion-toxic treatment. PMID:28286566

Renal Artery Embolization - A First Line Treatment Option For End-Stage Hydronephrosis

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

Mitra, Kakali; Prabhudesai, Vikramaditya; James, R. Lester

Conventionally poorly functioning hydronephrotic kidneys have been removed if they are symptomatic. In our unit, patients are offered renal artery embolization as an alternative treatment option. Patients and Methods: Fifteen patients (11 male, 4 female) with a mean age of 32.9 yr (20-51 yrs) have undergone renal artery embolization for symptomatic hydronephrosis with poor function. Mean follow-up was 64.13 weeks (range 14-200). All patients had loin pain and hydronephrosis. Twelve patients had primary pelvi-ureteric junction obstruction (PUJO). Two patients had poorly functioning hydronephrotic kidneys secondary to chronic calculous obstruction. One patient had chronic pain in an obstructed but reasonably functioningmore » kidney following a previous pyeloplasty for PUJO which demanded intervention. Mean split function on renography was 11% (range 0-46%). Selective renal artery embolization was carried out under antibiotic cover using a 7 Fr balloon occlusion catheter and absolute alcohol, steel coils, and polyvinyl alcohol particles.Results: Nine patients developed post-embolization syndrome of self-limiting pain and pyrexia with no evidence of sepsis. One patient required readmission with this condition. One patient developed a hematoma at the puncture site. Mean hospital stay was 2.3 days. Fourteen patients are happy with the result and are completely pain free. One patient has minor discomfort but is delighted with the result. Nine patients have had follow-up ultrasound confirming resolution of the hydronephrosis. Conclusion: Renal artery embolization is an effective, safe, well-tolerated minimally invasive treatment option in end-stage hydronephrosis and we routinely offer it as an alternative to nephrectomy.« less

[Urinary ascites, uroperitoneum and urinary peritonitis in children: management of nine case reports in Madagascar].

PubMed

Raherinantenaina, F; Rambel, A H; Rakotosamimanana, J; Rajaonanahary, T M A; Rajaonera, T; Rakototiana, F A; Hunald, F A; Andriamanarivo, M L; Rantomalala, H Y H; Rakoto Ratsimba, H N

2013-10-01

To evaluate the frequency of urinary peritonitis in children and to highlight its terms of management in a country with limited resources. We retrospectively observed nine case reports of urinary peritonitis collected in surgical reanimation service at the CHU of Antananarivo, from 1st January 2009 to 31 December 2012. Urinary peritonitis accounts 0.5% of all pediatric abdominal emergencies and 5% of pediatric urological emergencies collected in our service during study period. Three etiologies were traumatic bladder rupture, one bladder iatrogenic rupture, four secondary to obstructive uropathy and one other after cystolithotomy. We found a new case of posttraumatic transverse rupture of the bladder neck. Among obstructive uropathy observed, there were two cases of posterior urethral valves and two cases of ureteralpelvic junction obstruction. Clinical expression was dominated by fever, with abdominal distention and defense. In majority of cases, etiological diagnosis was made intraoperatively. The surgical treatment by laparotomy was performed under cover of systemic antibiotic therapy. Evolution was complicated with sepsis in three cases and acute renal failure in both cases. Surgical follow-up without complication were observed in four cases. A child has died to septic shock and multivisceral failure. Unlike urinary ascites resulting a transperitoneal extravasation of urine, uroperitoneum was a fistula between adominal cavity and content of the urinary tract. Urinary ascites was a rare cause of peritonitis. In contrast, uroperitoneum caused peritonitis quickly. Urinary peritonitis was a rare entity but severe prognosis in children. In majority of cases, etiological diagnosis was made intraoperatively. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Acute recurrent pancreatitis: Etiopathogenesis, diagnosis and treatment

PubMed Central

Testoni, Pier Alberto

2014-01-01

Acute recurrent pancreatitis (ARP) refers to a clinical entity characterized by episodes of acute pancreatitis which occurs on more than one occasion. Recurrence of pancreatitis generally occurs in a setting of normal morpho-functional gland, however, an established chronic disease may be found either on the occasion of the first episode of pancreatitis or during the follow-up. The aetiology of ARP can be identified in the majority of patients. Most common causes include common bile duct stones or sludge and bile crystals; sphincter of oddi dysfunction; anatomical ductal variants interfering with pancreatic juice outflow; obstruction of the main pancreatic duct or pancreatico-biliary junction; genetic mutations; alcohol consumption. However, despite diagnostic technologies, the aetiology of ARP still remains unknown in up to 30% of cases: in these cases the term “idiopathic” is used. Because occult bile stone disease and sphincter of oddi dysfunction account for the majority of cases, cholecystectomy, and eventually the endoscopic biliary and/or pancreatic sphincterotomy are curative in most of cases. Endoscopic biliary sphincterotomy appeared to be a curative procedure per se in about 80% of patients. Ursodeoxycholic acid oral treatment alone has also been reported effective for treatment of biliary sludge. In uncertain cases toxin botulin injection may help in identifying some sphincter of oddi dysfunction, but this treatment is not widely used. In the last twenty years, pancreatic endotherapy has been proven effective in cases of recurrent pancreatitis depending on pancreatic ductal obstruction, independently from the cause of obstruction, and has been widely used instead of more aggressive approaches. PMID:25493002

Continuous antibiotic prophylaxis reduces the risk of febrile UTI in children with asymptomatic antenatal hydronephrosis with either ureteral dilation, high-grade vesicoureteral reflux, or ureterovesical junction obstruction.

PubMed

Herz, Daniel; Merguerian, Paul; McQuiston, Leslie

2014-08-01

The efficacy and utility of continuous antibiotic prophylaxis (CAP) in children with congenital antenatal hydronephrosis (ANH) is uncertain. The literature has both supportive and contradictory evidence. The growing trend not to place children with ANH on CAP has created varied clinical practice based on anecdotal individual case characteristics. Our goal was to compare individual infant characteristics between those children who were maintained on CAP to those that were not to try to determine predisposing risk factors to febrile. All electronic medical records (EMRs) of children referred to our institution for congenital ANH over a period from 2001 to 2011 were examined. We excluded those referred for urinary tract infection (UTI) who had a history of congenital ANH. We also excluded those with incomplete records, or follow-up less than 2 years. Children were divided into two groups: those maintained on CAP (YCAP) and those not maintained on CAP (NCAP). Our primary endpoint was febrile UTI. Follow-up was at least 24 months. Demographic, perinatal and postnatal clinical data were recorded. Statistical analysis was performed using STATA Version 11.1. Of the 405 children fitting inclusion criteria, 278 (68.6%) children were maintained on CAP and 127 (31.4%) were not on CAP. The incidence of prematurity, oligohydramnios, perinatal respiratory complications, use of perinatal antibiotics, circumcision status, renal anomalies, associated medical diagnoses, and low birth weight did not differ between the two groups. Overall the incidence of febrile UTI during the follow-up period was 22.2%. The incidence of febrile UTI between the YCAP and NCAP groups was significant (YCAP = 7.9% and NCAP 18.7%, p = 0.021). Multivariate logistic regression using CAP as the dichotomous dependent variable revealed that ureteral dilation, high-grade vesicoureteral reflux (VUR), and ureterovesical junction (UVJ) obstruction were independent risk factors for febrile UTI. More specifically, children with ureteral dilation >11 mm NOT maintained on CAP had a 5.54 (OR = 5.54; CI = 3.15-7.42, p = 0.001) fold increased risk of febrile UTI compared to those maintained on CAP. The presence of ureteral dilation, high grade VUR, and UVJ obstruction were independent risk factors for development of UTI in children with congenital ANH. Therefore CAP may have a significant role in reducing the risk of febrile UTI in children with ANH with those identifiable risk factors, but otherwise seems unnecessary. Copyright © 2014 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

First experiences of pediatric kidney transplantation in Sri Lanka.

PubMed

Abeysekera, C K; Gunasekara, W D V N; Abegunawardena, A; Buthpitiya, A G; Lamawansa, M D; Fernando, O; Goonasekera, C D A

2007-06-01

KT is the most effective therapeutic option for ESRF. We present our first experiences in a developing country. All children who underwent kidney transplantation since the inception of this program in July 2004 until 30 September 2005 were studied. Their demographic data, operative and peri-operative details, graft and host survival, and drug compliance are described here. Data were collected from patient records and nursing observation records. Eleven children were transplanted during this period (median recipient age 10.75 yr, range: 8-16). The median age of the donors was 41 yr (range: 38-45) and was the mother in eight, father in two and uncle in one. The median (range) follow-up period following transplantation was 12.5 months (7-12). The vascular anastomotic site was aorta and inferior vena cava in nine patients and the cold ischemia time was mean (s.d.) 1.9 h (0.96). All patients received steroids, cyclosporine and MMF for immunosuppression. Hypotension, heart failure and septicemia were common medical complications. Four were treated for acute rejection. Vascular anastomotic leak, burst abdomen, intestinal obstruction, intra-abdominal leak of supra pubic catheter and vesico-ureteric junction obstruction were surgical complications. There were no graft losses or deaths. Despite limited resources good outcomes are possible following renal transplantation in children in developing countries.

Retroperitoneal laparoscopic dismembered pyeloplasty with a novel technique of JJ stenting in children.

PubMed

Yu, Jianhua; Wu, Zhonghua; Xu, Youming; Li, Zhuo; Wang, Jiansong; Qi, Fan; Chen, Xiang

2011-09-01

• To report our experience with retroperitoneal laparoscopic dismembered pyeloplasty for pelvi-ureteric junction (PUJ) obstruction in children. • Between March 2007 and December 2009, 38 children with PUJ obstruction (mean age 8.3 years, range 3-14) underwent retroperitoneal laparoscopic dismembered pyeloplasty. • A ureteric catheter was inserted into the mid-ureter cystoscopically. During pyeloplasty, the proximal end of the ureteric catheter was extracorporeally sutured to the distal end of the JJ stent with silk. • The ureteric catheter was then pulled down and the stent was pulled antegrade into the ureter and bladder. • The approach was retroperitoneal in all patients except one who required open conversion. The overall mean operative time was 162 min (range 145-210 min) and this appeared to decrease with experience. Mean hospital stay was 4 days (range 3-7 days). • Mean follow-up was 20.2 months (range 6-32 months). Satisfactory drainage with decreased hydronephrosis was documented in all patients on ultrasonography and intravenous urography. • Our study shows that retroperitoneal laparoscopic dismembered pyeloplasty is a feasible and effective alternative to open pyeloplasty with a relatively minimal complication rate in children 3 years of age and older, but it should be undertaken by experienced laparoscopic surgeons. © 2011 THE AUTHORS. BJU INTERNATIONAL © 2011 BJU INTERNATIONAL.

Extreme hydronephrosis due to uretropelvic junction obstruction in infant (case report).

PubMed

Krzemień, Grażyna; Szmigielska, Agnieszka; Bombiński, Przemysław; Barczuk, Marzena; Biejat, Agnieszka; Warchoł, Stanisław; Dudek-Warchoł, Teresa

2016-01-01

Hydronephrosis is the one of the most common congenital abnormalities of urinary tract. The left kidney is more commonly affected than the right side and is more common in males. To determine the role of ultrasonography, renal dynamic scintigraphy and lowerdose computed tomography urography in preoperative diagnostic workup of infant with extreme hydronephrosis. We presented the boy with antenatally diagnosed hydronephrosis. In serial, postnatal ultrasonography, renal scintigraphy and computed tomography urography we observed slightly declining function in the dilated kidney and increasing pelvic dilatation. Pyeloplasty was performed at the age of four months with good result. Results of ultrasonography and renal dynamic scintigraphy in child with extreme hydronephrosis can be difficult to asses, therefore before the surgical procedure a lower-dose computed tomography urography should be performed.

Giant hydronephrosis in a case of ureterocele with duplex system: an entity yet not reported.

PubMed

Aeron, Ruchir; Sokhal, Ashok Kumar; Kumar, Manoj; Sankhwar, Satyanarayan

2017-08-10

Ureterocele, which is a cystic dilatation of the terminal ureter, is usually associated with the upper moiety in a case of the duplex system. Giant hydronephrosis, a rare entity, is usually due to pelviureteric junction obstruction and is usually diagnosed in infants and children. We report a unique case of a unilateral complete duplex system with ureterocele with giant hydronephrosis of the upper moiety in an adult woman presenting as an abdominal lump. To the best of our knowledge, this is the first case of giant hydronephrosis associated with ureterocele in an adult patient. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Esophageal achalasia: current diagnosis and treatment.

PubMed

Schlottmann, Francisco; Patti, Marco G

2018-05-27

Esophageal achalasia is a primary esophageal motility disorder of unknown origin, characterized by lack of peristalsis and by incomplete or absent relaxation of the lower esophageal sphincter in response to swallowing. The goal of treatment is to eliminate the functional obstruction at the level of the gastroesophageal junction Areas covered: This comprehensive review will evaluate the current literature, illustrating the diagnostic evaluation and providing an evidence-based treatment algorithm for this disease Expert commentary: Today we have three very effective therapeutic modalities to treat patients with achalasia - pneumatic dilatation, per-oral endoscopic myotomy and laparoscopic Heller myotomy with fundoplication. Treatment should be tailored to the individual patient, in centers where a multidisciplinary approach is available. Esophageal resection should be considered as a last resort for patients who have failed prior therapeutic attempts.

Intradural pathology and pathophysiology associated with Chiari I malformation in children and adults with and without syringomyelia.

PubMed

Dlouhy, Brian J; Dawson, Jeffrey D; Menezes, Arnold H

2017-12-01

OBJECTIVE The pathophysiology underlying tonsillar herniation and CSF obstruction in Chiari malformation Type I (CM-I) is unclear, and the cause of CM-I-associated syringomyelia is not well understood. A better understanding of this pathophysiology is important for an improved treatment strategy. Therefore, the authors sought to identify, characterize, and examine the intradural pathology and CSF flow pathophysiology in the posterior fossa and at the level of the foramen magnum that occurs in the setting of CM-I. They determined the incidence of these intradural findings and assessed differences across age, with the degree of tonsillar herniation, and in the presence and absence of syringomyelia. METHODS A prospective database initiated in March 2003 recorded all intraoperative findings during surgical treatment of children and adults with CM-I with or without syringomyelia. A total of 389 surgeries for CM-I were performed in 379 patients between March 2003 and June 2016. A total of 109 surgeries were performed in 109 patients with CM-I (without osseoligamentous abnormalities) in whom both a posterior fossa extradural and intradural decompression with duraplasty was performed (first-time intradural procedures). Using a surgical microscope, intradural pathology and obstruction of CSF channels were identified and assessed. Student t-tests and Fisher's exact tests compared groups in a series of univariate analyses, followed by multivariate logistic regression. RESULTS The following intradural pathological entities were observed (prevalence noted in parentheses). These include those that did not obstruct CSF flow channels: opacified arachnoid (33.0%), thickened arachnoid (3.7%), ischemic and gliotic tonsils (40.4%), tonsillar cysts (0.9%), and inferior descent of the fourth ventricle and cervicomedullary junction (CMJ) (78.0%). The following intradural pathological entities were observed to obstruct CSF flow channels: medialized tonsils (100%), tonsil overlying and obstructing the foramen of Magendie (21.1%), intertonsillar and tonsil to CMJ arachnoid adhesions (85.3%), vermian posterior inferior cerebellar artery branches obstructing the foramen of Magendie (43.1%), and arachnoid veils or webs obstructing or occluding the foramen of Magendie (52.3%). Arachnoid veils varied in type and were observed in 59.5% of patients with CM-I who had syringomyelia, which was significantly greater than the 33.3% of patients with CM-I without syringomyelia who had an arachnoid veil (p = 0.018). The presence of CM-I with an arachnoid veil had 3.22 times the odds (p = 0.013, 95% CI 1.29-8.07, by multivariate logistic regression) of being associated with syringomyelia, adjusting for tonsillar herniation. The inferior descent of the fourth ventricle and CMJ occurred with a greater degree of tonsillar herniation (p < 0.001) and correlated with a cervicomedullary kink or buckle on preoperative MRI. CONCLUSIONS Intradural pathology associated with CM-I with or without syringomyelia exists in many forms, is more prevalent than previously recognized in patients of all ages, and may play a role in the pathophysiology of CM-I tonsillar herniation. Arachnoid veils appear to partially obstruct CSF flow, are significantly more prevalent in cases of CM-I with syringomyelia, and therefore may play a role in the pathophysiology of CM-I-associated syringomyelia.

Novel design and fabrication of a geometrical obstacle-embedded micromixer with notched wall

NASA Astrophysics Data System (ADS)

Wu, Shih-Jeh; Hsu, Hsiang-Chen; Feng, Wen-Jui

2014-09-01

A microfluidic embedded MEMS mixer with a Y-junction type channel and cylindrical obstructions was designed and fabricated for improving the fluid mixing mechanism under low Reynolds number (\\mathit{Re}) condition. The flow field was simulated numerically by software (COMSOL multiphysics®) first. The design was then realized through casting the device in PDMS by lithographed SU-8 photo-resistive mold on silicon wafer. Parametric experimental studies were conducted for optimal design. Two different fluids were pumped into the two legs of the Y-junction channel, and the fluids were broken-up by an embedded cylindrical obstacle in the middle of the tapered micro-channel. The chaotic convection took place in the mixing channel behind the embedded cylindrical obstacles. The flow motion was observed under CCD camera and analyzed by grey level. The developed micromixer in this study can enhance the fluid mixing by the interaction of diffusion and convection for wide range of Reynolds numbers (0.01 < \\mathit{Re} < 100). Experimental results showed that the mixing index reached the required value at 0.1 within 0.024 seconds when the inlet fluid velocity is 0.499 m/s (i.e., at 1200 µl/min flow rate) for merely four cylindrical obstacles. A shorter mixing distance can be accomplished compared to the current devices reported due to faster mixing and shorter mixing time.

Belching, regurgitation, chest tightness and dyspnea: not gastroesophageal reflux disease but asthma.

PubMed

Zhang, Jing-Xi; Zhan, Xian-Bao; Bai, Chong; Li, Qiang

2015-02-07

Belching is a common symptom of gastroesophageal reflux disease. If the symptoms are not relieved after anti-reflux treatment, another etiology should be considered. Here, we report a case of a 43-year-old man who presented with belching, regurgitation, chest tightness and dyspnea for 18 mo, which became gradually more severe. Gastroscopic examination suggested superficial gastritis. Twenty-four-hour esophageal pH monitoring showed that the Demeester score was 11.4, in the normal range. High-resolution manometry showed that integrated relaxation pressure and intrabolus pressure were higher than normal (20 mmHg and 22.4 mmHg, respectively), indicating gastroesophageal junction outflow tract obstruction. Pulmonary function test showed severe obstructive ventilation dysfunction [forced expiratory volume in 1 second (FEV1)/forced vital capacity 32%, FEV1 was 1.21 L, occupying 35% predicted value after salbuterol inhalation], and positive bronchial dilation test (∆FEV1 260 mL, ∆FEV1% 27%). Skin prick test showed Dermatophagoides farinae (++), house dust mite (++++), and shrimp protein (++). Fractional exhaled nitric oxide measurement was 76 ppb. All the symptoms were alleviated completely and pulmonary function increased after combination therapy with corticosteroids and long-acting β2-agonist. Bronchial asthma was eventually diagnosed by laboratory tests and the effect of anti-asthmatic treatment, therefore, physicians, especially the Gastrointestinal physicians, should pay attention to the belching symptoms of asthma.

High resolution esophageal manometry--the switch from "intuitive" visual interpretation to Chicago classification.

PubMed

Srinivas, M; Balakumaran, T A; Palaniappan, S; Srinivasan, Vijaya; Batcha, M; Venkataraman, Jayanthi

2014-03-01

High resolution esophageal manometry (HREM) has been interpreted all along by visual interpretation of color plots until the recent introduction of Chicago classification which categorises HREM using objective measurements. It compares HREM diagnosis of esophageal motor disorders by visual interpretation and Chicago classification. Using software Trace 1.2v, 77 consecutive tracings diagnosed by visual interpretation were re-analyzed by Chicago classification and findings compared for concordance between the two systems of interpretation. Kappa agreement rate between the two observations was determined. There were 57 males (74 %) and cohort median age was 41 years (range: 14-83 years). Majority of the referrals were for gastroesophageal reflux disease, dysphagia and achalasia. By "intuitive" visual interpretation, the tracing were reported as normal in 45 (58.4 %), achalasia 14 (18.2 %), ineffective esophageal motility 3 (3.9 %), nutcracker esophagus 11 (14.3 %) and nonspecific motility changes 4 (5.2 %). By Chicago classification, there was 100 % agreement (Kappa 1) for achalasia (type 1: 9; type 2: 5) and ineffective esophageal motility ("failed peristalsis" on visual interpretation). Normal esophageal motility, nutcracker esophagus and nonspecific motility disorder on visual interpretation were reclassified as rapid contraction and esophagogastric junction (EGJ) outflow obstruction by Chicago classification. Chicago classification identified distinct clinical phenotypes including EGJ outflow obstruction not identified by visual interpretation. A significant number of unclassified HREM by visual interpretation were also classified by it.

A geriatric patient with diffuse idiopathic skeletal hyperostosis

PubMed Central

Karadag, Berrin; Cat, Huseyin; Aksoy, Selma; Ozulu, Banu; Ozturk, Ali Osman; Oguz, Sukru; Altuntas, Yuksel

2010-01-01

The most frequent health problems seen in senility are chronic and degenerative diseases. A 75-year-old male patient with the complaints of weight loss and difficulty in swallowing was admitted to our hospital from a nursing home. Upper system fiber-optic gastrointestinal endoscopy was performed and a mass at the junction of the hypopharynx and esophagus just below recessus piriformis obstructing almost the whole of the lumen and blocking the distal passage was detected. Computed tomography revealed marked narrowing secondary to osseous hypertrophy in the air column of the hypopharynx and proximal esophagus. Diffuse idiopathic skeletal hyperostosis or Forestier’s disease is an idiopathic disease characterized by the ossification of the anterior longitudinal ligament of vertebra and some of the extraspinal ligaments. In the present case we aim to discuss an elderly patient who suffered from dysphagia and weight loss and the diagnostic stages. PMID:20355249

Radionuclide studies of chronic schistosomal uropathy. [/sup 99m/Tc-DTPA; /sup 131/I-hippuran

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

Lamki, L.M.; Lamki, N.

1981-08-01

Fifty patients with chronic urinary tract schistosomiasis were studied with /sup 99m/Tc-DTPA. All had a flow study, sequential analog imaging, and digital imaging for 25 to 35 min (20-sec frames). Time-activity curves (DTPA renograms) were extracted; 12 patients had /sup 131/I-Hippuran probe renograms as well. Renal changes included diminished perfusion and structural abnormalities ranging from minor calyceal dilatation to overt hydronephrosis. Ureteral changes included dilatation, tortuosity, and kinking. Marked distortion of the ureterovesical junction was seen in some patients due to periureteral and perivesicular fibrosis, which is a major factor in upper urinary tract damage. Renograms showed varying obstruction andmore » parenchymal damage. Nuclear medicine complements excretory urography and is sometimes preferable for visualization of the ureters. After the initial urogram, sequential DTPA scanning and renography are sufficient for follow-up.« less

Diuretic 99mTc DTPA renography in assessment of renal function and drainage in infants with antenatally detected hydronephrosis.

PubMed

Radulović, Marija; Pucar, Dragan; Jauković, Ljiljana; Sisić, Marija; Krstić, Zoran; Ajdinović, Boris

2015-12-01

The controversy over the postnatal management of infants with antenataly detected hydronephrosis (ANH) still exists. We presented the results of diuretic 99mTc diethylenetriamine pentaacetic acid (DTPA) renography in 30 infants with the antenatal diagnosis of unilateral renal pelvic dilatation. The aim of this study was to assess the renal function determined by the pattern of drainage and split renal function (SRF) on diuretic renography and to correlate these findings with anteroposterior pelvic diameter (APD) estimated by ultrasonography. A total of 30 infants with 60 renal units (RU) (25 boys and 5 girls, median age 6.0 months, range 2-24) presented with unilateral hydronephrosis on ultrasound in the newborn period, underwent DTPA diuretic renal scintigraphy (F+15 protocol). The median APD evaluated on perinatal ultrasound was 15 mm (range 5-30). The postnatal associated clinical diagnosis were pelviureteric junction obstruction (PUJ), simple hydronephrosis, megaureter, vesicoureteral reflux (VUR) and posterior urethral valves in 11, 10, 6, 2 and 1 infant, respectively. Images and Tmax/2 after diuretic stimulation on the background subtracted renographic curves were used as the criteria for classifying the drainage as good, partial, and poor or no drainage. The SRF was calculated with the integral method. Good drainage was shown in 36/60, partial drainage in 13/60 and poor or no drainage in 11/60 RU. The SRF > 40% was observed in 55/60 RU, with no RU showing SRF lower than 23.5%. In infants with severe ANH the obstruction was not excluded in 94.1%. Diuretic renography in antenatally detected hydronephrosis should be a useful tool in postnatal follow up, especially in differentiating nonobstructive hydronephrosis from obstructive. It is also importanat to assess and monitor the SRF. Our results suggest that even in the presence of partial or no drainage, SRF may not be significantly impaired.

Surgical treatment reduces blood pressure in children with unilateral congenital hydronephrosis.

PubMed

Al-Mashhadi, Ammar; Nevéus, Tryggve; Stenberg, Arne; Karanikas, Birgitta; Persson, A Erik G; Carlström, Mattias; Wåhlin, Nils

2015-04-01

Renal disorders can cause hypertension, but less is known about the influence of hydronephrosis on blood pressure. Hydronephrosis due to pelvo-ureteric junction obstruction (PUJO) is a fairly common condition (incidence in newborns of 0.5-1%). Although hypertensive effects of hydronephrosis have been suggested, this has not been substantiated by prospective studies in humans [1-3]. Experimental studies with PUJO have shown that animals with induced hydronephrosis develop salt-sensitive hypertension, which strongly correlate to the degree of obstruction [4-7]. Moreover, relief of the obstruction normalized blood pressure [8]. In this first prospective study our aim was to study the blood pressure pattern in pediatric patients with hydronephrosis before and after surgical correction of the ureteral obstruction. Specifically, we investigated if preoperative blood pressure is reduced after surgery and if split renal function and renographic excretion curves provide any prognostic information. Twelve patients with unilateral congenital hydronephrosis were included in this prospective study. Ambulatory blood pressure (24 h) was measured preoperatively and six months after surgery. Preoperative evaluations of bilateral renal function by Tc99m-MAG3 scintigraphy, and renography curves, classified according to O'Reilly, were also performed. As shown in the summary figure, postoperative systolic (103 ± 2 mmHg) and diastolic (62 ± 2 mmHg) blood pressure were significantly lower than those obtained preoperatively (110 ± 4 and 69 ± 2 mmHg, respectively), whereas no changes in circadian variation or pulse pressure were observed. Renal functional share of the hydronephrotic kidney ranged from 11 to 55%. There was no correlation between the degree of renal function impairment and the preoperative excretory pattern, or between the preoperative excretory pattern and the blood pressure reduction postoperatively. However, preoperative MAG3 function of the affected kidney correlated with the magnitude of blood pressure change after surgery. Correction of the obstruction lowered blood pressure, and the reduction in blood pressure appeared to correlate with the degree of renal functional impairment, but not with the excretory pattern. Thus, in the setting of hypertension, it appears that the functional share of the hydronephrotic kidney should be considered an indicator of the need for surgery, whereas the renography curve is less reliable. The strength of the present study is the prospective nature and that ambulatory blood pressure monitoring was used. Future longitudinal prolonged follow-up studies are warranted to confirm the present findings, and to understand if a real nephrogenic hypertension with potential necessity of treatment will develop. This novel prospective study in patients with congenital hydronephrosis demonstrates a reduction in blood pressure following relief of the obstruction. Based on the present results, we propose that the blood pressure level should also be taken into account when deciding whether to correct hydronephrosis surgically or not. Copyright © 2015 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

Development of Hairpin Vortices in Turbulent Spots and End-Wall Transition

NASA Technical Reports Server (NTRS)

Smith, Charles R.

2007-01-01

The end-stage phase of boundary layer transition is characterized by the development of hairpin-like vortices which evolve rapidly into patches of turbulent behavior. In general, the characteristics of the evolution form this hairpin stage to the turbulent stage is poorly understood, which has prompted the present experimental examination of hairpin vortex development and growth processes. Two topics of particular relevance to the workshop focus will be covered: 1) the growth of turbulent spots through the generatio and amalgamation of hairpin-like vortices, and 2) the development of hairpin vortices during transition in an end-wall junction flow. Brief summaries of these studies are described below. Using controlled generation of hairpin vortices by surface injection in a critical laminar boundary layer, detailed flow visualization studies have been done of the phases of growth of single hairpin vortices, from the initial hairgin generation, through the systematic generation of secondary hairpin-like flow structures, culminating in the evolution to a turbulent spot. The key to the growth process is strong vortex-surface interactions, which give rise to strong eruptive events adjacent to the surface, which results in the generation of subsequent hairpin vortex structures due to inviscid-viscuous interactions between the eruptive events and the free steam fluid. The general process of vortex-surface fluid interaction, coupled with subsequent interactions and amalgamation of the generated multiple hairpin-type vortices, is demonstrated as a physical mechanism for the growth and development of turbulent spots. When a boundary layer flow along a surface encounters a bluff body obstruction extending from the surface (such as cylinder or wing), the strong adverse pressure gradients generated by these types of flows result in the concentration of the impinging vorticity into a system of discrete vortices near the end-wall juncture of the obstruction, with the extensions of the vortices engirdling the obstruction to form "necklace" or "horseshoe" vortices. Recent hydrogen bubble and particle image visualization have shown that as Reynolds number is increased for a laminar approach flow, the flow will become critical, and a destabilization of the necklace vortices results in the development of an azimuthal waviness, or "kinks", in the vortices. These vortex kinks are accentuated by Biot-Savart effects, causing portions of a distorted necklace vortex to make a rapid approach to the surface, precipitating processes of localized, three-dimensional surface interactions. These interactions result in the rapid generation, focussing, and ejection of thin tongues of surface fluid, which rapidly roll-over and appear as hairpin vortices in the junction region. Subsequent amalgamation of these hairpin vortices with the necklace vortices produces a complex transitional-type flow. A presentation of key results from both these studies will be done, emphasizing both the ubiquity of such hairpin-type flow structures in manifold transitional-type flows, and the importance of vortex-surface interactions n the development of hairpin vortices.

Site of impaction of ureteric calculi requiring surgical intervention.

PubMed

El-Barky, Ehab; Ali, Yusuf; Sahsah, Mohammed; Terra, Ali A; Kehinde, Elijah O

2014-02-01

Textbooks describe three narrowest anatomic sites in the ureter as the most likely places for ureteral calculi to lodge, these are: the pelvi-ureteric junction (PUJ), the point where the ureters cross over the iliac vessels and the ureterovesical junction (UVJ). The purpose of this study is to determine whether calculi causing ureteric obstruction and requiring surgical treatment are found mostly at these three narrowest anatomic points of the ureter. Three hundred consecutive patients with impacted ureteric calculi who required surgical intervention were studied. The location of the impacted calculus on the day of surgical intervention was categorized according to nine predetermined levels outlined in a designed diagram based on findings on non-contrast CT of kidneys, ureters and bladder. Two peaks in stone distribution in the ureters were encountered; the first was above the ischial spine in the proximal part of the lower third ureter (84 patients, 28%), while the second was at the level between L3 and L4 lumbar vertebrae (66 patients, 22%). Overall, the location of impacted calculi was as follows, 53, 34, 10 and 3% in the lower third ureter, upper third ureter, PUJ and mid ureter, respectively. This study demonstrates two peaks of calculi distribution in the ureter where ureteric calculi become impacted: the upper ureter below the PUJ and a second in the lower ureter, more proximal than the UVJ. There was an absence of the peak in stone location over the iliac vessels, that is, the mid ureter.

Hydrocephalus due to multiple ependymal malformations is caused by mutations in the MPDZ gene.

PubMed

Saugier-Veber, Pascale; Marguet, Florent; Lecoquierre, François; Adle-Biassette, Homa; Guimiot, Fabien; Cipriani, Sara; Patrier, Sophie; Brasseur-Daudruy, Marie; Goldenberg, Alice; Layet, Valérie; Capri, Yline; Gérard, Marion; Frébourg, Thierry; Laquerrière, Annie

2017-05-01

Congenital hydrocephalus is considered as either acquired due to haemorrhage, infection or neoplasia or as of developmental nature and is divided into two subgroups, communicating and obstructive. Congenital hydrocephalus is either syndromic or non-syndromic, and in the latter no cause is found in more than half of the patients. In patients with isolated hydrocephalus, L1CAM mutations represent the most common aetiology. More recently, a founder mutation has also been reported in the MPDZ gene in foetuses presenting massive hydrocephalus, but the neuropathology remains unknown. We describe here three novel homozygous null mutations in the MPDZ gene in foetuses whose post-mortem examination has revealed a homogeneous phenotype characterized by multiple ependymal malformations along the aqueduct of Sylvius, the third and fourth ventricles as well as the central canal of the medulla, consisting in multifocal rosettes with immature cell accumulation in the vicinity of ependymal lining early detached from the ventricular zone. MPDZ also named MUPP1 is an essential component of tight junctions which are expressed from early brain development in the choroid plexuses and ependyma. Alterations in the formation of tight junctions within the ependyma very likely account for the lesions observed and highlight for the first time that primary multifocal ependymal malformations of the ventricular system is genetically determined in humans. Therefore, MPDZ sequencing should be performed when neuropathological examination reveals multifocal ependymal rosette formation within the aqueduct of Sylvius, of the third and fourth ventricles and of the central canal of the medulla.

'Targeted top down' approach for the investigation of UTI: A 10-year follow-up study in a cohort of 1000 children.

PubMed

Broadis, E; Kronfli, R; Flett, M E; Cascio, S; O'Toole, S J

2016-02-01

Investigations following urinary tract infection (UTI) aim to identify children who are prone to renal scarring, which may be preventable. In 2002, in an attempt to reduce unnecessary intervention, the present institution standardised the investigation of children with a confirmed UTI. This study aimed to identify the significance of urological abnormalities on investigations following a UTI in children, prior to the introduction of the National Institute for Health and Care Excellence (NICE) guidelines. Clinical information on the first 1000 patients was retrieved from a prospective UTI hospital database. The follow-up period was 10 years. There were 180 males and 820 females (M:F = 1:4.5). The median age of presentation was 5 years (range 11 days-16 years). A renal ultrasound (US) was performed on all patients, and was normal in 93% of cases (n = 889) (see Figure). Of the 7% who had an abnormal US (n = 71), 54 were female and 17 male (M:F = 1:3). A total of 372 DMSA scans were requested and 350 attended their appointment. Of these, 278 cases (79%) were reported as normal, while 72 had an abnormality documented. Of these 72 patients with abnormalities on DMSA scan, 49 had a repeat DMSA scan: 30 demonstrated permanent scarring, while the DMSA scan became normal in 19. Sixteen of the 278 patients whose DMSA scan was initially normal had a repeat DMSA scan due to symptoms, and all scans were normal. Twelve (1.2%) patients required surgical intervention: three underwent circumcision for recurrent UTIs; three underwent endoscopic treatment of VUR; one had a PUV resection; one underwent a cystoscopy; three had a pyeloplasty for pelvi-ureteric junction obstruction; and one had a ureteric reimplantation for vesico-ureteric junction obstruction. After initial investigations and management, 936 patients were discharged from the UTI clinic: 47 of them re-presented - 40 with recurrent UTIs and seven with dysuria. Thirty-five of the 47 children who re-presented with urological symptoms underwent a DMSA scan, which showed scarring in three (6%). Only 12% of children have a significant radiological abnormality picked up on investigation following a UTI. The present investigation approach differed from the NICE guidelines, where imaging is based on patient age and characteristics of the UTI. All children had a renal US, while DMSA scans were reserved for those children <1 year of age or those with upper tract symptoms. The present protocol recommended a renal US in all children presenting with a UTI. This promptly identified those with pelvi-ureteric junction obstruction and those with PUV, who all presented >6 months of age with a single UTI and, therefore, based on the NICE guidelines would not have undergone a renal US. Of the children who re-presented with further UTIs, a significant number were found to have dysfunctional voiding. As this link is well reported, it may be appropriate to screen for this in older children at initial presentation. Only three patients, who had a US at presentation, were subsequently found to have scarring on DMSA. After 10 years of follow-up, this could represent a false negative rate of 0.3% for the screening programme. None of the girls were found to have VUR or needed any surgical intervention, which suggested that early identification of the scarring might not have altered management. Few patients required surgical intervention, all of whom were identified early. No patient who re-presented required intervention. This would suggest that the present protocol is effective at picking up abnormalities that require surgical management. This study suggested that after a childhood UTI, the liberal use of renal ultrasound and a focused 'top down' approach to investigation is likely to identify the vast majority of children who require intervention. Copyright © 2015 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

Evaluation of Esophageal Motility Utilizing the Functional Lumen Imaging Probe.

PubMed

Carlson, Dustin A; Kahrilas, Peter J; Lin, Zhiyue; Hirano, Ikuo; Gonsalves, Nirmala; Listernick, Zoe; Ritter, Katherine; Tye, Michael; Ponds, Fraukje A; Wong, Ian; Pandolfino, John E

2016-12-01

Esophagogastric junction (EGJ) distensibility and distension-mediated peristalsis can be assessed with the functional lumen imaging probe (FLIP) during a sedated upper endoscopy. We aimed to describe esophageal motility assessment using FLIP topography in patients presenting with dysphagia. In all, 145 patients (aged 18-85 years, 54% female) with dysphagia that completed upper endoscopy with a 16-cm FLIP assembly and high-resolution manometry (HRM) were included. HRM was analyzed according to the Chicago Classification of esophageal motility disorders; major esophageal motility disorders were considered "abnormal". FLIP studies were analyzed using a customized program to calculate the EGJ-distensibility index (DI) and generate FLIP topography plots to identify esophageal contractility patterns. FLIP topography was considered "abnormal" if EGJ-DI was <2.8 mm 2 /mm Hg or contractility pattern demonstrated absent contractility or repetitive, retrograde contractions. HRM was abnormal in 111 (77%) patients: 70 achalasia (19 type I, 39 type II, and 12 type III), 38 EGJ outflow obstruction, and three jackhammer esophagus. FLIP topography was abnormal in 106 (95%) of these patients, including all 70 achalasia patients. HRM was "normal" in 34 (23%) patients: five ineffective esophageal motility and 29 normal motility. In all, 17 (50%) had abnormal FLIP topography including 13 (37%) with abnormal EGJ-DI. FLIP topography provides a well-tolerated method for esophageal motility assessment (especially to identify achalasia) at the time of upper endoscopy. FLIP topography findings that are discordant with HRM may indicate otherwise undetected abnormalities of esophageal function, thus FLIP provides an alternative and complementary method to HRM for evaluation of non-obstructive dysphagia.

Bacterial characteristics and clinical significance of ureteral double-J stents in children.

PubMed

García-Aparicio, L; Blázquez-Gómez, E; Martin, O; Krauel, L; de Haro, I; Rodó, J

2015-01-01

To determine the incidence of urinary tract infection in those patients that we have used an ureteral double-J stent as internal diversion after urological procedures. We reviewed all the medical records of patients who had a ureteral double-J stent after a urological procedure from August 2007 to May 2013. We have analyzed the following data: age, gender, type of prophylaxis, incidence of urinary tract infection (UTI), days of internal diversion with double-J stent, surgical procedure, bacterial characteristics, bacterial sensibility to antibiotics and UTI treatment. We have used 73 double-J stents as ureteral internal diversion in 67 patients with a mean age of 44.73±57.23. Surgical procedures were 50 laparoscopic Anderson-Hynes pyeloplasties in 49 patients, and 20 high-pressure balloon dilatation of the ureterovesical junction to treat primary obstructive megaureter in 15 patients; and 3 patients with ureterovesical obstruction after endoscopic treatment of vesicoureteral reflux. Forty three stents showed a bacterial colonization in cultures. Pseudomona aeruginosa was present in 9 (20.9%) stents. Only in 12 stents, bacterial colonization was sensible to antibiotic prophylaxis. Stent colonization was higher in boys and younger patients. Four patients had a febrile UTI. Incidence of UTI in younger patients that underwent HBPD of UVJ is higher. Bacterial colonization is frequent in double-J stents but the incidence of UTI is low. Double-J colonization is higher in younger patients. Patients that underwent HPBD have a higher risk of UTI related with ureteral double J stent. Copyright © 2014 AEU. Publicado por Elsevier España, S.L.U. All rights reserved.

Evaluation of esophageal motility utilizing the functional lumen imaging probe (FLIP)

PubMed Central

Carlson, Dustin A.; Kahrilas, Peter J.; Lin, Zhiyue; Hirano, Ikuo; Gonsalves, Nirmala; Listernick, Zoe; Ritter, Katherine; Tye, Michael; Ponds, Fraukje A.; Wong, Ian; Pandolfino, John E.

2016-01-01

Background Esophagogastric junction (EGJ) distensibility and distension-mediated peristalsis can be assessed with the functional lumen imaging probe (FLIP) during a sedated upper endoscopy. We aimed to describe esophageal motility assessment using FLIP topography in patients presenting with dysphagia. Methods 145 patients (ages 18 – 85, 54% female) with dysphagia that completed upper endoscopy with a 16-cm FLIP assembly and high-resolution manometry (HRM) were included. HRM was analyzed according to the Chicago Classification of esophageal motility disorders; major esophageal motility disorders were considered ‘abnormal’. FLIP studies were analyzed using a customized program to calculate the EGJ-distensibility index (DI) and generate FLIP topography plots to identify esophageal contractility patterns. FLIP topography was considered ‘abnormal’ if EGJ-DI was < 2.8 mm2/mmHg or contractility pattern demonstrated absent contractility or repetitive, retrograde contractions. Results HRM was abnormal in 111 (77%) patients: 70 achalasia (19 type I, 39 type II, 12 type III), 38 EGJ outflow obstruction, and three jackhammer esophagus. FLIP topography was abnormal in 106 (95%) of these patients, including all 70 achalasia patients. HRM was ‘normal’ in 34 (23%) patients: five ineffective esophageal motility and 29 normal motility. 17 (50%) had abnormal FLIP topography including 13 (37%) with abnormal EGJ-DI. Conclusions FLIP topography provides a well-tolerated method for esophageal motility assessment (especially to identify achalasia) at the time of upper endoscopy. FLIP topography findings that are discordant with HRM may indicate otherwise undetected abnormalities of esophageal function, thus FLIP provides an alternative and complementary method to HRM for evaluation of non-obstructive dysphagia. PMID:27725650

Induction of mesenchymal cell phenotypes in lung epithelial cells by adenovirus E1A.

PubMed

Behzad, A R; Morimoto, K; Gosselink, J; Green, J; Hogg, J C; Hayashi, S

2006-12-01

Epithelial-mesenchymal transformation is now recognised as an important feature of tissue remodelling. The present report concerns the role of adenovirus infection in inducing this transformation in an animal model of chronic obstructive pulmonary disease. Guinea pig primary peripheral lung epithelial cells (PLECs) transfected with adenovirus E1A (E1A-PLECs) were compared to guinea pig normal lung fibroblasts (NLFs) transfected with E1A (E1A-NLFs). These cells were characterised by PCR, immunocytochemistry, electron microscopy, and Western and Northern blot analyses. Electrophoretic mobility shift assays were performed in order to examine nuclear factor (NF)-kappaB and activator protein (AP)-1 binding activities. E1A-PLECs and E1A-NLFs positive for E1A DNA, mRNA and protein expressed cytokeratin and vimentin but not smooth muscle alpha-actin. Both exhibited cuboidal morphology and junctional complexes, but did not contain lamellar bodies or express surfactant protein A, B or C mRNAs. These two cell types differed, however, in their NF-kappaB and AP-1 binding after lipopolysaccharide stimulation, possibly due to differences in the expression of the subunits that comprise these transcriptional complexes. E1A transfection results in the transformation of peripheral lung epithelial cells and normal lung fibroblasts to a phenotype intermediate between that of the two primary cells. It is postulated that this intermediate phenotype may play a major role in the remodelling of the airways in chronic obstructive pulmonary disease associated with persistence of adenovirus E1A DNA.

Exploratory Research on Latent Esophageal Motility Disorders in Dysphagia Patients.

PubMed

Kawaguchi, Shinpei; Takeuchi, Toshihisa; Inoue, Yousuke; Takahashi, Yoshiaki; Ozaki, Haruhiko; Ota, Kazuhiro; Harada, Satoshi; Edogawa, Shoko; Kojima, Yuichi; Yamashita, Hiroshi; Fukuchi, Takumi; Ashida, Kiyoshi; Higuchi, Kazuhide

2017-01-01

High-resolution manometry (HRM) has been applied to assess esophageal motility disorders. However, the frequency and types of motility disorders in patients with dysphagia, which are frequently seen in clinical practice, are not clear. We evaluated latent esophageal motility disorders associated with dysphagia. The study included patients without erosive esophageal mucosal damage and with dysphagia symptoms refractory to at least 8 weeks of standard-dose proton pump inhibitors. After enrolment, HRM was used to evaluate for esophageal motility disorder based on the Chicago classification. Esophageal motility disorder was found in 58 of 100 patients and was classified based on the causes: achalasia (13%), esophagogastric junction outflow obstruction (16%), distal esophageal spasms (3%), weak peristalsis (14%), frequently failed peristalsis (5%), and hypertensive peristalsis (7%). Primary esophageal motility disorder was found in approximately 50% of cases in dysphagia patients. Therefore, esophageal motility disorder is not an uncommon condition and should be sought for in order to elucidate precisely the cause of dysphagia. © 2017 S. Karger AG, Basel.

A pictorial presentation of 3.0 Chicago Classification for esophageal motility disorders.

PubMed

Herbella, Fernando Augusto; Armijo, Priscila Rodrigues; Patti, Marco Giuseppe

2016-01-01

High resolution manometry changed several esophageal motility paradigms. The 3.0 Chicago Classification defined manometric criteria for named esophageal motility disorders. We present a pictorial atlas of motility disorders. Achalasia types, esophagogastric junction obstruction, absent contractility, distal esophageal spasm, hypercontractile esophagus (jackhammer), ineffective esophageal motility, and fragmented peristalsis are depicted with high-resolution manometry plots. RESUMO A manometria de alta resolução mudou vários paradigmas da motilidade digestiva. A Classificação de Chicago, na versão 3.0, definiu critérios manométricos para as doenças da motilidade esofagiana. O presente artigo é um atlas das dismotilidades descritas. Tipos de acalásia, obstrução ao nível da junção esofagogástrica, contrações ausentes, espasmo esofagiano distal, esôfago hipercontrátil, motilidade esofagiana ineficaz e peristalse fragmentada são mostradas em traçados de manometria de alta resolução.

Application of Pyridostigmine in Pediatric Gastrointestinal Motility Disorders: A Case Series.

PubMed

Manini, Mhd Louai; Camilleri, Michael; Grothe, Rayna; Di Lorenzo, Carlo

2018-04-01

Gastrointestinal (GI) motility disorders are common in children. Treatment is challenging with limited medical and surgical options. Pyridostigmine, an acetyl cholinesterase inhibitor, increases acetylcholine at the neuromuscular junction promoting intestinal contractions. Little is known about the role and dosing of pyridostigmine in pediatric GI motility disorders. We present a case series of children with GI dysmotility managed with oral pyridostigmine. Patients' diagnoses include chronic intestinal pseudo-obstruction, gastroparesis with delayed small bowel transit, chronic constipation with failure to thrive, and prolonged ileus after pelvic surgery with chronic opioid use. Pyridostigmine was effective and safe in all cases. Pyridostigmine decreased abdominal distention, increased bowel movement frequency, and improved enteral feeding tolerance. Effective dosing ranged between 0.25-2.0 mg/kg/day. One patient experienced cramping abdominal pain while on pyridostigmine, but pain resolved after medication was discontinued. We found oral pyridostigmine to be helpful in children with different GI motility problems. Pyridostigmine should be considered in such patients when other treatment interventions have not been beneficial.

Epithelial adhesion molecules and the regulation of intestinal homeostasis during neutrophil transepithelial migration

PubMed Central

Sumagin, Ronen; Parkos, Charles A

2014-01-01

Epithelial adhesion molecules play essential roles in regulating cellular function and maintaining mucosal tissue homeostasis. Some form epithelial junctional complexes to provide structural support for epithelial monolayers and act as a selectively permeable barrier separating luminal contents from the surrounding tissue. Others serve as docking structures for invading viruses and bacteria, while also regulating the immune response. They can either obstruct or serve as footholds for the immune cells recruited to mucosal surfaces. Currently, it is well appreciated that adhesion molecules collectively serve as environmental cue sensors and trigger signaling events to regulate epithelial function through their association with the cell cytoskeleton and various intracellular adapter proteins. Immune cells, particularly neutrophils (PMN) during transepithelial migration (TEM), can modulate adhesion molecule expression, conformation, and distribution, significantly impacting epithelial function and tissue homeostasis. This review discusses the roles of key intestinal epithelial adhesion molecules in regulating PMN trafficking and outlines the potential consequences on epithelial function. PMID:25838976

Correlation Between Echodefecography and 3-Dimensional Vaginal Ultrasonography in the Detection of Perineal Descent in Women With Constipation Symptoms.

PubMed

Murad-Regadas, Sthela M; Pinheiro Regadas, Francisco Sergio; Rodrigues, Lusmar V; da Silva Vilarinho, Adjra; Buchen, Guilherme; Borges, Livia Olinda; Veras, Lara B; da Cruz, Mariana Murad

2016-12-01

Defecography is an established method of evaluating dynamic anorectal dysfunction, but conventional defecography does not allow for visualization of anatomic structures. The purpose of this study was to describe the use of dynamic 3-dimensional endovaginal ultrasonography for evaluating perineal descent in comparison with echodefecography (3-dimensional anorectal ultrasonography) and to study the relationship between perineal descent and symptoms and anatomic/functional abnormalities of the pelvic floor. This was a prospective study. The study was conducted at a large university tertiary care hospital. Consecutive female patients were eligible if they had pelvic floor dysfunction, obstructed defecation symptoms, and a score >6 on the Cleveland Clinic Florida Constipation Scale. Each patient underwent both echodefecography and dynamic 3-dimensional endovaginal ultrasonography to evaluate posterior pelvic floor dysfunction. Normal perineal descent was defined on echodefecography as puborectalis muscle displacement ≤2.5 cm; excessive perineal descent was defined as displacement >2.5 cm. Of 61 women, 29 (48%) had normal perineal descent; 32 (52%) had excessive perineal descent. Endovaginal ultrasonography identified 27 of the 29 patients in the normal group as having anorectal junction displacement ≤1 cm (mean = 0.6 cm; range, 0.1-1.0 cm) and a mean anorectal junction position of 0.6 cm (range, 0-2.3 cm) above the symphysis pubis during the Valsalva maneuver and correctly identified 30 of the 32 patients in the excessive perineal descent group. The κ statistic showed almost perfect agreement (κ = 0.86) between the 2 methods for categorization into the normal and excessive perineal descent groups. Perineal descent was not related to fecal or urinary incontinence or anatomic and functional factors (sphincter defects, pubovisceral muscle defects, levator hiatus area, grade II or III rectocele, intussusception, or anismus). The study did not include a control group without symptoms. Three-dimensional endovaginal ultrasonography is a reliable technique for assessment of perineal descent. Using this technique, excessive perineal descent can be defined as displacement of the anorectal junction >1 cm and/or its position below the symphysis pubis on Valsalva maneuver.

Clinical and manometric characteristics of patients with Parkinson's disease and esophageal symptoms.

PubMed

Su, A; Gandhy, R; Barlow, C; Triadafilopoulos, G

2017-04-01

Dysphagia is a common problem in patients with Parkinson's disease (PD); its etiology is multifactorial and its management is challenging. In this retrospective cohort analysis using prospectively collected data, we aimed to objectively characterize dysphagia and/or other esophageal symptoms in patients with PD, assess the prevalence of outflow obstruction as well as major or minor disorders of esophageal peristalsis leading to impaired esophageal clearance and highlight objective parameters that can help in the current management algorithm. Thirty-three consecutive patients with PD presenting with dysphagia, odynophagia, heartburn, regurgitation, chest pain, and weight loss underwent clinical and functional evaluation by high-resolution manometry (HRM). Esophagogastric junction (EGJ) outflow obstruction and major as well as minor disorders of peristalsis were then assessed using the Chicago classification (v3). Thirty-three PD patients with esophageal symptoms were enrolled in the study; 12 of them reported weight loss that was considered as potentially reflecting underlying esophageal dysfunction. The median age of the patients was 70 years (range: 53-89 years), 24 (75%) were men. The majority (62%) experienced dysphagia, likely contributing to weight loss in 41% of patients. Odynophagia was rare (6%) while GER symptoms, such as heartburn, regurgitation, and chest pain were noted in 37%, 31%, and 28% of patients, respectively. Using the hierarchy of the Chicago classification, 12 patients (39%) exhibited EGJ outflow obstruction, 16 (48%) diffuse esophageal spasm (DES), 18 (55%), ineffective esophageal peristalsis (IEM), 16 (48%) fragmented peristalsis, and only 2 patients (6%) had normal HRM tracings. There were no patients with HRM features of achalasia. Dysphagia is common in patients with PD and is associated with a high prevalence of underlying motility disturbances as identified by HRM. The exact impact of these motility abnormalities on symptom induction and their role in influencing clinical management are unclear and will require further study. © The Authors 2017. Published by Oxford University Press on behalf of International Society for Diseases of the Esophagus. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Upper esophageal sphincter abnormalities: frequent finding on high-resolution esophageal manometry and associated with poorer treatment response in achalasia.

PubMed

Chavez, Yamile H; Ciarleglio, Maria M; Clarke, John O; Nandwani, Monica; Stein, Ellen; Roland, Bani C

2015-01-01

Abnormalities of the upper esophageal sphincter (UES) on high-resolution esophageal manometry (HREM) have been observed in both symptomatic and asymptomatic individuals and are often interpreted as incidental findings of unclear clinical significance. Our primary aims were: (1) to assess the frequency of UES abnormalities in consecutive patients referred for HREM studies; and (2) to characterize the demographics, clinical symptoms, and manometric profiles associated with UES abnormalities as compared with those with normal UES function. We performed a retrospective study of 200 consecutive patients referred for HREM. Patients were divided into those with normal and abnormal UES function, including impaired relaxation (residual pressure >12 mm Hg), hypertensive (>104 mm Hg), and hypotensive (<34 mm Hg) resting pressure. Clinical and manometric profiles were compared. A total of 32.5% of patients had UES abnormalities, the majority of which were hypertensive (55.4%). Patients with achalasia were significantly more likely to have UES abnormalities as compared with normal UES function (57.2% vs. 42.9%, P=0.04), with the most frequent abnormality being a hypertensive UES (50%). In addition, patients with impaired lower esophageal sphincter (LES) relaxation (esophagogastric junction outflow obstruction or achalasia) were more likely to have an UES abnormality present as compared with those with normal LES relaxation (53.1% vs. 28.6%, P=0.01). When we assessed for treatment response among patients with achalasia, we found that subjects with evidence of UES dysfunction had significantly worse treatment outcomes as compared with those without UES abnormalities present (20% improved vs. 100%, P=0.015). This remained true even after adjusting for type of treatment received (surgical myotomy, per-oral endoscopic mytotomy, botulinum toxin injection, pneumatic dilatation, medical therapy, P=0.67) and achalasia subtype (P=1.00). UES abnormalities are a frequent finding on HREM studies, especially in patients with impaired LES relaxation, including both achalasia and esophagogastric junction outflow obstruction. Interestingly, the most common UES abnormality associated with achalasia was a hypertensive resting UES, despite the fact that achalasia is thought to spare striated muscle. Among patients with achalasia, we found a significant association between the lack of treatment response and the presence of UES dysfunction. The routine evaluation of UES function in patients referred for manometry may enhance our understanding of esophageal motility disorders and may yield important prognostic information, particularly in subjects with achalasia. Future prospective studies are needed to further delineate the underlying mechanism between UES dysfunction with achalasia and other esophageal motility disorders to predict treatment response and guide therapeutic treatment modalities.

Multi-level obstruction in obstructive sleep apnoea: prevalence, severity and predictive factors.

PubMed

Phua, C Q; Yeo, W X; Su, C; Mok, P K H

2017-11-01

To characterise multi-level obstruction in terms of prevalence, obstructive sleep apnoea severity and predictive factors, and to collect epidemiological data on upper airway morphology in obstructive sleep apnoea patients. Retrospective review of 250 obstructive sleep apnoea patients. On clinical examination, 171 patients (68.4 per cent) had multi-level obstruction, 49 (19.6 per cent) had single-level obstruction and 30 (12 per cent) showed no obstruction. Within each category of obstructive sleep apnoea severity, multi-level obstruction was more prevalent. Multi-level obstruction was associated with severe obstructive sleep apnoea (more than 30 events per hour) (p = 0.001). Obstructive sleep apnoea severity increased with the number of obstruction sites (correlation coefficient = 0.303, p < 0.001). Multi-level obstruction was more likely in younger (p = 0.042), male (p = 0.045) patients, with high body mass index (more than 30 kg/m2) (p < 0.001). Palatal (p = 0.004), tongue (p = 0.026) and lateral pharyngeal wall obstructions (p = 0.006) were associated with severe obstructive sleep apnoea. Multi-level obstruction is more prevalent in obstructive sleep apnoea and is associated with increased severity. Obstruction at certain anatomical levels contributes more towards obstructive sleep apnoea severity.

Do JJ Stents Increase the Effectiveness of Extracorporeal Shock Wave Lithotripsy for Pediatric Renal Stones?

PubMed

Gündüz, Metin; Sekmenli, Tamer; Ciftci, İlhan; Elmacı, Ahmet Midhat

2017-01-01

We aimed to evaluate the effects of preoperative urinary catheterization in nephrolithiasis treatment with extracorporeal shock wave lithotripsy (SWL). Patients admitted to the Department of Pediatric Surgery for renal stones between June 2012 and June 2014 were evaluated retrospectively. Patients were divided into 2 groups based on JJ stent placements. Group 1 did not receive JJ stents, while group 2 did. The recorded demographic data for each group included age, gender, stone size, location, sessions, and complications. The Elmed Complit ESWL system was used with 11-13 kV, and 1,000-1,200 shots in patients 2-4 years of age, and 11-14 kV, and 1,000-1,500 shots for patients over 4 years. In group 1, 18 sessions of SWL were performed on 8 female and 2 male children with a mean age of 4.5 (range 2-12) years and stone diameter of 9 (range 7-15) mm. The locations of the renal stones were in the upper pole in 1 patient, 7 in the lower pole, and 2 in the pelvis renalis. Postoperatively, 1 patient had hematuria, 2 had dysuria, and one had a stone in the external urethral meatus. Eighty percent of patients were stone free; there were no fragmentations in 2 patients, and 1 patient discontinued treatment. In group 2, 15 SWL sessions were performed on 5 female and 5 male children aged 4 (range 3-5) and the stone diameter was 9 (range 7-16) mm. The locations of the renal stones were in the upper pole in 6 patients, in the lower pole in 3 patients, and in the ureteropelvic junction in one patient. JJ stents were placed in all patients preoperatively. Postoperatively, 3 patients had hematuria and one had dysuria. At the end of the study, all of the patients were stone free. Statistically, there were no differences in age, gender, stone size, location, and the number of sessions. Our results indicate that SWL without preoperative ureteral stenting is an effective and safe procedure that can be carried out in the pediatric population. Preoperative JJ stenting is unnecessary in patients, especially in those with smaller stone diameters. © 2016 S. Karger AG, Basel.

Arsenic Compromises Conducting Airway Epithelial Barrier Properties in Primary Mouse and Immortalized Human Cell Cultures

PubMed Central

Sherwood, Cara L.; Liguori, Andrew E.; Olsen, Colin E.; Lantz, R. Clark; Burgess, Jefferey L.; Boitano, Scott

2013-01-01

Arsenic is a lung toxicant that can lead to respiratory illness through inhalation and ingestion, although the most common exposure is through contaminated drinking water. Lung effects reported from arsenic exposure include lung cancer and obstructive lung disease, as well as reductions in lung function and immune response. As part of their role in innate immune function, airway epithelial cells provide a barrier that protects underlying tissue from inhaled particulates, pathogens, and toxicants frequently found in inspired air. We evaluated the effects of a five-day exposure to environmentally relevant levels of arsenic {<4μM [~300 μg/L (ppb)] as NaAsO2} on airway epithelial barrier function and structure. In a primary mouse tracheal epithelial (MTE) cell model we found that both micromolar (3.9 μM) and submicromolar (0.8 μM) arsenic concentrations reduced transepithelial resistance, a measure of barrier function. Immunofluorescent staining of arsenic-treated MTE cells showed altered patterns of localization of the transmembrane tight junction proteins claudin (Cl) Cl-1, Cl-4, Cl-7 and occludin at cell-cell contacts when compared with untreated controls. To better quantify arsenic-induced changes in tight junction transmembrane proteins we conducted arsenic exposure experiments with an immortalized human bronchial epithelial cell line (16HBE14o-). We found that arsenic exposure significantly increased the protein expression of Cl-4 and occludin as well as the mRNA levels of Cl-4 and Cl-7 in these cells. Additionally, arsenic exposure resulted in altered phosphorylation of occludin. In summary, exposure to environmentally relevant levels of arsenic can alter both the function and structure of airway epithelial barrier constituents. These changes likely contribute to the observed arsenic-induced loss in basic innate immune defense and increased infection in the airway. PMID:24349408

Rhinovirus disrupts the barrier function of polarized airway epithelial cells.

PubMed

Sajjan, Umadevi; Wang, Qiong; Zhao, Ying; Gruenert, Dieter C; Hershenson, Marc B

2008-12-15

Secondary bacterial infection following rhinovirus (RV) infection has been recognized in chronic obstructive pulmonary disease. We sought to understand mechanisms by which RV infection facilitates secondary bacterial infection. Primary human airway epithelial cells grown at air-liquid interface and human bronchial epithelial (16HBE14o-) cells grown as polarized monolayers were infected apically with RV. Transmigration of bacteria (nontypeable Haemophilus influenzae and others) was assessed by colony counting and transmission electron microscopy. Transepithelial resistance (R(T)) was measured by using a voltmeter. The distribution of zona occludins (ZO)-1 was determined by immunohistochemistry and immunoblotting. Epithelial cells infected with RV showed 2-log more bound bacteria than sham-infected cultures, and bacteria were recovered from the basolateral media of RV- but not sham-infected cells. Infection of polarized airway epithelial cell cultures with RV for 24 hours caused a significant decrease in R(T) without causing cell death or apoptosis. Ultraviolet-treated RV did not decrease R(T), suggesting a requirement for viral replication. Reduced R(T) was associated with increased paracellular permeability, as determined by flux of fluorescein isothiocyanate (FITC)-inulin. Neutralizing antibodies to tumor necrosis factor (TNF)-alpha, IFN-gamma and IL-1beta reversed corresponding cytokine-induced reductions in R(T) but not that induced by RV, indicating that the RV effect is independent of these proinflammatory cytokines. Confocal microscopy and immunoblotting revealed the loss of ZO-1 from tight junction complexes in RV-infected cells. Intranasal inoculation of mice with RV1B also caused the loss of ZO-1 from the bronchial epithelium tight junctions in vivo. RV facilitates binding, translocation, and persistence of bacteria by disrupting airway epithelial barrier function.

Unique features of esophagogastric junction pressure topography in hiatus hernia patients with dysphagia.

PubMed

Pandolfino, John E; Kwiatek, Monika A; Ho, Kim; Scherer, John R; Kahrilas, Peter J

2010-01-01

Our aim was to assess pressure dynamics within the esophagogastric junction (EGJ) in sliding hiatus hernia (HH) during normal peristalsis and to compare the pressure profiles of HH patients with gastroesophageal reflux disease (GERD) symptoms (HH-GERD) to HH patients with dysphagia (HH-dysphagia). High-resolution manometry studies in 230 consecutive patients and 68 controls were reviewed. HH patients were defined by a >or=1.5 cm separation between the lower esophageal sphincter (LES) and crural diaphragm (CD) on pressure topography plots. The HH population was further culled to eliminate those patients with motor disorders or stricture. The study groups were composed of 18 HH patients with only reflux symptoms and 10 HH patients with only dysphagia. Analysis of the pressure dynamics within the EGJ was performed at rest and after swallowing to independently quantify the LES and CD contributions to residual EGJ pressure, as well as the magnitude and genesis of distal esophageal intrabolus pressure (IBP). Differences among study groups were analyzed with analysis of variance. After swallows, HH-dysphagia patients had greater residual CD pressure (9 mmHg; standard deviation [SD], 4) and IBP pressure (19 mmHg; SD, 4) compared to HH-GERD patients (5 mmHg; SD, 2; and 12 mmHg; SD, 2, respectively; P<.001) or normal subjects (NA; 11 mmHg; SD, 3; P<.001). Sliding HH alters the pressure dynamics through the EGJ and can lead to a functional obstruction. Patients with HH and dysphagia have greater pressures through the CD compared to HH patients with GERD symptoms, supporting the hypothesis that sliding HH in and of itself may be responsible for dysphagia. Copyright (c) 2010 Mosby, Inc. All rights reserved.

Hydronephrosis with ureteritis developed in C57BL/6N mice carrying the congenic region derived from MRL/MpJ-type chromosome 11.

PubMed

Ichii, Osamu; Chihara, Masataka; Lee, Shin-Hyo; Nakamura, Teppei; Otsuka-Kanazawa, Saori; Horino, Taro; Elewa, Yaser Hosny Ali; Kon, Yasuhiro

2017-03-01

Inbred MRL/MpJ mice show several unique phenotypes in tissue regeneration processes and the urogenital and immune systems. Clarifying the genetic and molecular bases of these phenotypes requires the analysis of their genetic susceptibility locus. Herein, hydronephrosis development was incidentally observed in MRL/MpJ-derived chromosome 11 (D11Mit21-212)-carrying C57BL/6N-based congenic mice, which developed bilateral or unilateral hydronephrosis in both males and females with 23.5% and 12.5% prevalence, respectively. Histopathologically, papillary malformations of the transitional epithelium in the pelvic-ureteric junction seemed to constrict the ureter luminal entrance. Characteristically, eosinophilic crystals were observed in the lumen of diseased ureters. These ureters were surrounded by infiltrating cells mainly composed of numerous CD3 +  T-cells and B220 +  B-cells. Furthermore, several Iba-1 +  macrophages, Gr-1 +  granulocytes, mast cells and chitinase 3-like 3/Ym1 (an important inflammatory lectin)-positive cells were detected. Eosinophils also accumulated to these lesions in diseased ureters. Some B6.MRL-(D11Mit21-D11Mit212) mice had duplicated ureters. We determined >100 single nucleotide variants between C57BL/6N- and MRL/MpJ-type chromosome 11 congenic regions, which were associated with nonsynonymous substitution, frameshift or stopgain of coding proteins. In conclusion, B6.MRL-(D11Mit21-D11Mit212) mice spontaneously developed hydronephrosis due to obstructive uropathy with inflammation. Thus, this mouse line would be useful for molecular pathological analysis of obstructive uropathy in experimental medicine.

Analysis of obstruction site in obstructive sleep apnea syndrome patients by drug induced sleep endoscopy.

PubMed

Koo, Soo Kweon; Choi, Jang Won; Myung, Nam Suk; Lee, Hyoung Ju; Kim, Yang Jae; Kim, Young Joong

2013-01-01

We analyzed site, pattern and degree of obstruction in Korean male obstructive sleep apnea syndrome (OSAS) patients by drug-induced sleep endoscopy (DISE). We also investigated possible links between BMI, AHI and DISE findings. Sixty-nine male patients underwent DISE. DISE findings were reported using our classification system in which modified 'VOTE classification' - obstruction type, site of obstruction, degree of obstruction and anatomical site contributing obstruction - was reported. Associations were analyzed among the results of the polysomnography, patients' characteristics and DISE finding. Multilevel airway obstruction was found in 84.06% of patients and 15.94% had a unilevel obstruction. Among those with unilevel obstruction, 90.90% had retropalatal level obstruction and 9.10% had retrolingual level obstruction. Palate with lateral pharyngeal wall obstruction (49.28%) is the most common obstruction type of the retropalatal level and tongue with lateral pharyngeal wall (37.68%) is the most common obstruction type of the retrolingual level. Examining the relation between obstruction site according to body mass index (BMI) and severity of OSAS (apnea hypopnea index, AHI), the lateral pharyngeal wall had an increasing tendency associated with higher BMI and higher AHI. But the lateral pharyngeal wall of both levels was statistically significant associated with higher AHI. The majority of the Korean male OSAS patients have multilevel obstruction and according to BMI and AHI, the DISE findings indicate that the lateral pharyngeal wall is the most important anatomical site contributing to obstruction regardless of the level at which the obstruction lies. © 2013 Elsevier Inc. All rights reserved.

Achondroplasia: Current Options and Future Perspective.

PubMed

Bouali, Houda; Latrech, Hanane

2015-06-01

Achondroplasia is a human bone genetic disorder of the growth plate and is the most common form of inherited disproportionate short stature. It is inherited as an autosomal dominant disease with essentially complete penetrance. Of these most have the same point mutation in the gene for fibroblast growth factor receptor 3 (FGFR3) which is a negative regulator of bone growth. The clinical and radiological features of achondroplasia can easily be identified; they include disproportionate short stature with rhizomelic shortening, macrocephaly with frontal bossing, midface hypoplasia, lumbar hyperlordosis, and a trident hand configuration. The majority of achondroplasts have a normal intelligence, but many social and medical complications may compromise a full and productive life. Some of them have serious health consequences related to hydrocephalus, craniocervical junction compression, or upper-airway obstruction. In this article, we discuss a number of treatments from the surgical limb lengthening approach and the Recombinant Growth Hormone (rhGH) treatment, to future treatments, which include the Natriuretic Peptide C-type (CNP). The discussion is a comparative study of the complications and drawbacks of various experiments using numerous strategies.

Current Therapeutic Options for Esophageal Motor Disorders as Defined by the Chicago Classification.

PubMed

Zerbib, Frank; Roman, Sabine

2015-07-01

With the development of high-resolution manometry and specific metrics to characterize esophageal motility, the Chicago Classification has become the gold standard for the diagnosis of esophageal motor disorders. Major and significant disorders, that is, never observed in healthy subjects, are achalasia, esophagogastric junction outflow obstruction, distal esophageal spasm, absent peristalsis, and hypercontractile (Jackhammer) esophagus. Achalasia subtyping is relevant to predict the response to endoscopic and surgical therapies as several studies suggest that, pneumatic dilation is less effective than Heller myotomy, in type III achalasia. Peroral endoscopic myotomy, initially developed in expert centers, is a promising technique for the treatment of achalasia. The medical therapeutic options for distal esophageal spasm and hypercontractile esophagus are smooth muscle relaxants and pain modulators. Intraesophageal injection of botulinum toxin might be an interesting option for treatment of these disorders but further studies are required to determine the optimal injection protocol and the best candidates based on manometric patterns. The treatment of hypotensive motility disorders is disappointing and relies mainly on dietary and lifestyle changes as no effective esophageal prokinetic is currently available.

The importance of patient-reported outcome measures in reconstructive urology.

PubMed

Jackson, Matthew J; N'Dow, James; Pickard, Rob

2010-11-01

Patient-reported outcome measures (PROMs) are now recognised as the most appropriate instruments to assess the effectiveness of healthcare interventions from the patient's perspective. The purpose of this review was to identify recent publications describing the use of PROMs following reconstructive urological surgery. A wide systematic search identified only three original articles published in the last 2 years that prospectively assessed effectiveness using a patient-completed condition-specific or generic health-related quality of life (HRQoL) instrument. These publications illustrate the need to administer PROMs at a postoperative interval relevant to the anticipated recovery phase of individual procedures. They also highlight the difference in responsiveness of generic HRQoL instruments to symptomatic improvement between straightforward conditions such as pelviureteric junction obstruction and complex multidimensional conditions such as meningomyelocele. PROMs uptake and awareness is increasing in reconstructive urology but more work is required to demonstrate the effectiveness of surgical procedures for patients and healthcare funders alike. Healthcare policy-makers now rely on these measures to determine whether specific treatments are worth financing and to compare outcomes between institutions.

Uniportal thoracoscopy combined with laparoscopy as minimally invasive treatment of esophageal cancer

PubMed Central

Caronia, Francesco Paolo; Arrigo, Ettore; Failla, Andrea Valentino; Sgalambro, Francesco; Giannone, Giorgio; Lo Monte, Attilio Ignazio; Cajozzo, Massimo; Santini, Mario

2018-01-01

A 67-year-old man was referred to our attention for management of esophageal adenocarcinoma, localized at the level of the esophagogastric junction and obstructed the 1/3 of the esophageal lumen. Due to the extension of the disease (T3N1M0-Stage IIIA), the patient underwent neo-adjuvant chemo-radiation therapy and he was then scheduled for a minimally invasive surgical procedure including laparoscopic gastroplasty, uniportal thoracoscopic esophageal dissection and intrathoracic end-to-end esophago-gastric anastomosis. No intraoperative and post-operative complications were seen. The patient was discharged in post-operative day 9. Pathological study confirmed the diagnosis of adenocarcinoma (T2N1M0-Stage IIB) and he underwent adjuvant chemotherapy. At the time of present paper, patient is alive and well without signs of recurrence or metastasis. Our minimally approach compared to standard open procedure would help reduce post-operative pain and favours early return to normal activity. However, future experiences with a control group are required before our strategy can be widely used. PMID:29850166

Uniportal thoracoscopy combined with laparoscopy as minimally invasive treatment of esophageal cancer.

PubMed

Caronia, Francesco Paolo; Arrigo, Ettore; Failla, Andrea Valentino; Sgalambro, Francesco; Giannone, Giorgio; Lo Monte, Attilio Ignazio; Cajozzo, Massimo; Santini, Mario; Fiorelli, Alfonso

2018-04-01

A 67-year-old man was referred to our attention for management of esophageal adenocarcinoma, localized at the level of the esophagogastric junction and obstructed the 1/3 of the esophageal lumen. Due to the extension of the disease (T3N1M0-Stage IIIA), the patient underwent neo-adjuvant chemo-radiation therapy and he was then scheduled for a minimally invasive surgical procedure including laparoscopic gastroplasty, uniportal thoracoscopic esophageal dissection and intrathoracic end-to-end esophago-gastric anastomosis. No intraoperative and post-operative complications were seen. The patient was discharged in post-operative day 9. Pathological study confirmed the diagnosis of adenocarcinoma (T2N1M0-Stage IIB) and he underwent adjuvant chemotherapy. At the time of present paper, patient is alive and well without signs of recurrence or metastasis. Our minimally approach compared to standard open procedure would help reduce post-operative pain and favours early return to normal activity. However, future experiences with a control group are required before our strategy can be widely used.

Three-junction solar cell

DOEpatents

Ludowise, Michael J.

1986-01-01

A photovoltaic solar cell is formed in a monolithic semiconductor. The cell contains three junctions. In sequence from the light-entering face, the junctions have a high, a medium, and a low energy gap. The lower junctions are connected in series by one or more metallic members connecting the top of the lower junction through apertures to the bottom of the middle junction. The upper junction is connected in voltage opposition to the lower and middle junctions by second metallic electrodes deposited in holes 60 through the upper junction. The second electrodes are connected to an external terminal.

Supramolecular Systems and Chemical Reactions in Single-Molecule Break Junctions.

PubMed

Li, Xiaohui; Hu, Duan; Tan, Zhibing; Bai, Jie; Xiao, Zongyuan; Yang, Yang; Shi, Jia; Hong, Wenjing

2017-04-01

The major challenges of molecular electronics are the understanding and manipulation of the electron transport through the single-molecule junction. With the single-molecule break junction techniques, including scanning tunneling microscope break junction technique and mechanically controllable break junction technique, the charge transport through various single-molecule and supramolecular junctions has been studied during the dynamic fabrication and continuous characterization of molecular junctions. This review starts from the charge transport characterization of supramolecular junctions through a variety of noncovalent interactions, such as hydrogen bond, π-π interaction, and electrostatic force. We further review the recent progress in constructing highly conductive molecular junctions via chemical reactions, the response of molecular junctions to external stimuli, as well as the application of break junction techniques in controlling and monitoring chemical reactions in situ. We suggest that beyond the measurement of single molecular conductance, the single-molecule break junction techniques provide a promising access to study molecular assembly and chemical reactions at the single-molecule scale.

Monolithic multi-color light emission/detection device

DOEpatents

Wanlass, Mark W.

1995-01-01

A single-crystal, monolithic, tandem, multi-color optical transceiver device is described, including (a) an InP substrate having upper and lower surfaces, (b) a first junction on the upper surface of the InP substrate, (c) a second junction on the first junction. The first junction is preferably GaInAsP of defined composition, and the second junction is preferably InP. The two junctions are lattice matched. The second junction has a larger energy band gap than the first junction. Additional junctions having successively larger energy band gaps may be included. The device is capable of simultaneous and distinct multi-color emission and detection over a single optical fiber.

Electronic thermometry in tunable tunnel junction

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

Maksymovych, Petro

A tunable tunnel junction thermometry circuit includes a variable width tunnel junction between a test object and a probe. The junction width is varied and a change in thermovoltage across the junction with respect to the change in distance across the junction is determined. Also, a change in biased current with respect to a change in distance across the junction is determined. A temperature gradient across the junction is determined based on a mathematical relationship between the temperature gradient, the change in thermovoltage with respect to distance and the change in biased current with respect to distance. Thermovoltage may bemore » measured by nullifying a thermoelectric tunneling current with an applied voltage supply level. A piezoelectric actuator may modulate the probe, and thus the junction width, to vary thermovoltage and biased current across the junction. Lock-in amplifiers measure the derivatives of the thermovoltage and biased current modulated by varying junction width.« less

Spectral analysis of bowel sounds in intestinal obstruction using an electronic stethoscope.

PubMed

Ching, Siok Siong; Tan, Yih Kai

2012-09-07

To determine the value of bowel sounds analysis using an electronic stethoscope to support a clinical diagnosis of intestinal obstruction. Subjects were patients who presented with a diagnosis of possible intestinal obstruction based on symptoms, signs, and radiological findings. A 3M™ Littmann(®) Model 4100 electronic stethoscope was used in this study. With the patients lying supine, six 8-second recordings of bowel sounds were taken from each patient from the lower abdomen. The recordings were analysed for sound duration, sound-to-sound interval, dominant frequency, and peak frequency. Clinical and radiological data were reviewed and the patients were classified as having either acute, subacute, or no bowel obstruction. Comparison of bowel sound characteristics was made between these subgroups of patients. In the presence of an obstruction, the site of obstruction was identified and bowel calibre was also measured to correlate with bowel sounds. A total of 71 patients were studied during the period July 2009 to January 2011. Forty patients had acute bowel obstruction (27 small bowel obstruction and 13 large bowel obstruction), 11 had subacute bowel obstruction (eight in the small bowel and three in large bowel) and 20 had no bowel obstruction (diagnoses of other conditions were made). Twenty-five patients received surgical intervention (35.2%) during the same admission for acute abdominal conditions. A total of 426 recordings were made and 420 recordings were used for analysis. There was no significant difference in sound-to-sound interval, dominant frequency, and peak frequency among patients with acute bowel obstruction, subacute bowel obstruction, and no bowel obstruction. In acute large bowel obstruction, the sound duration was significantly longer (median 0.81 s vs 0.55 s, P = 0.021) and the dominant frequency was significantly higher (median 440 Hz vs 288 Hz, P = 0.003) when compared to acute small bowel obstruction. No significant difference was seen between acute large bowel obstruction and large bowel pseudo-obstruction. For patients with small bowel obstruction, the sound-to-sound interval was significantly longer in those who subsequently underwent surgery compared with those treated non-operatively (median 1.29 s vs 0.63 s, P < 0.001). There was no correlation between bowel calibre and bowel sound characteristics in both acute small bowel obstruction and acute large bowel obstruction. Auscultation of bowel sounds is non-specific for diagnosing bowel obstruction. Differences in sound characteristics between large bowel and small bowel obstruction may help determine the likely site of obstruction.

Spectral analysis of bowel sounds in intestinal obstruction using an electronic stethoscope

PubMed Central

Ching, Siok Siong; Tan, Yih Kai

2012-01-01

AIM: To determine the value of bowel sounds analysis using an electronic stethoscope to support a clinical diagnosis of intestinal obstruction. METHODS: Subjects were patients who presented with a diagnosis of possible intestinal obstruction based on symptoms, signs, and radiological findings. A 3M™ Littmann® Model 4100 electronic stethoscope was used in this study. With the patients lying supine, six 8-second recordings of bowel sounds were taken from each patient from the lower abdomen. The recordings were analysed for sound duration, sound-to-sound interval, dominant frequency, and peak frequency. Clinical and radiological data were reviewed and the patients were classified as having either acute, subacute, or no bowel obstruction. Comparison of bowel sound characteristics was made between these subgroups of patients. In the presence of an obstruction, the site of obstruction was identified and bowel calibre was also measured to correlate with bowel sounds. RESULTS: A total of 71 patients were studied during the period July 2009 to January 2011. Forty patients had acute bowel obstruction (27 small bowel obstruction and 13 large bowel obstruction), 11 had subacute bowel obstruction (eight in the small bowel and three in large bowel) and 20 had no bowel obstruction (diagnoses of other conditions were made). Twenty-five patients received surgical intervention (35.2%) during the same admission for acute abdominal conditions. A total of 426 recordings were made and 420 recordings were used for analysis. There was no significant difference in sound-to-sound interval, dominant frequency, and peak frequency among patients with acute bowel obstruction, subacute bowel obstruction, and no bowel obstruction. In acute large bowel obstruction, the sound duration was significantly longer (median 0.81 s vs 0.55 s, P = 0.021) and the dominant frequency was significantly higher (median 440 Hz vs 288 Hz, P = 0.003) when compared to acute small bowel obstruction. No significant difference was seen between acute large bowel obstruction and large bowel pseudo-obstruction. For patients with small bowel obstruction, the sound-to-sound interval was significantly longer in those who subsequently underwent surgery compared with those treated non-operatively (median 1.29 s vs 0.63 s, P < 0.001). There was no correlation between bowel calibre and bowel sound characteristics in both acute small bowel obstruction and acute large bowel obstruction. CONCLUSION: Auscultation of bowel sounds is non-specific for diagnosing bowel obstruction. Differences in sound characteristics between large bowel and small bowel obstruction may help determine the likely site of obstruction. PMID:22969233

A Computational Study of the Respiratory Airflow Characteristics in Normal and Obstructed Human Airways

DTIC Science & Technology

2014-01-01

normal and three different obstructed airway geometries, consisting of symmetric, asym- metric, and random obstructions. Fig. 2 shows the geometric ...normal and obstructed airways Airway resistance is a measure of the opposition to the airflow caused by geometric properties, such as airway obstruction...pressure drops. Resistance values were dependent on the degree and geometric distribution of the obstruction sites. In the symmetric obstruction model

Gap junctions contain different amounts of cholesterol which undergo unique sequestering processes during fiber cell differentiation in the embryonic chicken lens.

PubMed

Biswas, Sondip K; Lo, Woo-Kuen

2007-03-09

To determine the possible changes in the distribution of cholesterol in gap junction plaques during fiber cell differentiation and maturation in the embryonic chicken lens. The possible mechanism by which cholesterol is removed from gap junction plaques is also investigated. Filipin cytochemistry in conjunction with freeze-fracture TEM was used to visualize cholesterol, as represented by filipin-cholesterol complexes (FCCs) in gap junction plaques. Quantitative analysis on the heterogeneous distribution of cholesterol in gap junction plaques was conducted from outer and inner cortical regions. A novel technique combining filipin cytochemistry with freeze-fracture replica immunogold labeling (FRIL) was used to label Cx45.6 and Cx56 antibodies in cholesterol-containing gap junctions. Filipin cytochemistry and freeze-fracture TEM and thin-section TEM were used to examine the appearance and nature of the cholesterol-containing vesicular structures associated with gap junction plaques. Chicken lens fibers contain cholesterol-rich, cholesterol-intermediate and cholesterol-free gap junction populations in both outer and inner cortical regions. Filipin cytochemistry and FRIL studies confirmed that cholesterol-containing junctions were gap junctions. Quantitative analysis showed that approximately 86% of gap junctions in the outer cortical zone were cholesterol-rich gap junctions, whereas approximately 81% of gap junctions in the inner cortical zone were cholesterol-free gap junctions. A number of pleiomorphic cholesterol-rich vesicles of varying sizes were often observed in the gap junction plaques. They appear to be involved in the removal of cholesterol from gap junction plaques through endocytosis. Gap junctions in the young fibers are enriched with cholesterol because they are assembled in the unique cholesterol-rich cell membranes in the lens. A majority of cholesterol-rich gap junctions in the outer young fibers are transformed into cholesterol-free ones in the inner mature fibers during fiber cell maturation. A distinct endocytotic process appears to be involved in removing cholesterol from the cholesterol-containing gap junctions, and it may play a major role in the transformation of cholesterol-rich gap junctions into cholesterol-free ones during fiber cell maturation.

Monolithic multi-color light emission/detection device

DOEpatents

Wanlass, M.W.

1995-02-21

A single-crystal, monolithic, tandem, multi-color optical transceiver device is described, including (a) an InP substrate having upper and lower surfaces, (b) a first junction on the upper surface of the InP substrate, (c) a second junction on the first junction. The first junction is preferably GaInAsP of defined composition, and the second junction is preferably InP. The two junctions are lattice matched. The second junction has a larger energy band gap than the first junction. Additional junctions having successively larger energy band gaps may be included. The device is capable of simultaneous and distinct multi-color emission and detection over a single optical fiber. 5 figs.

Chronic obstructive pulmonary disease: knowing what we mean, meaning what we say.

PubMed

Joshi, J M

2008-01-01

Chronic obstructive pulmonary disease (COPD) is defined in several different ways using different criteria based on symptoms, physiological impairment and pathological abnormalities. While some use COPD to mean smoking related chronic airway disease, others include all disorders causing chronic airway obstruction. When COPD is used as a broad descriptive term, specific disorders that cause chronic airway obstruction remain under-diagnosed and the prevalence estimates vary considerably. The lack of agreement over the precise terminology and classification of COPD has resulted in widespread confusion. Terminology includes definition, diagnostic criteria, and a system for staging severity. Recently, COPD is defined more clearly and diagnosed using precise criteria that include tobacco smoking greater than 10 pack years, symptoms and airway obstruction on spirometry. A multi-dimensional severity grading system, the BODE (body mass index, obstruction, dyspnoea, and exercise tolerance) index has been designed to assess the respiratory and systemic expressions of COPD. This review proposes that the broad group of chronic disorders of the airways (with or without airway obstruction) be called chronic airway disease (CAD). The term COPD should be used exclusively for tobacco smoking related chronic airway disease. Chronic airway obstruction or obstructive lung disease may be used to define those conditions with airways obstruction caused by factors other than tobacco smoking. The aetiology may be appended to the label, for example, chronic airway obstruction/obstructive lung disease associated with bronchiectasis, chronic airway obstruction/obstructive lung disease associated with obliterative bronchiolitis or chronic airway obstruction/obstructive lung disease due to biomass fuel/occupational exposure.

Gap/silicon Tandem Solar Cell with Extended Temperature Range

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A. (Inventor)

2006-01-01

A two-junction solar cell has a bottom solar cell junction of crystalline silicon, and a top solar cell junction of gallium phosphide. A three (or more) junction solar cell has bottom solar cell junctions of silicon, and a top solar cell junction of gallium phosphide. The resulting solar cells exhibit improved extended temperature operation.

Gap and tight junctions in the formation of feather branches: A descriptive ultrastructural study.

PubMed

Alibardi, Lorenzo

2010-08-20

The present study has focused on the distribution and ultrastructure of gap and tight junctions responsible for the formation of the barb/barbule branching in developing feathers using immunocytochemical detection. Apart from desmosomes, both tight and gap junctions are present between differentiating barb/barbule cells and during keratinization. While gap junctions are rare along the perimeter of these cells, tight junctions tend to remain localized in nodes joining barbule cells and between barb cells of the ramus. Occludin and connexin-26 but not connexin-43 have been detected between barb medullary, barb cortical and barbule cells during formation of barbs. Gap junctions are present in supportive cells located in the vicinity of barbule cells and destined to degenerate, but no close junctions are present between supportive and barb/barbule cells. Close junctions mature into penta-laminar junctions that are present between mature barb/barbule cells. Immunolabeling for occludin and Cx26 is rare along these cornified junctions. The junctions allow barb/barbule cells to remain connected until feather-keratin form the mature corneous syncytium that constitutes the barbs. A discussion of the role of gap and tight junctions during feather morphogenesis is presented. 2010 Elsevier GmbH. All rights reserved.

An EMMPRIN-γ-catenin-Nm23 complex drives ATP production and actomyosin contractility at endothelial junctions.

PubMed

Moreno, Vanessa; Gonzalo, Pilar; Gómez-Escudero, Jesús; Pollán, Ángela; Acín-Pérez, Rebeca; Breckenridge, Mark; Yáñez-Mó, María; Barreiro, Olga; Orsenigo, Fabrizio; Kadomatsu, Kenji; Chen, Christopher S; Enríquez, José A; Dejana, Elisabetta; Sánchez-Madrid, Francisco; Arroyo, Alicia G

2014-09-01

Cell-cell adhesions are important sites through which cells experience and resist forces. In endothelial cells, these forces regulate junction dynamics and determine endothelial barrier strength. We identify the Ig superfamily member EMMPRIN (also known as basigin) as a coordinator of forces at endothelial junctions. EMMPRIN localization at junctions correlates with endothelial junction strength in different mouse vascular beds. Accordingly, EMMPRIN-deficient mice show altered junctions and increased junction permeability. Lack of EMMPRIN alters the localization and function of VE-cadherin (also known as cadherin-5) by decreasing both actomyosin contractility and tugging forces at endothelial cell junctions. EMMPRIN ensures proper actomyosin-driven maturation of competent endothelial junctions by forming a molecular complex with γ-catenin (also known as junction plakoglobin) and Nm23 (also known as NME1), a nucleoside diphosphate kinase, thereby locally providing ATP to fuel the actomyosin machinery. These results provide a novel mechanism for the regulation of actomyosin contractility at endothelial junctions and might have broader implications in biological contexts such as angiogenesis, collective migration and tissue morphogenesis by coupling compartmentalized energy production to junction assembly. © 2014. Published by The Company of Biologists Ltd.

An EMMPRIN–γ-catenin–Nm23 complex drives ATP production and actomyosin contractility at endothelial junctions

PubMed Central

Moreno, Vanessa; Gonzalo, Pilar; Gómez-Escudero, Jesús; Pollán, Ángela; Acín-Pérez, Rebeca; Breckenridge, Mark; Yáñez-Mó, María; Barreiro, Olga; Orsenigo, Fabrizio; Kadomatsu, Kenji; Chen, Christopher S.; Enríquez, José A.; Dejana, Elisabetta; Sánchez-Madrid, Francisco; Arroyo, Alicia G.

2014-01-01

ABSTRACT Cell–cell adhesions are important sites through which cells experience and resist forces. In endothelial cells, these forces regulate junction dynamics and determine endothelial barrier strength. We identify the Ig superfamily member EMMPRIN (also known as basigin) as a coordinator of forces at endothelial junctions. EMMPRIN localization at junctions correlates with endothelial junction strength in different mouse vascular beds. Accordingly, EMMPRIN-deficient mice show altered junctions and increased junction permeability. Lack of EMMPRIN alters the localization and function of VE-cadherin (also known as cadherin-5) by decreasing both actomyosin contractility and tugging forces at endothelial cell junctions. EMMPRIN ensures proper actomyosin-driven maturation of competent endothelial junctions by forming a molecular complex with γ-catenin (also known as junction plakoglobin) and Nm23 (also known as NME1), a nucleoside diphosphate kinase, thereby locally providing ATP to fuel the actomyosin machinery. These results provide a novel mechanism for the regulation of actomyosin contractility at endothelial junctions and might have broader implications in biological contexts such as angiogenesis, collective migration and tissue morphogenesis by coupling compartmentalized energy production to junction assembly. PMID:24994937

Abundance and ultrastructural diversity of neuronal gap junctions in the OFF and ON sublaminae of the inner plexiform layer of rat and mouse retina.

PubMed

Kamasawa, N; Furman, C S; Davidson, K G V; Sampson, J A; Magnie, A R; Gebhardt, B R; Kamasawa, M; Yasumura, T; Zumbrunnen, J R; Pickard, G E; Nagy, J I; Rash, J E

2006-11-03

Neuronal gap junctions are abundant in both outer and inner plexiform layers of the mammalian retina. In the inner plexiform layer (IPL), ultrastructurally-identified gap junctions were reported primarily in the functionally-defined and anatomically-distinct ON sublamina, with few reported in the OFF sublamina. We used freeze-fracture replica immunogold labeling and confocal microscopy to quantitatively analyze the morphologies and distributions of neuronal gap junctions in the IPL of adult rat and mouse retina. Under "baseline" conditions (photopic illumination/general anesthesia), 649 neuronal gap junctions immunogold-labeled for connexin36 were identified in rat IPL, of which 375 were photomapped to OFF vs. ON sublaminae. In contrast to previous reports, the volume-density of gap junctions was equally abundant in both sublaminae. Five distinctive morphologies of gap junctions were identified: conventional crystalline and non-crystalline "plaques" (71% and 3%), plus unusual "string" (14%), "ribbon" (7%) and "reticular" (2%) forms. Plaque and reticular gap junctions were distributed throughout the IPL. However, string and ribbon gap junctions were restricted to the OFF sublamina, where they represented 48% of gap junctions in that layer. In string and ribbon junctions, curvilinear strands of connexons were dispersed over 5 to 20 times the area of conventional plaques having equal numbers of connexons. To define morphologies of gap junctions under different light-adaptation conditions, we examined an additional 1150 gap junctions from rats and mice prepared after 30 min of photopic, mesopic and scotopic illumination, with and without general anesthesia. Under these conditions, string and ribbon gap junctions remained abundant in the OFF sublamina and absent in the ON sublamina. Abundant gap junctions in the OFF sublamina of these two rodents with rod-dominant retinas revealed previously-undescribed but extensive pathways for inter-neuronal communication; and the wide dispersion of connexons in string and ribbon gap junctions suggests unique structural features of gap junctional coupling in the OFF vs. ON sublamina.

Clinical presentation and outcome of cats with circumcaval ureters associated with a ureteral obstruction.

PubMed

Steinhaus, J; Berent, A C; Weisse, C; Eatroff, A; Donovan, T; Haddad, J; Bagley, D

2015-01-01

Circumcaval ureters (CU) are a rare embryological malformation resulting in ventral displacement of the caudal vena cava, which crosses the ureter, potentially causing a ureteral stricture. To evaluate cats with obstructed CU(s) and report the presenting signs, diagnostics, treatment(s), and outcomes. Cats with obstructed CU(s) were compared to ureterally obstructed cats without CU(s). 193 cats; 22 circumcaval obstructed (Group 1); 106 non-circumcaval obstructed (Group 2); 65 non-obstructed necropsy cases (Group 3). Retrospective study, review of medical records for cats treated for benign ureteral obstructions from AMC and University of Pennsylvania between 2009 and 2013. surgical treatment of benign ureteral obstruction, complete medical record including radiographic, ultrasonographic, biochemistry, and surgical findings. Seventeen percent (22/128) of obstructed cats had a CU (80% right-sided) compared to 14% (9/65) non-obstructed necropsy cats (89% right-sided). Clinical presentation, radiographic findings, and creatinine were not statistically different between Groups 1 and 2. Strictures were a statistically more common (40%) cause of ureteral obstruction in Group 1 compared to Group 2 (17%) (P = .01). The MST for Groups 1 and 2 after ureteral decompression was 923 and 762 days, respectively (P = .62), with the MST for death secondary to kidney disease in both groups being >1,442 days. Re-obstruction was the most common complication in Group 1 (24%) occurring more commonly in ureters of cats treated with a ureteral stent(s) (44%) compared to the subcutaneous ureteral bypass (SUB) device (8%) (P = .01). Ureteral obstructions in cats with a CU(s) have a similar outcome to those cats with a ureteral obstruction and normal ureteral anatomy. Long-term prognosis is good for benign ureteral obstructions treated with a double pigtail stent or a SUB device. The SUB device re-obstructed less commonly than the ureteral stent, especially when a ureteral stricture was present. Copyright © 2014 by the American College of Veterinary Internal Medicine.

Clinical Outcomes of Self-Expandable Metal Stents for Malignant Rectal Obstruction.

PubMed

Lee, Hyun Jung; Hong, Sung Pil; Cheon, Jae Hee; Kim, Tae Il; Kim, Won Ho; Park, Soo Jung

2018-01-01

Self-expandable metal stents are widely used to treat malignant colorectal obstruction. However, data on clinical outcomes of stent placement for rectal obstruction specifically are lacking. We aimed to investigate the clinical outcomes of self-expandable metal stents in malignant rectal obstruction in comparison with those in left colonic obstruction and to identify factors associated with clinical failure and complication. This was a retrospective study. The study was conducted at a tertiary care center. Between January 2005 and December 2013, medical charts of patients who underwent stent placement for malignant rectal or left colonic obstruction were reviewed retrospectively. Study intervention included self-expandable metal stent placement. Technical success, clinical success, and complications were measured. Technical success rates for the 2 study groups (rectum vs left colon, 93.5% vs 93.1%; p = 0.86) did not differ significantly; however, the clinical success rate was lower in patients with rectal obstruction (85.4% vs 92.1%; p = 0.02). In addition, the complication rate was higher in patients with rectal obstruction (37.4% vs 25.1%; p = 0.01). Patients with rectal obstruction showed higher rates of obstruction because of extracolonic malignancy (33.8% vs 15.8%; p < 0.001) and stent use for palliation (78.6% vs 56.3%; p < 0.001). Multivariate analysis indicated obstruction attributed to extracolonic malignancy and covered stent usage to be independent risk factors for clinical failure. Factors predictive of complications in the palliative group were total obstruction, obstruction because of extracolonic malignancy, and covered stent usage. This was a retrospective, single-center study. The efficacy and safety of stent placement for malignant rectal obstruction were comparable with those for left colonic obstruction. However, obstruction attributed to extracolonic malignancy, use of covered stents, and total obstruction negatively impacted clinical outcomes of self-expandable metal stent placement and must be considered by endoscopists. See Video Abstract at http://links.lww.com/DCR/A417.

[A case of gastric outlet obstruction and rectal obstruction due to metastases from breast cancer treated by gastroduodenal and colon stenting].

PubMed

Morimoto, Yoshihiro; Egawa, Chiyomi; Ishida, Tomo; Sato, Yasufumi; Kusama, Hiroki; Hashimoto, Tadayoshi; Matsushita, Katsunori; Kimura, Kei; Katsura, Yoshiteru; Nitta, Kanae; Kagawa, Yoshinori; Okishiro, Masatsugu; Takeno, Atsushi; Nakahira, Shin; Sakisaka, Hideki; Taniguchi, Hirokazu; Takeda, Yutaka; Kato, Takeshi; Tamura, Shigeyuki; Takatsuka, Yuichi

2014-11-01

Malignant bowel obstruction often causes oral intake difficulties and decreases quality of life. In Japan, gastroduodenal stenting for malignant gastric outlet obstruction has been covered by health insurance since 2010, while colon stenting has been covered since 2012. Both approaches are useful treatments for malignant bowel obstruction. Here we report the case of a woman with gastric outlet obstruction and rectal obstruction due to breast cancer metastases who was able to eat solid food after duodenal and colon stenting. When choosing whether to perform endoscopic stenting or surgical intervention such as gastrojejunostomy, ileostomy, and colostomy for treating malignant bowel obstruction, it is important to assess the patient's general condition and prognosis as well as the obstruction position.

Utility of CT in the diagnosis and management of small-bowel obstruction in children.

PubMed

Wang, Qiuyan; Chavhan, Govind B; Babyn, Paul S; Tomlinson, George; Langer, Jacob C

2012-12-01

CT is often used in the diagnosis and management of small-bowel obstruction in children. To determine sensitivity of CT in delineating presence, site and cause of small-bowel obstruction in children. We retrospectively reviewed the CT scans of 47 children with surgically proven small-bowel obstruction. We noted any findings of obstruction and the site and cause of obstruction. Presence, absence or equivocal findings of bowel obstruction on abdominal radiographs performed prior to CT were also noted. We reviewed patient charts for clinical details and surgical findings, including bowel resection. Statistical analysis was performed using Fisher exact test to determine which CT findings might predict bowel resection. CT correctly diagnosed small-bowel obstruction in 43/47 (91.5%) cases. CT correctly indicated site of obstruction in 37/47 (78.7%) cases and cause of obstruction in 32/47 (68.1%) cases. Small-bowel feces sign was significantly associated with bowel resection at surgery (P = 0.0091). No other CT finding was predictive of bowel resection. Out of 41 children who had abdominal radiographs before CT, 29 (70.7%) showed unequivocal obstruction, six (14.6%) showed equivocal findings and six (14.6%) were unremarkable. CT is highly sensitive in diagnosing small-bowel obstruction in children and is helpful in determining the presence of small-bowel obstruction in many clinically suspected cases with equivocal or normal plain radiographs. CT also helps to determine the site and cause of the obstruction with good sensitivity.

Reduced upper obstructions in N3 and increased lower obstructions in REM sleep stage detected with manometry.

PubMed

Wirth, Markus; Schramm, Juliane; Bautz, Maximilian; Hofauer, Benedikt; Edenharter, Günther; Ott, Armin; Heiser, Clemens

2018-01-01

In obstructive sleep apnea (OSA), airway obstruction occurs at different anatomic levels. The frequency and location of obstructions play a crucial role in the planning of surgical treatment. The aim of this study was to evaluate the pharyngeal obstruction levels in different sleep stages with manometry in OSA patients. In addition, the manometry results were compared with drug-induced sleep endoscopy (DISE). Forty-one patients with OSA received manometry measurements during one night of sleep. All patients were simultaneously evaluated with polysomnography. The frequency of obstructions in different sleep stages was assessed. Twenty patients were additionally studied with DISE. Obstruction levels detected with manometry were compared with DISE. The frequency of upper and to a lesser extent lower obstructions decreased in sleep stage N3. In rapid eye movement (REM) sleep, lower obstructions increased. The overall proportion of upper and lower obstructions detected with manometry corresponded with DISE in 13 of 20 cases. A significant change in the obstruction levels was detected with manometry in N3 and REM sleep. The reduction of both upper and to a lesser extent lower obstructions in N3 suggests more stable airways in slow-wave sleep. Relevant lower obstructions were not detected in DISE compared to manometry in 5 out of 20 examinations. This could be a potential reason for treatment failure of site-specific surgical OSA treatment when only performing DISE preoperatively. Therefore, manometry could be a useful complementary tool in the preoperative evaluation for OSA.

1.00 MeV proton radiation resistance studies of single-junction and single gap dual-junction amorphous-silicon alloy solar cells

NASA Technical Reports Server (NTRS)

Abdulaziz, Salman; Payson, J. S.; Li, Yang; Woodyard, James R.

1990-01-01

A comparative study of the radiation resistance of a-Si:H and a-SiGe:H single-junction and a-Si:H dual-junction solar cells was conducted. The cells were irradiated with 1.00-MeV protons with fluences of 1.0 x 10 to the 14th, 5.0 x 10 to the 14th and 1.0 x 10 to the 15th/sq cm and characterized using I-V and quantum efficiency measurements. The radiation resistance of single-junction cells cannot be used to explain the behavior of dual-junction cells at a fluence of 1.0 x 10 to the 15th/sq cm. The a-Si H single-junction cells degraded the least of the three cells; a-SiGe:H single-junction cells showed the largest reduction in short-circuit current, while a-Si:H dual-junction cells exhibited the largest degradation in the open-circuit voltage. The quantum efficiency of the cells degraded more in the red part of the spectrum; the bottom junction degrades first in dual-junction cells.

Fabrication of magnetic tunnel junctions with epitaxial and textured ferromagnetic layers

DOEpatents

Chang, Y. Austin; Yang, Jianhua Joshua

2008-11-11

This invention relates to magnetic tunnel junctions and methods for making the magnetic tunnel junctions. The magnetic tunnel junctions include a tunnel barrier oxide layer sandwiched between two ferromagnetic layers both of which are epitaxial or textured with respect to the underlying substrate upon which the magnetic tunnel junctions are grown. The magnetic tunnel junctions provide improved magnetic properties, sharper interfaces and few defects.

Possible involvement of gap junctions in the barrier function of tight junctions of brain and lung endothelial cells.

PubMed

Nagasawa, Kunihiko; Chiba, Hideki; Fujita, Hiroki; Kojima, Takashi; Saito, Tsuyoshi; Endo, Toshiaki; Sawada, Norimasa

2006-07-01

Gap-junction plaques are often observed with tight-junction strands of vascular endothelial cells but the molecular interaction and functional relationships between these two junctions remain obscure. We herein show that gap-junction proteins connexin40 (Cx40) and Cx43 are colocalized and coprecipitated with tight-junction molecules occludin, claudin-5, and ZO-1 in porcine blood-brain barrier (BBB) endothelial cells. Gap junction blockers 18beta-glycyrrhetinic acid (18beta-GA) and oleamide (OA) did not influence expression of Cx40, Cx43, occludin, claudin-5, junctional adhesion molecule (JAM)-A, JAM-B, JAM-C, or ZO-1, or their subcellular localization in the porcine BBB endothelial cells. In contrast, these gap-junction blocking agents inhibited the barrier function of tight junctions in cells, determined by measurement of transendothelial electrical resistance and paracellular flux of mannitol and inulin. 18beta-GA also significantly reduced the barrier property in rat lung endothelial (RLE) cells expressing doxycycline-induced claudin-1, but did not change the interaction between Cx43 and either claudin-1 or ZO-1, nor their expression levels or subcellular distribution. These findings suggest that Cx40- and/or Cx43-based gap junctions might be required to maintain the endothelial barrier function without altering the expression and localization of the tight-junction components analyzed. Copyright 2006 Wiley-Liss, Inc.

Research and develop locking design for NJDOT junction boxes : final report, April 2009.

DOT National Transportation Integrated Search

2009-04-01

The report outlines the guidelines for securing electrical junction box covers to the junction box to prevent vandalism. The report provides details drawings that show various methods for securing the junction box cover to the junction box.

Four-junction superconducting circuit

PubMed Central

Qiu, Yueyin; Xiong, Wei; He, Xiao-Ling; Li, Tie-Fu; You, J. Q.

2016-01-01

We develop a theory for the quantum circuit consisting of a superconducting loop interrupted by four Josephson junctions and pierced by a magnetic flux (either static or time-dependent). In addition to the similarity with the typical three-junction flux qubit in the double-well regime, we demonstrate the difference of the four-junction circuit from its three-junction analogue, including its advantages over the latter. Moreover, the four-junction circuit in the single-well regime is also investigated. Our theory provides a tool to explore the physical properties of this four-junction superconducting circuit. PMID:27356619

Intercellular junctions between palisade nerve endings and outer root sheath cells of rat vellus hairs.

PubMed

Kaidoh, T; Inoué, T

2000-05-15

Hair follicles have a longitudinal set of sensory nerve endings called palisade nerve endings (PN). We examined the junctional structures between the PN and outer root sheath (ORS) cells of hair follicles in the rat external ear. Transmission electron microscopy of serial thin sections showed that the processes of the ORS cells penetrated the basal lamina of the hair follicle, forming intercellular junctions with the PN (PN-ORS junctions). Two types of junctions were found: junctions between nerve endings and ORS cells (N-ORS junctions) and those between Schwann cell processes and ORS cells (S-ORS junctions). The N-ORS junctions had two subtypes: 1) a short process or small eminence of the ORS cell was attached to the nerve ending (type I); or 2) a process of the ORS cell was invaginated into the nerve ending (type II). The S-ORS junctions also had two subtypes: 1) a short process or small eminence of the ORS cell was abutted on the Schwann cell process (type I); or 2) a process of the ORS cell was invaginated into the Schwann cell process (type II). Vesicles, coated pits, coated vesicles, and endosomes were sometimes seen in nerve endings, Schwann cells, and ORS cells near the junctions. Computer-aided reconstruction of the serial thin sections displayed the three-dimensional structure of these junctions. These results suggested that the PN-ORS junctions provided direct relationships between the PN and ORS in at least four different patterns. The discovery of these junctions shows the PN-ORS relationship to be closer than previously realized. We speculate that these junctions may have roles in attachment of the PN to the ORS, contributing to increases in the sensitivity of the PN, and in chemical signaling between the PN and ORS.

Value of gastrografin in adhesive small bowel obstruction after unsuccessful conservative treatment: a prospective evaluation.

PubMed

Choi, Hok-Kwok; Law, Wai-Lun; Ho, Judy-Wai-Chu; Chu, Kin-Wah

2005-06-28

Gastrografin is a hyperosmolar water-soluble contrast medium. Besides its predictive value for the need for operative treatment, a potential therapeutic role of this agent in adhesive small bowel obstruction has been suggested. This study aimed at evaluating the effectiveness of gastrografin in adhesive small bowel obstruction when conservative treatment failed. Patients with adhesive small bowel obstruction were given trial conservative treatment unless there was fear of bowel strangulation. Those responded in the initial 48 h had conservative treatment continued. Patients who showed no improvement in the initial 48 h were given 100 mL of gastrografin through nasogastric tube followed by serial abdominal radiographs. Patients with the contrast appeared in large bowel within 24 h were regarded as having partial obstruction and conservative treatment was continued. Patients in which the contrast failed to reach large bowel within 24 h were considered to have complete obstruction and laparotomy was performed. Two hundred and twelve patients with 245 episodes of adhesive obstruction were included. Fifteen patients were operated on soon after admission due to fear of strangulation. One hundred and eighty-six episodes of obstruction showed improvement in the initial 48 h and conservative treatment was continued. Two patients had subsequent operations because of persistent obstruction. Forty-four episodes of obstruction showed no improvement within 48 h and gastrografin was administered. Seven patients underwent complete obstruction surgery. Partial obstruction was demonstrated in 37 other cases, obstruction resolved subsequently in all of them except one patient who required laparotomy because of persistent obstruction. The overall operative rate in this study was 10%. There was no complication that could be attributed to the use of gastrografin. The use of gastrografin in adhesive small bowel obstruction after unsuccessful conservative treatment is safe and reduces the need for surgical intervention.

Superstrate sub-cell voltage-matched multijunction solar cells

DOEpatents

Mascarenhas, Angelo; Alberi, Kirstin

2016-03-15

Voltage-matched thin film multijunction solar cell and methods of producing cells having upper CdTe pn junction layers formed on a transparent substrate which in the completed device is operatively positioned in a superstate configuration. The solar cell also includes a lower pn junction formed independently of the CdTe pn junction and an insulating layer between CdTe and lower pn junctions. The voltage-matched thin film multijunction solar cells further include a parallel connection between the CdTe pn junction and lower pn junctions to form a two-terminal photonic device. Methods of fabricating devices from independently produced upper CdTe junction layers and lower junction layers are also disclosed.

Small Bowel Obstruction Caused by Aloe vera Bezoars: A Case Report.

PubMed

Hong, In Taik; Cha, Jae Myung; Ki, Hye Jin; Kwak, Min Seob; Yoon, Jin Young; Shin, Hyun Phil; Jeoun, Jung Won; Choi, Sung Il

2017-05-25

Small bowel obstruction is a clinical condition commonly caused by postoperative adhesion, volvulus, intussusceptions, and hernia. Small bowel obstruction due to bezoars is clinically uncommon, accounting for approximately 2-4% of all obstructions. Computed tomography (CT) is a useful method in diagnosing the cause of small bowel obstruction. However, small bowel obstruction caused by bezoars may not be detected by an abdominal CT examination. Herein, we report a rare case of small bowel obstruction by Aloe vera bezoars, which were undetected by an abdominal CT. Phytobezoars should be included in the differential diagnosis of small bowel obstruction in patients with predisposing factors, such as excessive consumption of high-fiber food and diabetes.

Effect of solar-cell junction geometry on open-circuit voltage

NASA Technical Reports Server (NTRS)

Weizer, V. G.; Godlewski, M. P.

1985-01-01

Simple analytical models have been found that adequately describe the voltage behavior of both the stripe junction and dot junction grating cells as a function of junction area. While the voltage in the former case is found to be insensitive to junction area reduction, significant voltage increases are shown to be possible for the dot junction cell. With regard to cells in which the junction area has been increased in a quest for better performance, it was found that (1) texturation does not affect the average saturation current density J0, indicating that the texturation process is equivalent to a simple extension of junction area by a factor of square root of 3 and (2) the vertical junction cell geometry produces a sizable decrease in J0 that, unfortunately, is more than offset by the effects of attendant areal increases.

Anisotropic-Scale Junction Detection and Matching for Indoor Images.

PubMed

Xue, Nan; Xia, Gui-Song; Bai, Xiang; Zhang, Liangpei; Shen, Weiming

Junctions play an important role in characterizing local geometrical structures of images, and the detection of which is a longstanding but challenging task. Existing junction detectors usually focus on identifying the location and orientations of junction branches while ignoring their scales, which, however, contain rich geometries of images. This paper presents a novel approach for junction detection and characterization, which especially exploits the locally anisotropic geometries of a junction and estimates its scales by relying on an a-contrario model. The output junctions are with anisotropic scales, saying that a scale parameter is associated with each branch of a junction and are thus named as anisotropic-scale junctions (ASJs). We then apply the new detected ASJs for matching indoor images, where there are dramatic changes of viewpoints and the detected local visual features, e.g., key-points, are usually insufficient and lack distinctive ability. We propose to use the anisotropic geometries of our junctions to improve the matching precision of indoor images. The matching results on sets of indoor images demonstrate that our approach achieves the state-of-the-art performance on indoor image matching.Junctions play an important role in characterizing local geometrical structures of images, and the detection of which is a longstanding but challenging task. Existing junction detectors usually focus on identifying the location and orientations of junction branches while ignoring their scales, which, however, contain rich geometries of images. This paper presents a novel approach for junction detection and characterization, which especially exploits the locally anisotropic geometries of a junction and estimates its scales by relying on an a-contrario model. The output junctions are with anisotropic scales, saying that a scale parameter is associated with each branch of a junction and are thus named as anisotropic-scale junctions (ASJs). We then apply the new detected ASJs for matching indoor images, where there are dramatic changes of viewpoints and the detected local visual features, e.g., key-points, are usually insufficient and lack distinctive ability. We propose to use the anisotropic geometries of our junctions to improve the matching precision of indoor images. The matching results on sets of indoor images demonstrate that our approach achieves the state-of-the-art performance on indoor image matching.

High-efficiency solar cell and method for fabrication

DOEpatents

Hou, Hong Q.; Reinhardt, Kitt C.

1999-01-01

A high-efficiency 3- or 4-junction solar cell is disclosed with a theoretical AM0 energy conversion efficiency of about 40%. The solar cell includes p-n junctions formed from indium gallium arsenide nitride (InGaAsN), gallium arsenide (GaAs) and indium gallium aluminum phosphide (InGaAlP) separated by n-p tunnel junctions. An optional germanium (Ge) p-n junction can be formed in the substrate upon which the other p-n junctions are grown. The bandgap energies for each p-n junction are tailored to provide substantially equal short-circuit currents for each p-n junction, thereby eliminating current bottlenecks and improving the overall energy conversion efficiency of the solar cell. Additionally, the use of an InGaAsN p-n junction overcomes super-bandgap energy losses that are present in conventional multi-junction solar cells. A method is also disclosed for fabricating the high-efficiency 3- or 4-junction solar cell by metal-organic chemical vapor deposition (MOCVD).

High-efficiency solar cell and method for fabrication

DOEpatents

Hou, H.Q.; Reinhardt, K.C.

1999-08-31

A high-efficiency 3- or 4-junction solar cell is disclosed with a theoretical AM0 energy conversion efficiency of about 40%. The solar cell includes p-n junctions formed from indium gallium arsenide nitride (InGaAsN), gallium arsenide (GaAs) and indium gallium aluminum phosphide (InGaAlP) separated by n-p tunnel junctions. An optional germanium (Ge) p-n junction can be formed in the substrate upon which the other p-n junctions are grown. The bandgap energies for each p-n junction are tailored to provide substantially equal short-circuit currents for each p-n junction, thereby eliminating current bottlenecks and improving the overall energy conversion efficiency of the solar cell. Additionally, the use of an InGaAsN p-n junction overcomes super-bandgap energy losses that are present in conventional multi-junction solar cells. A method is also disclosed for fabricating the high-efficiency 3- or 4-junction solar cell by metal-organic chemical vapor deposition (MOCVD). 4 figs.

[Influence of Cx26/Cx32 gap junction channel on antineoplastic effect of etoposide in Hela cells].

PubMed

Tong, Xu-Hui; Dong, Shu-Ying; Jiang, Guo-Jun; Fan, Gao-Fu

2012-03-01

To observe the influence of Cx26/Cx32 gap junction channel on the antineoplastic effect of etoposide in Hela cervical cancer cells. Fluorescence trace was used to assay the gap junction intercellular communication mediated by Cx26/Cx32 in Hela cells and its functional modulation by the pharmacological agents (oleamide, retinoid acid). A standard colony-forming assay was applied to determine the cell growth-inhibiting effect of etoposide in Hela cells with functional modulation of the gap junction. Hoechst 33258 staining was used to assess the changes in etoposide-induced apoptosis of Hela cells with altered gap junction functions. Oleamide markedly decreased while retinoid acid obviously increased the gap junction function in Hela cells. Standard colony-forming assay showed that etoposide produced a lowered antiproliferative effect in Hela cells with reduced gap junction and an increased antiproliferative effect in cells with enhanced gap junction function. In cells with a reduced gap junction function, etoposide induced a lowered apoptosis rate, which increased obviously in cells with an enhanced gap junction function. The antineoplastic effect of etoposide is reduced in Hela cells with a decreased gap junction intercellular communication mediated by Cx26/Cx32 and is enhanced in cells with an increased gap junction intercellular communication.

Effects of 18beta-glycyrrhetinic acid on the junctional complex and steroidogenesis in rat adrenocortical cells.

PubMed

Huang, Shih-Horng; Wu, Jiahn-Chun; Hwang, Ra-Der; Yeo, Hui-Lin; Wang, Seu-Mei

2003-09-01

Cellular junctions play important roles in cell differentiation, signal transduction, and cell function. This study investigated their function in steroid secretion by adrenal cells. Immunofluorescence staining revealed the presence of gap junctions and adherens junctions between adrenal cells. The major gap junction protein, connexin43, was seen as a linear dotted pattern of the typical gap junction plaques, in contrast to alpha-, beta-, and gamma-catenin, which were seen as continuous, linear staining of cell-cell adherens junction. Treatment with 18beta-glycyrrhetinic acid, a gap junction inhibitor, reduced the immunoreactivity of these proteins in a time- and dose-dependent manner, and caused the gap junction and adherens junction to separate longitudinally from the cell-cell contact sites, indicating the structural interdependency of these two junctions. Interestingly, 18beta-glycyrrhetinic acid stimulated a two- to three-fold increase in steroid production in these adrenal cells lacking intact cell junctions. These data raise the question of the necessity for cell communication for the endocrine function of adrenal cells. Pharmacological analyses indicated that the steroidogenic effect of 18beta-glycyrrhetinic acid was partially mediated by extracellular signal-related kinase and calcium/calmodulin-dependent kinase, a pathway distinct from the protein kinase A signaling pathway already known to mediate steroidogenesis in adrenal cells. Copyright 2003 Wiley-Liss, Inc.

Gap junctions modulate glioma invasion by direct transfer of microRNA.

PubMed

Hong, Xiaoting; Sin, Wun Chey; Harris, Andrew L; Naus, Christian C

2015-06-20

The invasiveness of high-grade glioma is the primary reason for poor survival following treatment. Interaction between glioma cells and surrounding astrocytes are crucial to invasion. We investigated the role of gap junction mediated miRNA transfer in this context. By manipulating gap junctions with a gap junction inhibitor, siRNAs, and a dominant negative connexin mutant, we showed that functional glioma-glioma gap junctions suppress glioma invasion while glioma-astrocyte and astrocyte-astrocyte gap junctions promote it in an in vitro transwell invasion assay. After demonstrating that glioma-astrocyte gap junctions are permeable to microRNA, we compared the microRNA profiles of astrocytes before and after co-culture with glioma cells, identifying specific microRNAs as candidates for transfer through gap junctions from glioma cells to astrocytes. Further analysis showed that transfer of miR-5096 from glioma cells to astrocytes is through gap junctions; this transfer is responsible, in part, for the pro-invasive effect. Our results establish a role for glioma-astrocyte gap junction mediated microRNA signaling in modulation of glioma invasive behavior, and that gap junction coupling among astrocytes magnifies the pro-invasive signaling. Our findings reveal the potential for therapeutic interventions based on abolishing alteration of stromal cells by tumor cells via manipulation of microRNA and gap junction channel activity.

Gap junctions modulate glioma invasion by direct transfer of microRNA

PubMed Central

Hong, Xiaoting; Sin, Wun Chey; Harris, Andrew L.; Naus, Christian C.

2015-01-01

The invasiveness of high-grade glioma is the primary reason for poor survival following treatment. Interaction between glioma cells and surrounding astrocytes are crucial to invasion. We investigated the role of gap junction mediated miRNA transfer in this context. By manipulating gap junctions with a gap junction inhibitor, siRNAs, and a dominant negative connexin mutant, we showed that functional glioma-glioma gap junctions suppress glioma invasion while glioma-astrocyte and astrocyte-astrocyte gap junctions promote it in an in vitro transwell invasion assay. After demonstrating that glioma-astrocyte gap junctions are permeable to microRNA, we compared the microRNA profiles of astrocytes before and after co-culture with glioma cells, identifying specific microRNAs as candidates for transfer through gap junctions from glioma cells to astrocytes. Further analysis showed that transfer of miR-5096 from glioma cells to astrocytes is through gap junctions; this transfer is responsible, in part, for the pro-invasive effect. Our results establish a role for glioma-astrocyte gap junction mediated microRNA signaling in modulation of glioma invasive behavior, and that gap junction coupling among astrocytes magnifies the pro-invasive signaling. Our findings reveal the potential for therapeutic interventions based on abolishing alteration of stromal cells by tumor cells via manipulation of microRNA and gap junction channel activity. PMID:25978028

CSReport: A New Computational Tool Designed for Automatic Analysis of Class Switch Recombination Junctions Sequenced by High-Throughput Sequencing.

PubMed

Boyer, François; Boutouil, Hend; Dalloul, Iman; Dalloul, Zeinab; Cook-Moreau, Jeanne; Aldigier, Jean-Claude; Carrion, Claire; Herve, Bastien; Scaon, Erwan; Cogné, Michel; Péron, Sophie

2017-05-15

B cells ensure humoral immune responses due to the production of Ag-specific memory B cells and Ab-secreting plasma cells. In secondary lymphoid organs, Ag-driven B cell activation induces terminal maturation and Ig isotype class switch (class switch recombination [CSR]). CSR creates a virtually unique IgH locus in every B cell clone by intrachromosomal recombination between two switch (S) regions upstream of each C region gene. Amount and structural features of CSR junctions reveal valuable information about the CSR mechanism, and analysis of CSR junctions is useful in basic and clinical research studies of B cell functions. To provide an automated tool able to analyze large data sets of CSR junction sequences produced by high-throughput sequencing (HTS), we designed CSReport, a software program dedicated to support analysis of CSR recombination junctions sequenced with a HTS-based protocol (Ion Torrent technology). CSReport was assessed using simulated data sets of CSR junctions and then used for analysis of Sμ-Sα and Sμ-Sγ1 junctions from CH12F3 cells and primary murine B cells, respectively. CSReport identifies junction segment breakpoints on reference sequences and junction structure (blunt-ended junctions or junctions with insertions or microhomology). Besides the ability to analyze unprecedentedly large libraries of junction sequences, CSReport will provide a unified framework for CSR junction studies. Our results show that CSReport is an accurate tool for analysis of sequences from our HTS-based protocol for CSR junctions, thereby facilitating and accelerating their study. Copyright © 2017 by The American Association of Immunologists, Inc.

Regulation of gap junctional charge selectivity in cells coexpressing connexin 40 and connexin 43.

PubMed

Heyman, Nathanael S; Kurjiaka, David T; Ek Vitorin, Jose F; Burt, Janis M

2009-07-01

Expression of connexin 40 (Cx40) and Cx43 in cardiovascular tissues varies as a function of age, injury, and development with unknown consequences on the selectivity of junctional communication and its acute regulation. We investigated the PKC-dependent regulation of charge selectivity in junctions composed of Cx43, Cx40, or both by simultaneous assessment of junctional permeance rate constants (B(dye)) for dyes of similar size but opposite charge, N,N,N-trimethyl-2-[methyl-(7-nitro-2,1,3-benzoxadiol-4-yl)amino]ethanaminium (NBD-M-TMA; +1) and Alexa 350 (-1). The ratio of dye rate constants (B(NBD-M-TMA)/B(Alexa 350)) indicated that Cx40 junctions are cation selective (10.7 +/- 0.5), whereas Cx43 junction are nonselective (1.22 +/- 0.14). In coexpressing cells, a broad range of junctional selectivities was observed with mean cation selectivity increasing as the Cx40 to Cx43 expression ratio increased. PKC activation reduced or eliminated dye permeability of Cx43 junctions without altering their charge selectivity, had no effect on either permeability or charge selectivity of Cx40 junctions, and significantly increased the cation selectivity of junctions formed by coexpressing cells (approaching charge selectivity of Cx40 junctions). Junctions composed of Cx43 truncated at residue 257 (Cx43tr) were also not charge selective, but when Cx43tr was coexpressed with Cx40, a broad range of junctional selectivities that was unaffected by PKC activation was observed. Thus, whereas the charge selectivities of homomeric/homotypic Cx43 and Cx40 junctions appear invariant, the selectivities of junctions formed by cells coexpressing Cx40 and Cx43 vary considerably, reflecting both their relative expression levels and phosphorylation-dependent regulation. Such regulation could represent a mechanism by which coexpressing cells such as vascular endothelium and atrial cells regulate acutely the selective intercellular communication mediated by their gap junctions.

Palliation double stenting for malignant biliary and duodenal obstruction

PubMed Central

ZHAO, LIANG; XU, HAITAO; ZHANG, YUBAO

2016-01-01

The surgical management of patients with malignant biliary and duodenal obstruction is complex. Tumor excision is no longer possible in the majority of patients with malignant obstructive jaundice and duodenal obstruction. The aim of the present study was to evaluate the effectiveness of intraluminal dual stent placement in malignant biliary and duodenal obstruction. In total, 20 patients with malignant obstructive jaundice and duodenal obstruction, including 6 with pancreatic carcinoma, 11 with cholangiocarcinoma, 1 with duodenal carcinoma and 2 with abdominal lymph node metastasis, were treated with intraluminal stent placement. Bile duct obstruction with late occurrence of duodenal obstruction was observed in 16 cases, and duodenal obstruction followed by a late occurrence of bile duct obstruction was observed in 3 cases, while, in 1 case, bile duct obstruction and duodenal obstruction occurred simultaneously. After X-ray fluoroscopy revealed obstruction in the bile duct and duodenum, stents were placed into the respective lumens. Percutaneous transhepatic placement was employed for the biliary stent, while the duodenal stent was placed perioraly. The clinical outcomes, including complications associated with the procedures and patency of the stents, were evaluated. The biliary and duodenal stents were successfully implanted in 18 patients and the technical success rate was 90% (18/20). A total of 39 stents were implanted in 20 patients. In 2 cases, duodenal stent placement failed following biliary stent placement. Duodenal obstruction remitted in 15 patients, and 1 patient succumbed to aspiration pneumonia 5 days after the procedure. No severe complications were observed in any other patient. The survival time of the 18 patients was 5–21 months (median, 9.6 months), and 6 of those patients survived for >12 months. The present study suggests that X-ray fluoroscopy-guided intraluminal stent implantation is an effective procedure for the treatment of malignant biliary and duodenal obstruction. PMID:26889267

Method of making high breakdown voltage semiconductor device

DOEpatents

Arthur, Stephen D.; Temple, Victor A. K.

1990-01-01

A semiconductor device having at least one P-N junction and a multiple-zone junction termination extension (JTE) region which uniformly merges with the reverse blocking junction is disclosed. The blocking junction is graded into multiple zones of lower concentration dopant adjacent termination to facilitate merging of the JTE to the blocking junction and placing of the JTE at or near the high field point of the blocking junction. Preferably, the JTE region substantially overlaps the graded blocking junction region. A novel device fabrication method is also provided which eliminates the prior art step of separately diffusing the JTE region.

Methods for the fabrication of thermally stable magnetic tunnel junctions

DOEpatents

Chang, Y Austin [Middleton, WI; Yang, Jianhua J [Madison, WI; Ladwig, Peter F [Hutchinson, MN

2009-08-25

Magnetic tunnel junctions and method for making the magnetic tunnel junctions are provided. The magnetic tunnel junctions are characterized by a tunnel barrier oxide layer sandwiched between two ferromagnetic layers. The methods used to fabricate the magnetic tunnel junctions are capable of completely and selectively oxidizing a tunnel junction precursor material using an oxidizing gas containing a mixture of gases to provide a tunnel junction oxide without oxidizing the adjacent ferromagnetic materials. In some embodiments the gas mixture is a mixture of CO and CO.sub.2 or a mixture of H.sub.2 and H.sub.2O.

Possible Involvement of Tight Junctions, Extracellular Matrix and Nuclear Receptors in Epithelial Differentiation

PubMed Central

Ichikawa-Tomikawa, Naoki; Sugimoto, Kotaro; Satohisa, Seiro; Nishiura, Keisuke; Chiba, Hideki

2011-01-01

Tight junctions are intercellular junctions localized at the most apical end of the lateral plasma membrane. They consist of four kinds of transmembrane proteins (occludin, claudins, junctional adhesion molecules, and tricellulin) and huge numbers of scaffolding proteins and contribute to the paracellular barrier and fence function. The mutation and deletion of these proteins impair the functions of tight junctions and cause various human diseases. In this paper, we provide an overview of recent studies on transmembrane proteins of tight junctions and highlight the functional significance of tight junctions, extracellular matrix, and nuclear receptors in epithelial differentiation. PMID:22162632

Gap junction- and hemichannel-independent actions of connexins.

PubMed

Jiang, Jean X; Gu, Sumin

2005-06-10

Connexins have been known to be the protein building blocks of gap junctions and mediate cell-cell communication. In contrast to the conventional dogma, recent evidence suggests that in addition to forming gap junction channels, connexins possess gap junction-independent functions. One important gap junction-independent function for connexins is to serve as the major functional component for hemichannels, the un-apposed halves of gap junctions. Hemichannels, as independent functional units, play roles that are different from that of gap junctions in the cell. The other functions of connexins appear to be gap junction- and hemichannel-independent. Published studies implicate the latter functions of connexins in cell growth, differentiation, tumorigenicity, injury, and apoptosis, although the mechanistic aspects of these actions remain largely unknown. In this review, gap junction- and hemichannel-independent functions of connexins are summarized, and the molecular mechanisms underlying these connexin functions are speculated and discussed.

Atomic-scaled characterization of graphene PN junctions

NASA Astrophysics Data System (ADS)

Zhou, Xiaodong; Wang, Dennis; Dadgar, Ali; Agnihotri, Pratik; Lee, Ji Ung; Reuter, Mark C.; Ross, Frances M.; Pasupathy, Abhay N.

Graphene p-n junctions are essential devices for studying relativistic Klein tunneling and the Veselago lensing effect in graphene. We have successfully fabricated graphene p-n junctions using both lithographically pre-patterned substrates and the stacking of vertical heterostructures. We then use our 4-probe STM system to characterize the junctions. The ability to carry out scanning electron microscopy (SEM) in our STM instrument is essential for us to locate and measure the junction interface. We obtain both the topography and dI/dV spectra at the junction area, from which we track the shift of the graphene chemical potential with position across the junction interface. This allows us to directly measure the spatial width and roughness of the junction and its potential barrier height. We will compare the junction properties of devices fabricated by the aforementioned two methods and discuss their effects on the performance as a Veselago lens.

Molecular mechanisms regulating formation, trafficking and processing of annular gap junctions.

PubMed

Falk, Matthias M; Bell, Cheryl L; Kells Andrews, Rachael M; Murray, Sandra A

2016-05-24

Internalization of gap junction plaques results in the formation of annular gap junction vesicles. The factors that regulate the coordinated internalization of the gap junction plaques to form annular gap junction vesicles, and the subsequent events involved in annular gap junction processing have only relatively recently been investigated in detail. However it is becoming clear that while annular gap junction vesicles have been demonstrated to be degraded by autophagosomal and endo-lysosomal pathways, they undergo a number of additional processing events. Here, we characterize the morphology of the annular gap junction vesicle and review the current knowledge of the processes involved in their formation, fission, fusion, and degradation. In addition, we address the possibility for connexin protein recycling back to the plasma membrane to contribute to gap junction formation and intercellular communication. Information on gap junction plaque removal from the plasma membrane and the subsequent processing of annular gap junction vesicles is critical to our understanding of cell-cell communication as it relates to events regulating development, cell homeostasis, unstable proliferation of cancer cells, wound healing, changes in the ischemic heart, and many other physiological and pathological cellular phenomena.

ABUNDANCE AND ULTRASTRUCTURAL DIVERSITY OF NEURONAL GAP JUNCTIONS IN THE OFF AND ON SUBLAMINAE OF THE INNER PLEXIFORM LAYER OF RAT AND MOUSE RETINA

PubMed Central

KAMASAWA, N.; FURMAN, C. S.; DAVIDSON, K. G. V.; SAMPSON, J. A.; MAGNIE, A. R.; GEBHARDT, B. R.; KAMASAWA, M.; YASUMURA, T.; ZUMBRUNNEN, J. R.; PICKARD, G. E.; NAGY, J. I.; RASH, J. E.

2007-01-01

Neuronal gap junctions are abundant in both outer and inner plexiform layers of the mammalian retina. In the inner plexiform layer (IPL), ultrastructurally-identified gap junctions were reported primarily in the functionally-defined and anatomically-distinct ON sublamina, with few reported in the OFF sublamina. We used freeze-fracture replica immunogold labeling and confocal microscopy to quantitatively analyze the morphologies and distributions of neuronal gap junctions in the IPL of adult rat and mouse retina. Under “baseline” conditions (photopic illumination/general anesthesia), 649 neuronal gap junctions immunogold-labeled for connexin36 were identified in rat IPL, of which 375 were photomapped to OFF vs. ON sublaminae. In contrast to previous reports, the volume-density of gap junctions was equally abundant in both sublaminae. Five distinctive morphologies of gap junctions were identified: conventional crystalline and non-crystalline “plaques” (71% and 3%), plus unusual “string” (14%), “ribbon” (7%) and “reticular” (2%) forms. Plaque and reticular gap junctions were distributed throughout the IPL. However, string and ribbon gap junctions were restricted to the OFF sublamina, where they represented 48% of gap junctions in that layer. In string and ribbon junctions, curvilinear strands of connexons were dispersed over 5 to 20 times the area of conventional plaques having equal numbers of connexons. To define morphologies of gap junctions under different light-adaptation conditions, we examined an additional 1150 gap junctions from rats and mice prepared after 30 min of photopic, mesopic and scotopic illumination, with and without general anesthesia. Under these conditions, string and ribbon gap junctions remained abundant in the OFF sublamina and absent in the ON sublamina. Abundant gap junctions in the OFF sublamina of these two rodents with rod-dominant retinas revealed previously-undescribed but extensive pathways for inter-neuronal communication; and the wide dispersion of connexons in string and ribbon gap junctions suggests unique structural features of gap junctional coupling in the OFF vs. ON sublamina. PMID:17010526

Design of multi-modal obstruction to control tonal fan noise using modulation principles

NASA Astrophysics Data System (ADS)

Gérard, Anthony; Moreau, Stéphane; Berry, Alain; Masson, Patrice

2015-11-01

The approach presented in this paper uses a combination of obstructions in the upstream flow of subsonic axial fans with B blades to destructively interfere with the primary tonal noise at the blade passage frequency. The first step of the proposed experimental method consists in identifying the independent radiation of B - 1 and B lobed obstructions at the control microphones. During this identification step, rotating obstructions allow for the frequencies of primary and secondary tonal noise to be slightly shifted in the spectrum due to modulation principles. The magnitude of the secondary tonal noise generated by each obstruction can be adjusted by varying the size of the lobes of the obstruction, and the phase of the secondary tonal noise is related to the angular position of the obstruction. The control obstructions are then optimized by combining the B - 1 and B lobed obstructions to significantly reduce the acoustic power at blade passage frequency.

Bowel obstruction complicated by ischemia: analysis of CT findings.

PubMed

Cox, Veronica L; Tahvildari, Ali M; Johnson, Benjamin; Wei, Wei; Jeffrey, R Brooke

2018-06-01

To analyze CT signs of bowel ischemia in patients with surgical bowel obstruction, and thereby improve CT diagnosis in this common clinical scenario. Surgical and histopathological findings were used as the reference standard. We retrospectively analyzed CT findings in patients brought to surgery for bowel obstruction over 13 years. Etiology of obstruction (adhesion, hernia, etc.) was recorded. Specific CT features of acute mesenteric ischemia (AMI) were analyzed, including bowel wall thickening, mucosal hypoenhancement, and others. 173 cases were eligible for analysis. 21% of cases were positive for bowel ischemia. Volvulus, internal hernia, and closed-loop obstructions showed ischemia rates of 60%, 43%, and 43%; ischemia rate in obstruction from simple adhesion was 21%. Patients with bowel obstruction related to malignancy were never ischemic. Sensitivities and specificities for CT features predicting ischemia were calculated, with wall thickening, hypoenhancement, and pneumatosis showing high specificity for ischemia (86%-100%). Wall thickening, hypoenhancement, and pneumatosis are highly specific CT signs of ischemia in the setting of obstruction. None of the evaluated CT signs were found to be highly sensitive. Overall frequency of ischemia in surgical bowel obstruction is 21%, and 2-3 times that for complex obstructions (volvulus, closed loop, etc.). Obstructions related to malignancy virtually never become ischemic.

Evaluation of two techniques of partial urethral obstruction in the male rat model of bladder outlet obstruction.

PubMed

Melman, Arnold; Tar, Moses; Boczko, Judd; Christ, George; Leung, Albert C; Zhao, Weixin; Russell, Robert G

2005-11-01

To perform a comparison to determine which of two methods of partial urethral ligation produces the most consistent outcome and fewest side effects. Such a study has not been previously reported. Partial urethral ligation is a means of causing reproducible bladder outlet obstruction. In the male rat model, partial urethral obstruction can be performed either by perineal incision and bulbous urethral ligation or retropubic incision and midprostatic obstruction. Fifteen male Sprague-Dawley rats were studied. Five were selected for bulbous urethral obstruction through a perineal incision, five for midprostatic obstruction using a retropubic approach, and five for a sham operation through a perineal incision. The operative time was shorter and morbidity lower with the perineal approach compared with the retropubic approach. Inflammation or infection, or both, were seen in the prostate, bladder, proximal urethra, ureters, and kidneys in the rats in which a midprostatic obstruction was performed. The proximal urethra and prostate were mildly inflamed in those rats that underwent bulbous obstruction. Sham-operated rats exhibited mild prostatitis only. The perineal approach to the bulbous urethra is the method of choice for creating a partial urethral obstruction model of bladder outlet obstruction in the male rat.

Urinary obstruction is an important complicating factor in patients with septic shock due to urinary infection.

PubMed

Reyner, Karina; Heffner, Alan C; Karvetski, Colleen H

2016-04-01

Urinary tract infection (UTI) is a common cause of severe sepsis, and anatomic urologic obstruction is a recognized factor for complicated disease. We aimed to identify the incidence of urinary obstruction complicating acute septic shock and determine the characteristics and outcomes of this group. Patients prospectively enrolled in a sepsis treatment pathway registry between October 2013 and July 2014 were reviewed for the diagnosis of UTI. Standardized medical record review was performed to confirm sepsis due to UTI and determine clinical variables including the presence of anatomic urinary obstruction. Patients with septic shock due to UTI with obstruction were compared with those without obstruction. The primary outcomes were incidence of urinary obstruction and hospital mortality. Among 1084 registry enrollees, 209 (19.2%) met inclusion criteria for the study. Acute anatomic obstruction was identified in 22 (10.5%) patients. Hospital mortality in patients with obstruction was 27.3% compared with 11.2% in patients without obstruction (absolute difference of 16.1%; P = .03; 95% confidence interval [CI], 1.2%-30.9%). Hospital length of stay among survivors was 12.8 days compared with 8.3 days (absolute difference of 4.5 days; P = .04; 95% CI, 0.2-8.8 days). History of urinary stone disease was independently associated with obstruction (odds ratio, 5.6; 95% CI, 2.2-14.3). Approximately 1 in 10 patients presenting with septic shock due to a urinary source is complicated by anatomic urinary obstruction. These patients have significantly higher mortality compared with patients without obstruction. Early imaging of patients with septic shock due to suspected urinary source should be considered to identify obstruction requiring emergency intervention. Copyright © 2015 Elsevier Inc. All rights reserved.

Signaling from the Podocyte Intercellular Junction to the Actin Cytoskeleton

PubMed Central

George, Britta; Holzman, Lawrence B.

2012-01-01

Observations of hereditary glomerular disease support the contention that podocyte intercellular junction proteins are essential for junction formation and maintenance. Genetic deletion of most of these podocyte intercellular junction proteins results in foot process effacement and proteinuria. This review focuses on the current understanding of molecular mechanisms by which podocyte intercellular junction proteins such as the Nephrin-Neph1-Podocin receptor complex coordinate cytoskeletal dynamics and thus intercellular junction formation, maintenance and injury-dependent remodeling. PMID:22958485

Visualizing the effect of dynamin inhibition on annular gap vesicle formation and fission

PubMed Central

Nickel, Beth; Boller, Marie; Schneider, Kimberly; Shakespeare, Teresa; Gay, Vernon; Murray, Sandra A.

2013-01-01

Summary Although gap junction plaque assembly has been extensively studied, mechanisms involved in plaque disassembly are not well understood. Disassembly involves an internalization process in which annular gap junction vesicles are formed. These vesicles undergo fission, but the molecular machinery needed for these fissions has not been described. The mechanoenzyme dynamin has been previously demonstrated to play a role in gap junction plaque internalization. To investigate the role of dynamin in annular gap junction vesicle fission, immunocytochemical, time-lapse and transmission electron microscopy were used to analyze SW-13 adrenocortical cells in culture. Dynamin was demonstrated to colocalize with gap junction plaques and vesicles. Dynamin inhibition, by siRNA knockdown or treatment with the dynamin GTPase inhibitor dynasore, increased the number and size of gap junction ‘buds’ suspended from the gap junction plaques. Buds, in control populations, were frequently released to form annular gap junction vesicles. In dynamin-inhibited populations, the buds were larger and infrequently released and thus fewer annular gap junction vesicles were formed. In addition, the number of annular gap junction vesicle fissions per hour was reduced in the dynamin-inhibited populations. We believe this to be the first report addressing the details of annular gap junction vesicle fissions and demonstrating a role of dynamin in this process. This information is crucial for elucidating the relationship between gap junctions, membrane regulation and cell behavior. PMID:23591819

Role of heteromeric gap junctions in the cytotoxicity of cisplatin.

PubMed

Tong, Xuhui; Dong, Shuying; Yu, Meiling; Wang, Qin; Tao, Liang

2013-08-09

In several systems, the presence of gap junctions made of a single connexin has been shown to enhance the cytotoxicity of cisplatin. However, most gap junction channels in vivo appear to be heteromeric (composed of more than one connexin isoform). Here we explore in HeLa cells the cytotoxicity to cisplatin that is enhanced by heteromeric gap junctions composed of Cx26 and Cx32, which have been shown to be more selective among biological permeants than the corresponding homomeric channels. We found that survival and subsequent proliferation of cells exposed to cisplatin were substantially reduced when gap junctions were present than when there were no gap junctions. Functional inhibition of gap junctions by oleamide enhanced survival/proliferation, and enhancement of gap junctions by retinoic acid decreased survival/proliferation. These effects occurred only in high density cultures, and the treatments were without effect when there was no opportunity for gap junction formation. The presence of functional gap junctions enhanced apoptosis as reflected in markers of both early-stage and late-stage apoptosis. Furthermore, analysis of caspases 3, 8 and 9 showed that functional gap junctions specifically induced apoptosis by the mitochondrial pathway. These results demonstrate that heteromeric Cx26/Cx32 gap junctions increase the cytotoxicity of cisplatin by induction of apoptosis via the mitochondrial pathway. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Visualizing the effect of dynamin inhibition on annular gap vesicle formation and fission.

PubMed

Nickel, Beth; Boller, Marie; Schneider, Kimberly; Shakespeare, Teresa; Gay, Vernon; Murray, Sandra A

2013-06-15

Although gap junction plaque assembly has been extensively studied, mechanisms involved in plaque disassembly are not well understood. Disassembly involves an internalization process in which annular gap junction vesicles are formed. These vesicles undergo fission, but the molecular machinery needed for these fissions has not been described. The mechanoenzyme dynamin has been previously demonstrated to play a role in gap junction plaque internalization. To investigate the role of dynamin in annular gap junction vesicle fission, immunocytochemical, time-lapse and transmission electron microscopy were used to analyze SW-13 adrenocortical cells in culture. Dynamin was demonstrated to colocalize with gap junction plaques and vesicles. Dynamin inhibition, by siRNA knockdown or treatment with the dynamin GTPase inhibitor dynasore, increased the number and size of gap junction 'buds' suspended from the gap junction plaques. Buds, in control populations, were frequently released to form annular gap junction vesicles. In dynamin-inhibited populations, the buds were larger and infrequently released and thus fewer annular gap junction vesicles were formed. In addition, the number of annular gap junction vesicle fissions per hour was reduced in the dynamin-inhibited populations. We believe this to be the first report addressing the details of annular gap junction vesicle fissions and demonstrating a role of dynamin in this process. This information is crucial for elucidating the relationship between gap junctions, membrane regulation and cell behavior.

A WAVE2–Arp2/3 actin nucleator apparatus supports junctional tension at the epithelial zonula adherens

PubMed Central

Verma, Suzie; Han, Siew Ping; Michael, Magdalene; Gomez, Guillermo A.; Yang, Zhe; Teasdale, Rohan D.; Ratheesh, Aparna; Kovacs, Eva M.; Ali, Radiya G.; Yap, Alpha S.

2012-01-01

The epithelial zonula adherens (ZA) is a specialized adhesive junction where actin dynamics and myosin-driven contractility coincide. The junctional cytoskeleton is enriched in myosin II, which generates contractile force to support junctional tension. It is also enriched in dynamic actin filaments, which are replenished by ongoing actin assembly. In this study we sought to pursue the relationship between actin assembly and junctional contractility. We demonstrate that WAVE2–Arp2/3 is a major nucleator of actin assembly at the ZA and likely acts in response to junctional Rac signaling. Furthermore, WAVE2–Arp2/3 is necessary for junctional integrity and contractile tension at the ZA. Maneuvers that disrupt the function of either WAVE2 or Arp2/3 reduced junctional tension and compromised the ability of cells to buffer side-to-side forces acting on the ZA. WAVE2–Arp2/3 disruption depleted junctions of both myosin IIA and IIB, suggesting that dynamic actin assembly may support junctional tension by facilitating the local recruitment of myosin. PMID:23051739

A WAVE2-Arp2/3 actin nucleator apparatus supports junctional tension at the epithelial zonula adherens.

PubMed

Verma, Suzie; Han, Siew Ping; Michael, Magdalene; Gomez, Guillermo A; Yang, Zhe; Teasdale, Rohan D; Ratheesh, Aparna; Kovacs, Eva M; Ali, Radiya G; Yap, Alpha S

2012-12-01

The epithelial zonula adherens (ZA) is a specialized adhesive junction where actin dynamics and myosin-driven contractility coincide. The junctional cytoskeleton is enriched in myosin II, which generates contractile force to support junctional tension. It is also enriched in dynamic actin filaments, which are replenished by ongoing actin assembly. In this study we sought to pursue the relationship between actin assembly and junctional contractility. We demonstrate that WAVE2-Arp2/3 is a major nucleator of actin assembly at the ZA and likely acts in response to junctional Rac signaling. Furthermore, WAVE2-Arp2/3 is necessary for junctional integrity and contractile tension at the ZA. Maneuvers that disrupt the function of either WAVE2 or Arp2/3 reduced junctional tension and compromised the ability of cells to buffer side-to-side forces acting on the ZA. WAVE2-Arp2/3 disruption depleted junctions of both myosin IIA and IIB, suggesting that dynamic actin assembly may support junctional tension by facilitating the local recruitment of myosin.

Pancreatic Calculus Causing Biliary Obstruction: Endoscopic Therapy for a Rare Initial Presentation of Chronic Pancreatitis.

PubMed

Shetty, Anurag J; Pai, C Ganesh; Shetty, Shiran; Balaraju, Girisha

2015-09-01

Biliary obstruction in chronic calcific pancreatitis (CCP) is often caused by inflammatory or fibrotic strictures of the bile duct, carcinoma of head of pancreas or less commonly by compression from pseudocysts. Pancreatic calculi causing ampullary obstruction and leading to obstructive jaundice is extremely rare. The medical records of all patients with CCP or biliary obstruction who underwent endoscopic retrograde cholangiopancreatography (ERCP) over 4 years between 2010-2014 at Kasturba Medical College, Manipal were analyzed. Five patients of CCP with impacted pancreatic calculi at the ampulla demonstrated during ERCP were identified. All 5 presented with biliary obstruction and were incidentally detected to have CCP when evaluated for the same; 3 patients had features of cholangitis. All the patients were managed successfully by endoscopic papillotomy and extraction of pancreatic calculi from the ampulla with resolution of biliary obstruction. Pancreatic calculus causing ampullary obstruction, though very rare, should be considered as a possibility in patients with CCP complicated by biliary obstruction. Endoscopic therapy is affective in the resolution of biliary obstruction in such patients.

Comparison of different morphological parameters with duration of obstruction created experimentally in unilateral upper ureters: an animal model.

PubMed

Panda, Shasanka Shekhar; Bajpai, Minu; Mallick, Saumyaranjan; Sharma, Mehar C

2014-01-01

The objective of the following study is to determine and to compare the different morphological parameters with duration of obstruction created experimentally in unilateral upper ureters of rats. Unilateral upper ureteric obstruction was created in 60 adult Wistar rats that were reversed after predetermined intervals. Rats were sacrificed and ipsilateral kidneys were subjected for analysis of morphological parameters such as renal height, cranio-caudal diameter, antero-posterior diameter, lateral diameter, volume of the pelvis and average cortical thickness: Renal height. Renal height and cranio-caudal diameter of renal pelvis after ipsilateral upper ureteric obstruction started rising as early as 7 days of creating obstruction and were affected earlier than antero-posterior and lateral diameter and also were reversed earlier than other parameters after reversal of obstruction. Renal cortical thickness and volume of the pelvis were affected after prolonged obstruction (> 3 weeks) and were the late parameters to be reversed after reversal of obstruction. Cranio-caudal diameter and renal height were the early morphological parameters to be affected and reversed after reversal of obstruction in experimentally created ipsilateral upper ureteric obstruction.

Post-obstructive pulmonary edema from aspirated nuts.

PubMed

Bashir, Ahsan; Ahmad, Sabina Qureshi; Silverman, Joshua; Concepcion, Emily; Lee, Haesoon

2017-01-01

Post-obstructive pulmonary edema is thought to occur from hemodynamic changes secondary to forced inspiration against the closed airway due to acute or chronic airway obstruction. We report a case of a 13 month-old boy who developed pulmonary edema from aspirated foreign body, nuts. He underwent emergency bronchoscopy to confirm the clinical diagnosis of aspirated nuts in the trachea and nuts were removed endoscopically. His trachea was then intubated and he was mechanically ventilated with oxygen. He developed florid pulmonary edema early in the course with tracheal obstruction and during endoscopic removal of nuts. After removal of obstruction he was ventilated mechanically and pulmonary edema cleared rapidly. Aspirated nuts obstructing trachea can induce obstructive pulmonary edema. Early recognition of foreign body obstruction based on clinical history and its removal resolved pulmonary edema.

Value of gastrografin in adhesive small bowel obstruction after unsuccessful conservative treatment: A prospective evaluation

PubMed Central

Choi, Hok-Kwok; Law, Wai-Lun; Ho, Judy Wai-Chu; Chu, Kin-Wah

2005-01-01

AIM: Gastrografin is a hyperosmolar water-soluble contrast medium. Besides its predictive value for the need for operative treatment, a potential therapeutic role of this agent in adhesive small bowel obstruction has been suggested. This study aimed at evaluating the effectiveness of gastrografin in adhesive small bowel obstruction when conservative treatment failed. METHODS: Patients with adhesive small bowel obstruction were given trial conservative treatment unless there was fear of bowel strangulation. Those responded in the initial 48 h had conservative treatment continued. Patients who showed no improvement in the initial 48 h were given 100 mL of gastrografin through nasogastric tube followed by serial abdominal radiographs. Patients with the contrast appeared in large bowel within 24 h were regarded as having partial obstruction and conservative treatment was continued. Patients in which the contrast failed to reach large bowel within 24 h were considered to have complete obstruction and laparotomy was performed. RESULTS: Two hundred and twelve patients with 245 episodes of adhesive obstruction were included. Fifteen patients were operated on soon after admission due to fear of strangulation. One hundred and eighty-six episodes of obstruction showed improvement in the initial 48 h and conservative treatment was continued. Two patients had subsequent operations because of persistent obstruction. Forty-four episodes of obstruction showed no improvement within 48 h and gastrografin was administered. Seven patients underwent complete obstruction surgery. Partial obstruction was demonstrated in 37 other cases, obstruction resolved subsequently in all of them except one patient who required laparotomy because of persistent obstruction. The overall operative rate in this study was 10%. There was no complication that could be attributed to the use of gastrografin. CONCLUSION: The use of gastrografin in adhesive small bowel obstruction after unsuccessful conservative treatment is safe and reduces the need for surgical intervention. PMID:15968731

Disruption of gap junctions attenuates aminoglycoside-elicited renal tubular cell injury.

PubMed

Yao, Jian; Huang, Tao; Fang, Xin; Chi, Yuan; Zhu, Ying; Wan, Yigang; Matsue, Hiroyuki; Kitamura, Masanori

2010-08-01

Gap junctions play important roles in the regulation of cell phenotype and in determining cell survival after various insults. Here, we investigated the role of gap junctions in aminoglycoside-induced injury to renal tubular cells. Two tubular epithelial cell lines NRK-E52 and LLC-PK1 were compared for gap junction protein expression and function by immunofluorescent staining, Western blot and dye transfer assay. Cell viability after exposure to aminoglycosides was evaluated by WST assay. Gap junctions were modulated by transfection of the gap junction protein, connexin 43 (Cx43), use of Cx43 siRNA and gap junction inhibitors. NRK-E52 cells expressed abundant Cx43 and were functionally coupled by gap junctional intercellular communication (GJIC). Exposure of NRK-E52 cells to aminoglycosides, G418 and hygromycin, increased Cx43 phosphorylation and GJIC. The aminoglycosides also decreased cell viability that was prevented by gap junction inhibitors and Cx43 siRNA. LLC-PK1 cells were gap junction-deficient and resistant to aminoglycoside-induced cytotoxicity. Over-expression of a wild-type Cx43 converted LLC-PK1 cells to a drug-sensitive phenotype. The gap junction inhibitor alpha-glycyrrhetinic acid (alpha-GA) activated Akt in NRK-E52 cells. Inhibition of the Akt pathway enhanced cell toxicity to G418 and abolished the protective effects of alpha-GA. In addition, gentamycin-elicited cytotoxicity in NRK-E52 cells was also significantly attenuated by alpha-GA. Gap junctions contributed to the cytotoxic effects of aminoglycosides. Modulation of gap junctions could be a promising approach for prevention and treatment of aminoglycoside-induced renal tubular cell injury.

Coincidence of features of emitted THz electromagnetic wave power form a single Josephson junction and different current components

NASA Astrophysics Data System (ADS)

Hamdipour, Mohammad

2017-12-01

By applying a voltage to a Josephson junction, the charge in superconducting layers (S-layers) will oscillate. Wavelength of the charge oscillations in S-layers is related to external current in junction, by increasing the external current, the wavelength will decrease which cause in some currents the wavelength be incommensurate with width of junction, so the CVC shows Fiske like steps. External current throwing along junction has some components, resistive, capacitive and superconducting current, beside these currents there is a current in lateral direction of junction, (x direction). On the other hand, the emitted electromagnetic wave power in THz region is related to AC component of electric field in junction, which itself is related to charge density in S-layers, which is related to currents in the system. So we expect that features of variation of current components reflect the features of emitted THz power form junction. Here we study in detail the superconductive current in a long Josephson junction (JJ), the current voltage characteristics (CVC) of junction and emitted THz power from the system. Then we compare the results. Comparing the results we see that there is a good qualitative coincidence in features of emitted THz power and supercurrent in junction.

Endoscopic Resection of Skull Base Teratoma in Klippel-Feil Syndrome through Use of Combined Ultrasonic and Bipolar Diathermy Platforms

PubMed Central

Psaltis, Alkis J.; Williams, Ryan A.; Charville, Gregory W.; Dodd, Robert L.

2017-01-01

Klippel-Feil syndrome (KFS) is associated with numerous craniofacial abnormalities but rarely with skull base tumor formation. We report an unusual and dramatic case of a symptomatic, mature skull base teratoma in an adult patient with KFS, with extension through the basisphenoid to obstruct the nasopharynx. This benign lesion was associated with midline palatal and cerebral defects, most notably pituitary and vertebrobasilar arteriolar duplications. A multidisciplinary workup and a complete endoscopic, transnasal surgical approach between otolaryngology and neurosurgery were undertaken. Out of concern for vascular control of the fibrofatty dense tumor stalk at the skull base and need for complete teratoma resection, we successfully employed a tissue resection tool with combined ultrasonic and bipolar diathermy to the tumor pedicle at the sphenoid/clivus junction. No CSF leak or major hemorrhage was noted using this endonasal approach, and no concerning postoperative sequelae were encountered. The patient continues to do well now 3 years after tumor extirpation, with resolution of all preoperative symptoms and absence of teratoma recurrence. KFS, teratoma biology, endocrine gland duplication, and the complex considerations required for successfully addressing this type of advanced skull base pathology are all reviewed herein. PMID:28133560

Transperitoneal Laparoscopic Approach to the Perinephric Area in Children: Technical Report and Lessons Learned.

PubMed

Mattioli, Girolamo; Avanzini, Stefano; Pio, Luca; Costanzo, Sara; Faticato, Maria Grazia; Montobbio, Giovanni; Disma, Nicola; Buffa, Piero

2015-10-01

This study presents a technical report of a standardized approach to the perinephric area in a series of pediatric patients, demonstrating that whatever renal or suprarenal surgery is planned, this can be approached and accomplished laparoscopically with an identical or very similar port triangulation, thus facilitating the learning curve within the same surgical team. All patients undergoing renal and adrenal gland surgery with a minimally invasive approach in the period from October 2008 to November 2013 were retrospectively reviewed and included in the study. Technical details and clinical outcomes are described. In total, 68 patients matched the inclusion criteria and were therefore retrospectively examined. No major intraoperative complication occurred. Two patients developed recurrent pelvic-ureteric junction obstruction and were managed with double J stent positioning and laparoscopic dismembered pyeloplasty, respectively. Two patients presenting with adrenal mass experienced a moderate bleeding that could be treated conservatively. Thanks to the reproducibility of the procedure and on the grounds of the presented experience, we support the proposal that the transperitoneal laparoscopic approach to the kidney and the adrenal gland could represent a relatively easy and safe way to quickly achieve confidence and skill in the management of related diseases.

Treatments for achalasia in 2017: how to choose among them.

PubMed

Kahrilas, Peter J; Pandolfino, John E

2017-07-01

To review recent advances in achalasia diagnostics and therapeutics. The cardinal feature of achalasia, impaired lower esophageal sphincter (LES) relaxation, can occur in association with varied patterns of esophageal contractility. The Chicago Classification distinguishes among these as follows: without contractility (type I), with panesophageal pressurization (type II), with premature (spastic) distal esophageal contractions (type III), or even with preserved peristalsis [esophagogastric junction (EGJ) outlet obstruction]. Physiological testing also reveals achalasia-like syndromes that also benefit from achalasia therapies. Coincident with this has been the development of peroral endoscopic myotomy (POEM), an endoscopic technique for performing an esophageal myotomy. Hence, the option now exists to either selectively ablate the LES (pneumatic dilation, laparoscopic Heller myotomy, or POEM) or to ablate the sphincter and create a myotomy along some or the entire adjacent smooth muscle esophagus (POEM). Each achalasia syndrome has unique treatment considerations; type II achalasia responds well to all therapies, whereas type III responds best to POEM. Emerging data support the concept that optimal management of achalasia is phenotype-specific, guided by high-resolution manometry, and, in some instance, functional luminal imaging probe studies. This opinion article reviews the varied characteristic and treatment considerations of achalasia syndromes as currently understood.

Clinical application of hysteroscopic hydrotubation for unexplained infertility in the mare.

PubMed

Inoue, Y; Sekiguchi, M

2017-11-07

Therapeutic techniques for oviductal obstruction in the mare are limited. Nonsurgical and retrograde flushing may be an attractive alternative to current treatment methods for oviductal blockage. To evaluate hysteroscopic selective hydrotubation as a treatment option for presumptive equine oviductal blockage. Retrospective case series. A quantity of 10 mL of saline was flushed through the oviducts in 28 standing sedated mares, which had reproductive histories of unexplained subfertility, by inserting a catheter into the uterotubal junction under endoscopic guidance. All mares in the study had been mated through several cycles (2-20 oestrous cycles) by known fertile stallions prior to treatment, with no evidence of conception. The average number of cycles for each mare prior to treatment was 6.5 ± 4.5. Saline was successfully infused into a total of 50 oviducts. Of 28 mares, 26 conceived after the treatment. The average number of cycles for each mare to become pregnant after treatment was 1.8 ± 0.8. Diagnosis of blocked oviducts was presumptive, and pretreatment infertility was used as the control. This study revealed that hysteroscopic hydrotubation using saline improved pregnancy rates in mares in which oviductal blockage was suspected as a cause of unexplained subfertility. © 2017 EVJ Ltd.

A new variant of aberrant left brachiocephalic trunk in mam: case report and literature review.

PubMed

Szpinda, Michał

2005-02-01

Importance is placed on aberrant arteries in the radiological and surgical literature. A normal left brachiocephalic trunk is characteristic for the right aortic arch. However, an aberrant left brachiocephalic trunk arising as the last branch of the aortic arch on the left side has not yet been described in the literature. Described here is a new variant of the retro-oesophageal aberrant left brachiocephalic trunk, occasionally observed in a patient during diagnostic investigation or surgical treatment for steno-obstructive involvement of the carotid district. The triple anomaly of the left aortic arch consisted of: 1. the presence of a hypoplastic left brachiocephalic trunk behind the oesophagus, 2. the absence of a brachiocephalic trunk on the right side and 3. separate origins of the arteries on the right side, with the right common artery preceding the right subclavian artery. In front of the trachea an 8-mm prosthetic PTFE was implanted from the proximal segment of the right subclavian artery to the junction of the left common carotid and left subclavian arteries. The author demonstrates the inadequacy of auxiliary investigations to detect aberrant arteries, which may only be identified precisely intra-operatively.

Simulating transitional hydrodynamics of the cerebrospinal fluid at extreme scale

NASA Astrophysics Data System (ADS)

Jain, Kartik; Roller, Sabine; Mardal, Kent-Andre

Chiari malformation type I is a disorder characterized by the herniation of cerebellar tonsils into the spinal canal through the foramen magnum resulting in obstruction to cerebrospinal fluid (CSF) outflow. The flow of pulsating bidirectional CSF is of acutely complex nature due to the anatomy of the conduit containing it - the subarachnoid space. We report lattice Boltzmann method based direct numerical simulations on patient specific cases with spatial resolution of 24 μm amounting meshes of up to 2 billion cells conducted on 50000 cores of the Hazelhen supercomputer in Stuttgart. The goal is to characterize intricate dynamics of the CSF at resolutions that are of the order of Kolmogorov microscales. Results unfold velocity fluctuations up to ~ 10 KHz , turbulent kinetic energy ~ 2 times of the mean flow energy in Chiari patients whereas the flow remains laminar in a control subject. The fluctuations confine near the cranio-vertebral junction and are commensurate with the extremeness of pathology and the extent of herniation. The results advocate that the manifestation of pathological conditions like Chiari malformation may lead to transitional hydrodynamics of the CSF, and a prudent calibration of numerical approach is necessary to avoid overlook of such phenomena.

Dynamic cervicomedullary cord compression and alterations in cerebrospinal fluid dynamics in children with achondroplasia: review of an 11-year surgical case series.

PubMed

Mukherjee, Debraj; Pressman, Barry D; Krakow, Deborah; Rimoin, David L; Danielpour, Moise

2014-09-01

Achondroplasia may be associated with compression at the cervicomedullary junction. Determining which patients are at greatest risk for neurological complications of cervicomedullary compression can be difficult. In the current study the authors reviewed their records to determine the incidence and clinical significance of dynamic cervicomedullary stenosis and obstruction of CSF flow along with surgical outcomes following posterior fossa decompression. The authors reviewed 34 consecutive cases involving symptomatic children with achondroplasia undergoing cervicomedullary decompression performed by a single surgeon over 11 years. Of these patients, 29 had undergone preoperative dynamic MRI of the cervicomedullary junction with cine (cinema) CSF flow studies; 13 of these patients underwent postoperative dynamic MRI studies. Clinical outcomes included changes in polysomnography, head circumference percentile, and fontanel characteristics. Radiographic outcomes included changes in dynamic spinal cord diameter, improvement in CSF flow at the foramen magnum, and change in the Evans ratio. Patients were predominantly female, with a mean age at presentation of 6.6 years and mean follow-up of 3.7 years (range 1-10 years). All patients had moderate to excellent improvement in postoperative polysomnography, slight decrease in average head circumference percentile (from 46.9th percentile to 45.7th percentile), and no subjective worsening of fontanel characteristics. The Evans ratio decreased by 2%, spinal cord diameter increased an average of 3.1 mm, 5.2 mm, and 0.2 mm in the neutral, flexed, and extended positions, respectively, and CSF flow improved qualitatively in all 3 positions. There were no postoperative infections, CSF leaks, or other major complications. None of the patients undergoing initial foramen magnum decompression performed at our medical center required reoperation. Patients with achondroplasia and symptomatic cervicomedullary compression have increased risk of dynamic stenosis at the foramen magnum evident upon dynamic cine MRI. Operative decompression may be offered with low risk of complications or need for reoperation.

A bridging stent to surgery in patients with esophageal and gastroesophageal junction cancer has a dramatic negative impact on patient survival: A retrospective cohort study through data acquired from a prospectively maintained national database.

PubMed

Kjaer, D W; Nassar, M; Jensen, L S; Svendsen, L B; Mortensen, F V

2017-02-01

This study aimed to assess the impact of esophageal stenting on postoperative complications and survival in patients with obstructing esophageal and gastroesophageal junction (GEJ) cancer. All patients treated without neoadjuvant therapy that had an R0-resection performed for esophageal and GEJ cancer between January 2003 and December 2010 were identified from a prospectively maintained database. Data on stenting, postoperative mortality, morbidity, recurrence-free survival, complications, and length of hospital stay were collected. Kaplan-Meier plots for survival and recurrence-free survival curves were constructed for R0 resected patients. Data were compared between the stent and no-stent group by nonparametric tests. Two hundred seventy three consecutive R0 resected patients with esophageal or GEJ cancer were identified. Of these patients, 63 had a stent as a bridge to surgery. The male/female ratio was 2.64 (198/75) with a median age in the stent group (SG) of 65.1 versus 64.3 in the no stent group (NSG). Patients were comparable with respect to gender, age, smoking, TNM-classification, oncological treatment, hospital stay, tumor location, and histology. The median survival in the SG was 11.6 months compared with 21.3 months for patients treated without a bridging stent (P < 0.001). There were no statistically significant differences in 30-day mortality between the two groups, but NSG patients exhibited a significantly better two-year survival (P = 0.017). The median recurrence-free survival was 9.1 months for the SG compared with 15.2 months for the NSG. The use of a stent as a bridging procedure to surgery in patients treated without neaoadjuvant therapy for an esophageal or GEJ cancer that later underwent R0 resection decreased the two year survival and the recurrence-free survival. © 2016 International Society for Diseases of the Esophagus.

Tolerance of the canine bladder to intraoperative radiation therapy: an experimental study

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

Kinsella, T.J.; Sindelar, W.F.; DeLuca, A.M.

1988-05-01

An experimental study of bladder tolerance to intraoperative radiotherapy (IORT) was designed using a large animal model (adult American Foxhounds, weight 25-30 kg) to access acute and late radiation effects. Dogs were subjected to laparotomy where the bladder was mobilized and IORT was delivered using a 5 cm circular cone through a cystotomy incision with 12 MeV electrons. The bladder trigone including both ureteral orifices and the proximal urethra was irradiated in groups of 3 dogs with doses of 0, 20, 25, 30, 35, and 40 Gy. Dogs were followed clinically with repeat urinalysis, intravenous pyelogram (IVP), and cystometrogram atmore » 1 month and then Q6 months for up to 4 years. One dog from each dose group was sacrificed electively at 1 and 2 years, whereas the other dog is being followed clinically for a minimum of 4 years. Complete autopsies were performed with particular attention to genitourinary and pelvic structures. No clinically detectable acute toxicity resulted from IORT to the bladder. Three of 15 IORT dogs (1 each at 25, 35, and 40 Gy) showed obstruction of a ureteral orifice with 2 dogs dying of renal failure secondary to bilateral hydronephrosis within 1-2 years of treatment. The remaining 12 IORT dogs and 3 control dogs have normal repeat IVP's and renal function with up to 4 years of follow-up. Serial cystometry demonstrates no major loss of bladder contractility or volume. At autopsy, histological changes of mucosal thinning and telangiectasia with submucosal fibrosis were confined to the IORT field and appeared dose-related. However, the bladder epithelium remained intact at all doses. The ureterovesical junction in animals receiving 20 Gy showed mild fibrosis of the lamina propria and moderate chronic inflammation. Above 20 Gy, these histological changes at the U-V junction were more pronounced with gross stenosis in 3 animals as predicted by the IVP.« less

Tunnel junction multiple wavelength light-emitting diodes

DOEpatents

Olson, Jerry M.; Kurtz, Sarah R.

1992-01-01

A multiple wavelength LED having a monolithic cascade cell structure comprising at least two p-n junctions, wherein each of said at least two p-n junctions have substantially different band gaps, and electrical connector means by which said at least two p-n junctions may be collectively energized; and wherein said diode comprises a tunnel junction or interconnect.

Preliminary Evaluation of the Pathomechanisms of Dysphagia After Occipitospinal Fusion: Kinematic Analysis by Videofluoroscopic Swallowing Study.

PubMed

Kaneyama, Shuichi; Sumi, Masatoshi; Takabatake, Masato; Kasahara, Koichi; Kanemura, Aritetsu; Koh, Akihiro; Hirata, Hiroaki

2016-12-01

Kinematic analysis of swallowing function using videofluoroscopic swallowing study (VFSS). The aims of this study were to analyze swallowing process in the patients who underwent occipitospinal fusion (OSF) and elucidate the pathomechanism of dysphagia after OSF. Although several hypotheses about the pathomechanisms of dysphagia after OSF were suggested, there has been little tangible evidence to support these hypotheses since these hypotheses were based on the analysis of static radiogram or CT. Considering that swallowing is a compositive motion of oropharyngeal structures, the etiology of postoperative dysphagia should be investigated through kinematic approaches. Each four patients with or without postoperative dysphagia (group D and N, respectively) participated in this study. For VFSS, all patients were monitored to swallow 5-mL diluted barium solution by fluoroscopy, and then dynamic passing pattern of the barium solution was analyzed. Additionally, O-C2 angle (O-C2A) was measured for the assessment of craniocervical alignment. O-C2A in group D was -7.5 degrees, which was relatively smaller than 10.3 degrees in group N (P = 0.07). In group D, all cases presented smooth medium passing without any obstruction at the upper cervical level regardless of O-C2A, whereas the obstruction to the passage of medium was detected at the apex of mid-lower cervical ocurvature, where the anterior protrusion of mid-lower cervical spine compressed directly the pharyngeal space. In group N, all cases showed smooth passing of medium through the whole process of swallowing. This study presented that postoperative dysphagia did not occur at the upper cervical level even though there was smaller angle of O-C2A and demonstrated the narrowing of the oropharyngeal space towing to direct compression by the anterior protrusion of mid-lower cervical spine was the etiology of dysphagia after OSF. Therefore, surgeon should pay attention to the alignment of mid-cervical spine as well as craniocervical junction during OSF. 4.

Specific Cx43 phosphorylation events regulate gap junction turnover in vivo

PubMed Central

Solan, Joell L.; Lampe, Paul D.

2014-01-01

Gap junctions, composed of proteins from the connexin gene family, are highly dynamic structures that are regulated by kinase-mediated signaling pathways and interactions with other proteins. Phosphorylation of Connexin43 (Cx43) at different sites controls gap junction assembly, gap junction size and gap junction turnover. Here we present a model describing how Akt, mitogen activated protein kinase (MAPK) and src kinase coordinate to regulate rapid turnover of gap junctions. Specifically, Akt phosphorylates Cx43 at S373 eliminating interaction with zona occludens-1 (ZO-1) allowing gap junctions to enlarge. Then MAPK and src phosphorylate Cx43 to initiate turnover. We integrate published data with new data to test and refine this model. Finally, we propose that differential coordination of kinase activation and Cx43 phosphorylation controls the specific routes of disassembly, e.g., annular junction formation or gap junctions can potentially “unzip” and be internalized/endocytosed into the cell that produced each connexin. PMID:24508467

Factors associated with undiagnosed obstructive sleep apnoea among hypertensive patients: A multisite cross-sectional survey study in Taiwan.

PubMed

Hsu, Hsiu-Chin; Chen, Ning-Hung; Ho, Wan Jing; Lin, Mei-Hsiang

2018-05-01

To investigate the distribution and risk factors associated with undiagnosed obstructive sleep apnoea among hypertensive patients. Obstructive sleep Apnoea has been deemed a cardinal risk factor affecting cardiovascular event, and the condition is still frequently overlooked clinically. The lack of advanced diagnosis often causes hypertensive patients with obstructive sleep apnoea to miss opportunities for preventing chronic diseases. A cross-sectional design. A total of 215 hypertensive participants were recruited from the cardiovascular outpatients of medical centre in northern and middle Taiwan. The Chinese version of Pittsburgh Sleep Quality Index, the Chinese version of the Epworth Sleep Scale and a portable sleep monitoring device were used for data collection. Logistic regression analysis was conducted to identify the factors affecting hypertensive patients with obstructive sleep apnoea, and a multinomial logistic regression analysis was used to examine the major influence factors for each obstructive sleep apnoea severity level. 81.9% of the hypertensive participants were found having obstructive sleep apnoea. Concerning to the obstructive sleep apnoea severity, 50.0% of participants had mild obstructive sleep apnoea. After controlling the confounding variables, the supine position (odds ratio, 1.04; 95% CI, 1.01-1.07), SO 2 (odds ratio, 0.58; 95% CI, 0.38-0.89) and oxygen desaturation index (odds ratio, 2.70; 95% CI, 1.18-6.18) were significantly associated with obstructive sleep apnoea. Furthermore, severe obstructive sleep apnoea was significantly correlated with gender (odds ratio, 0.04; 95% CI, 0.00-0.66), excessive daytime sleepiness (odds ratio, 20.27; 95% CI, 1.58-26.97) and oxygen desaturation index (odds ratio, 4.05; 95% CI, 1.86-8.81). Nearly 82% of the hypertensive participants were found having undiagnosed obstructive sleep apnoea, and 80% of them were mild or moderate severity. Oxygen desaturation index, SO 2 and the supine position were found to be major predictors for obstructive sleep apnoea. Remarkably, oxygen desaturation index was the most significant predictor for mild, moderate and severe obstructive sleep apnoea. Healthcare providers should enhance their sensitivities to hypertensive patients at a high risk for obstructive sleep apnoea by actively assessing common obstructive sleep apnoea symptoms and providing strategies to alleviate obstructive sleep apnoea symptoms. © 2018 John Wiley & Sons Ltd.

A systematic review and meta-analysis of randomized trials and prospective studies comparing covered and bare self-expandable metal stents for the treatment of malignant obstruction in the digestive tract.

PubMed

Yang, Zhiping; Wu, Qiong; Wang, Fang; Ye, Xiaofei; Qi, Xingshun; Fan, Daiming

2013-01-01

Self-expandable metal stents (SEMS) are widely used for the palliative treatment of malignant gastrointestinal obstruction. Our aim was to evaluate the evidence comparing covered and bare SEMS in the digestive tract using meta-analytical techniques. A literature search was performed using PubMed, Cochrane Library, and Embase databases for comparative studies assessing the two types of stents. The primary outcomes of interest were stent patency and patient survival; second outcomes included technical success, clinical success, tumor ingrowth, tumor overgrowth, and stent migration. A random-effects model was conducted. Pooled analysis was done separately based on the different segments of the digestive tract. Eleven studies (8 randomized controlled trials and 3 prospective cohort studies) including a total of 1376 patients were identified. Covered SEMS were equivalent to bare SEMS in terms of technical success, clinical success, stent patency (gastroduodenal obstruction: HR =0.87, 95% CI 0.53-1.42; colorectal obstruction: HR =0.89, 95% CI 0.18-4.45; biliary obstruction: HR =0.73, 95% CI 0.41-1.32) and survival rates (esophageal obstruction: HR =1.80, 95% CI 0.73-4.44; gastroduodenal obstruction: HR =0.83, 95% CI 0.55-1.26; biliary obstruction: HR =0.99, 95% CI 0.77-1.28), although bare stents were more prone to tumor ingrowth (esophageal obstruction: RR =0.10, 95% CI 0.01-0.77; gastroduodenal obstruction: RR =0.12, 95% CI 0.03-0.55; colorectal obstruction: RR =0.21, 95% CI 0.06-0.70; biliary obstruction: RR =0.21, 95% CI 0.06-0.69), whereas covered stents had the higher risk of stent migration (gastroduodenal obstruction: RR =5.01, 95% CI 1.53-16.43; colorectal obstruction: RR =11.70, 95% CI 2.84-48.27; biliary obstruction: RR =8.11, 95% CI 1.47-44.76) and tumor overgrowth (biliary obstruction: RR =2.03, 95% CI 1.08-3.78). Both covered and bare SEMS are comparable in efficacy for the palliative treatment of malignant obstruction in the digestive tract. Each type of the stents has its own merit and demerit relatively.

Nanotube junctions

DOEpatents

Crespi, Vincent Henry; Cohen, Marvin Lou; Louie, Steven Gwon; Zettl, Alexander Karlwalte

2004-12-28

The present invention comprises a new nanoscale metal-semiconductor, semiconductor-semiconductor, or metal-metal junction, designed by introducing topological or chemical defects in the atomic structure of the nanotube. Nanotubes comprising adjacent sections having differing electrical properties are described. These nanotubes can be constructed from combinations of carbon, boron, nitrogen and other elements. The nanotube can be designed having different indices on either side of a junction point in a continuous tube so that the electrical properties on either side of the junction vary in a useful fashion. For example, the inventive nanotube may be electrically conducting on one side of a junction and semiconducting on the other side. An example of a semiconductor-metal junction is a Schottky barrier. Alternatively, the nanotube may exhibit different semiconductor properties on either side of the junction. Nanotubes containing heterojunctions, Schottky barriers, and metal-metal junctions are useful for microcircuitry.

Nanotube junctions

DOEpatents

Crespi, Vincent Henry; Cohen, Marvin Lou; Louie, Steven Gwon Sheng; Zettl, Alexander Karlwalter

2003-01-01

The present invention comprises a new nanoscale metal-semiconductor, semiconductor-semiconductor, or metal-metal junction, designed by introducing topological or chemical defects in the atomic structure of the nanotube. Nanotubes comprising adjacent sections having differing electrical properties are described. These nanotubes can be constructed from combinations of carbon, boron, nitrogen and other elements. The nanotube can be designed having different indices on either side of a junction point in a continuous tube so that the electrical properties on either side of the junction vary in a useful fashion. For example, the inventive nanotube may be electrically conducting on one side of a junction and semiconducting on the other side. An example of a semiconductor-metal junction is a Schottky barrier. Alternatively, the nanotube may exhibit different semiconductor properties on either side of the junction. Nanotubes containing heterojunctions, Schottky barriers, and metal-metal junctions are useful for microcircuitry.

Short Ballistic Josephson Coupling in Planar Graphene Junctions with Inhomogeneous Carrier Doping

NASA Astrophysics Data System (ADS)

Park, Jinho; Lee, Jae Hyeong; Lee, Gil-Ho; Takane, Yositake; Imura, Ken-Ichiro; Taniguchi, Takashi; Watanabe, Kenji; Lee, Hu-Jong

2018-02-01

We report on short ballistic (SB) Josephson coupling in junctions embedded in a planar heterostructure of graphene. Ballistic Josephson coupling is confirmed by the Fabry-Perot-type interference of the junction critical current Ic . The product of Ic and the normal-state junction resistance RN , normalized by the zero-temperature gap energy Δ0 of the superconducting electrodes, turns out to be exceptionally large close to 2, an indication of strong Josephson coupling in the SB junction limit. However, Ic shows a temperature dependence that is inconsistent with the conventional short-junction-like behavior based on the standard Kulik-Omel'yanchuk prediction. We argue that this feature stems from the effects of inhomogeneous carrier doping in graphene near the superconducting contacts, although the junction is in fact in the short-junction limit.

Correlation between the graft-host junction of penetrating keratoplasty by anterior segment-optical coherence tomography and the magnitude of postoperative astigmatism.

PubMed

Nassar, Ghada Azab; Arfeen, Shaimaa Abd El Salam

2017-07-01

This study aimed to evaluate the alignment pattern of the graft-host junction after penetrating keratoplasty (PK) by anterior segment-optical coherence tomography (AS-OCT) and to correlate this pattern with the magnitude of postoperative astigmatism. This retrospective observational study was carried out on forty patients who underwent PK from February 2013 to August 2014. AS-OCT was performed, and the graft-host junctions were classified into well-apposed junction, malapposed junction, and equally apposed junction. Mal-apposition is subdivided into gap and protrusion. The correlations between clinical characteristics, wound profiles from the AS-OCT, and the magnitude of postoperative astigmatism by Sirius camera (Costruzione Strumenti Oftalmici [CSO], Florence, Italy (CSO, Sirius), were analyzed. Graft-host junctions from forty patients were analyzed; 18 eyes had well-apposed junctions, ten eyes had malapposed junctions, and 12 had equally apposed junctions. The mean cylinder was -9.44 ± -4.00D in well-apposed group, -13.40 ± -5.01D in malapposed group, and -4.67 ± -0.94D in equally apposed group. Alignment pattern of the graft-host junction correlated significantly with the magnitude of astigmatism (P = 0.034). Preoperative corneal diseases did not have an effect on the magnitude of astigmatism (P = 0.123). The alignment pattern of the graft-host junction by AS-OCT can explain the postoperative astigmatism after PK where it correlates significantly with the magnitude of astigmatism.

Membrane junctions in Xenopus eggs: their distribution suggests a role in calcium regulation.

PubMed

Gardiner, D M; Grey, R D

1983-04-01

We have observed the presence of membrane junctions formed between the plasma membrane and cortical endoplasmic reticulum of mature, unactivated eggs of xenopus laevis. The parallel, paired membranes of the junction are separated by a 10-mn gap within which electron-dense material is present. This material occurs in patches with an average center-to-center distance of approximately 30 nm. These junctions are rare in immature (but fully grown) oocytes (approximately 2 percent of the plasma membrane is associated with junctions) and increase dramatically during progesterone-induced maturation. Junctions in the mature, unactivated egg are two to three times more abundant in the animal hemisphere (25-30 percent of the plasma membrane associated with junction) as compared with the vegetal hemisphere (10-15 percent). Junction density decreases rapidly to values characteristic of immature oocytes in response to egg activation. The plasma membrane-ER junctions of xenopus eggs are strikingly similar in structure to membrane junctions in muscle cells thought to be essential in the triggering of intracellular calcium release from the sarcoplasmic reticulum. In addition, the junctions' distinctive, animal-vegetal polarity of distribution, their dramatic appearance during maturation, and their disapperance during activation are correlated with previously documented patterns of calcium-mediated events in anuran eggs. We discuss several lines of evidence supporting the hypothesis that these junctions in xenopus eggs are sites that transduce extracellular events into intracellular calcium release during fertilization and activation of development.

Ballistic Graphene Josephson Junctions from the Short to the Long Junction Regimes.

PubMed

Borzenets, I V; Amet, F; Ke, C T; Draelos, A W; Wei, M T; Seredinski, A; Watanabe, K; Taniguchi, T; Bomze, Y; Yamamoto, M; Tarucha, S; Finkelstein, G

2016-12-02

We investigate the critical current I_{C} of ballistic Josephson junctions made of encapsulated graphene-boron-nitride heterostructures. We observe a crossover from the short to the long junction regimes as the length of the device increases. In long ballistic junctions, I_{C} is found to scale as ∝exp(-k_{B}T/δE). The extracted energies δE are independent of the carrier density and proportional to the level spacing of the ballistic cavity. As T→0 the critical current of a long (or short) junction saturates at a level determined by the product of δE (or Δ) and the number of the junction's transversal modes.

Single P-N junction tandem photovoltaic device

DOEpatents

Walukiewicz, Wladyslaw [Kensington, CA; Ager, III, Joel W.; Yu, Kin Man [Lafayette, CA

2012-03-06

A single P-N junction solar cell is provided having two depletion regions for charge separation while allowing the electrons and holes to recombine such that the voltages associated with both depletion regions of the solar cell will add together. The single p-n junction solar cell includes an alloy of either InGaN or InAlN formed on one side of the P-N junction with Si formed on the other side in order to produce characteristics of a two junction (2J) tandem solar cell through only a single P-N junction. A single P-N junction solar cell having tandem solar cell characteristics will achieve power conversion efficiencies exceeding 30%.

Single P-N junction tandem photovoltaic device

DOEpatents

Walukiewicz, Wladyslaw [Kensington, CA; Ager, III, Joel W.; Yu, Kin Man [Lafayette, CA

2011-10-18

A single P-N junction solar cell is provided having two depletion regions for charge separation while allowing the electrons and holes to recombine such that the voltages associated with both depletion regions of the solar cell will add together. The single p-n junction solar cell includes an alloy of either InGaN or InAlN formed on one side of the P-N junction with Si formed on the other side in order to produce characteristics of a two junction (2J) tandem solar cell through only a single P-N junction. A single P-N junction solar cell having tandem solar cell characteristics will achieve power conversion efficiencies exceeding 30%.

Tunnel junction multiple wavelength light-emitting diodes

DOEpatents

Olson, J.M.; Kurtz, S.R.

1992-11-24

A multiple wavelength LED having a monolithic cascade cell structure comprising at least two p-n junctions, wherein each of said at least two p-n junctions have substantially different band gaps, and electrical connector means by which said at least two p-n junctions may be collectively energized; and wherein said diode comprises a tunnel junction or interconnect. 5 figs.

Supercurrent and multiple Andreev reflections in micrometer-long ballistic graphene Josephson junctions.

PubMed

Zhu, Mengjian; Ben Shalom, Moshe; Mishchsenko, Artem; Fal'ko, Vladimir; Novoselov, Kostya; Geim, Andre

2018-02-08

Ballistic Josephson junctions are predicted to support a number of exotic physics processess, providing an ideal system to inject the supercurrent in the quantum Hall regime. Herein, we demonstrate electrical transport measurements on ballistic superconductor-graphene-superconductor junctions by contacting graphene to niobium with a junction length up to 1.5 μm. Hexagonal boron nitride encapsulation and one-dimensional edge contacts guarantee high-quality graphene Josephson junctions with a mean free path of several micrometers and record-low contact resistance. Transports in normal states including the observation of Fabry-Pérot oscillations and Sharvin resistance conclusively witness the ballistic propagation in the junctions. The critical current density J C is over one order of magnitude larger than that of the previously reported junctions. Away from the charge neutrality point, the I C R N product (I C is the critical current and R N the normal state resistance of junction) is nearly a constant, independent of carrier density n, which agrees well with the theory for ballistic Josephson junctions. Multiple Andreev reflections up to the third order are observed for the first time by measuring the differential resistance in the micrometer-long ballistic graphene Josephson junctions.

Imaging snake orbits at graphene n -p junctions

NASA Astrophysics Data System (ADS)

Kolasiński, K.; Mreńca-Kolasińska, A.; Szafran, B.

2017-01-01

We consider conductance mapping of the snake orbits confined along the n -p junction defined in graphene by the electrostatic doping in the quantum Hall regime. We explain the periodicity of conductance oscillations at the magnetic field and the Fermi energy scales by the properties of the n -p junction as a conducting channel. We evaluate the conductance maps for a floating gate scanning the surface of the device. In the quantum Hall conditions the currents flow near the edges of the sample and along the n -p junction. The conductance mapping resolves only the n -p junction and not the edges. The conductance oscillations along the junction are found in the maps with periodicity related to the cyclotron orbits of the scattering current. Stronger probe potentials provide support to localized resonances at one of the sides of the junction with current loops that interfere with the n -p junction currents. The interference results in a series of narrow lines parallel to the junction with positions that strongly depend on the magnetic field through the Aharonov-Bohm effect. The consequences of a limited transparency of finite-width n -p junctions are also discussed.

Microscopic hematuria and calculus-related ureteral obstruction.

PubMed

Stewart, D P; Kowalski, R; Wong, P; Krome, R

1990-01-01

The evaluation of patients with ureteral calculi in the emergency department has historically included urinalysis (UA) and intravenous pyelograms (IVP). This retrospective study was done to determine if a statistically significant relationship existed between the degree of calculus-related ureteral obstruction, proven by IVP, and the presence or absence of microscopic hematuria. Urine red blood cells were recorded as less than 3 rbc/hpf (negative) or greater than or equal to 3 rbc/hpf (positive). IVPs were recorded as nonsevere or severe. IVP criteria were based on the presence or absence of extravasation, greater than 2-hour ureteral filling times, and a numerical scoring system of 1 to 4 for ureteral or calyceal dilatation and nephrogenic effect. Eighty-nine men (72%) had non-severe obstructions and 34 (28%) had severe obstructions. Twenty-five women (68%) had nonsevere obstructions and 12 (32%) had severe obstructions. Of the 28 patients with normal UAs, 11 had severe ureteral obstructions and 17 had nonsevere ureteral obstructions. There were no statistically significant differences between the presence or absence of significant microscopic hematuria and the presence or absence of severe ureteral obstruction. Microscopic hematuria is neither sensitive nor specific in determining the degree of calculus-related ureteral obstruction.

Geodynamical simulation of the RRF triple junction

NASA Astrophysics Data System (ADS)

Wang, Z.; Wei, D.; Liu, M.; Shi, Y.; Wang, S.

2017-12-01

Triple junction is the point at which three plate boundaries meet. Three plates at the triple junction form a complex geological tectonics, which is a natural laboratory to study the interactions of plates. This work studies a special triple junction, the oceanic transform fault intersects the collinear ridges with different-spreading rates, which is free of influence of ridge-transform faults and nearby hotspots. First, we build 3-D numerical model of this triple junction used to calculate the stead-state velocity and temperature fields resulting from advective and conductive heat transfer. We discuss in detail the influence of the velocity and temperature fields of the triple junction from viscosity, spreading rate of the ridge. The two sides of the oceanic transform fault are different sensitivities to the two factors. And, the influence of the velocity mainly occurs within 200km of the triple junction. Then, we modify the model by adding a ridge-transform fault to above model and directly use the velocity structure of the Macquarie triple junction. The simulation results show that the temperature at both sides of the oceanic transform fault decreases gradually from the triple junction, but the temperature difference between the two sides is a constant about 200°. And, there is little effect of upwelling velocity away from the triple junction 100km. The model results are compared with observational data. The heat flux and thermal topography along the oceanic transform fault of this model are consistent with the observed data of the Macquarie triple junction. The earthquakes are strike slip distributed along the oceanic transform fault. Their depths are also consistent with the zone of maximum shear stress. This work can help us to understand the interactions of plates of triple junctions and help us with the foundation for the future study of triple junctions.

Disruption of gap junctions attenuates aminoglycoside-elicited renal tubular cell injury

PubMed Central

Yao, Jian; Huang, Tao; Fang, Xin; Chi, Yuan; Zhu, Ying; Wan, Yigang; Matsue, Hiroyuki; Kitamura, Masanori

2010-01-01

BACKGROUND AND PURPOSE Gap junctions play important roles in the regulation of cell phenotype and in determining cell survival after various insults. Here, we investigated the role of gap junctions in aminoglycoside-induced injury to renal tubular cells. EXPERIMENTAL APPROACH Two tubular epithelial cell lines NRK-E52 and LLC-PK1 were compared for gap junction protein expression and function by immunofluorescent staining, Western blot and dye transfer assay. Cell viability after exposure to aminoglycosides was evaluated by WST assay. Gap junctions were modulated by transfection of the gap junction protein, connexin 43 (Cx43), use of Cx43 siRNA and gap junction inhibitors. KEY RESULTS NRK-E52 cells expressed abundant Cx43 and were functionally coupled by gap junctional intercellular communication (GJIC). Exposure of NRK-E52 cells to aminoglycosides, G418 and hygromycin, increased Cx43 phosphorylation and GJIC. The aminoglycosides also decreased cell viability that was prevented by gap junction inhibitors and Cx43 siRNA. LLC-PK1 cells were gap junction-deficient and resistant to aminoglycoside-induced cytotoxicity. Over-expression of a wild-type Cx43 converted LLC-PK1 cells to a drug-sensitive phenotype. The gap junction inhibitor α-glycyrrhetinic acid (α-GA) activated Akt in NRK-E52 cells. Inhibition of the Akt pathway enhanced cell toxicity to G418 and abolished the protective effects of α-GA. In addition, gentamycin-elicited cytotoxicity in NRK-E52 cells was also significantly attenuated by α-GA. CONCLUSION AND IMPLICATIONS Gap junctions contributed to the cytotoxic effects of aminoglycosides. Modulation of gap junctions could be a promising approach for prevention and treatment of aminoglycoside-induced renal tubular cell injury. PMID:20649601

Expression pattern of adhesion molecules in junctional epithelium differs from that in other gingival epithelia.

PubMed

Hatakeyama, S; Yaegashi, T; Oikawa, Y; Fujiwara, H; Mikami, T; Takeda, Y; Satoh, M

2006-08-01

The gingival epithelium is the physiologically important interface between the bacterially colonized gingival sulcus and periodontal soft and mineralized connective tissues, requiring protection from exposure to bacteria and their products. However, of the three epithelia comprising the gingival epithelium, the junctional epithelium has much wider intercellular spaces than the sulcular epithelium and oral gingival epithelium. Hence, the aim of the present study was to characterize the cell adhesion structure in the junctional epithelium compared with the other two epithelia. Gingival epithelia excised at therapeutic flap surgery from patients with periodontitis were examined for expression of adhesion molecules by immunofluorescence. In the oral gingival epithelium and sulcular epithelium, but not in the junctional epithelium, desmoglein 1 and 2 in cell-cell contact sites were more abundant in the upper than the suprabasal layers. E-cadherin, the main transmembranous molecule of adherens junctions, was present in spinous layers of the oral gingival epithelium and sulcular epithelium, but was scarce in the junctional epithelium. In contrast, desmoglein 3 and P-cadherin were present in all layers of the junctional epithelium as well as the oral gingival epithelium and sulcular epithelium. Connexin 43 was clearly localized to spinous layers of the oral gingival epithelium, sulcular epithelium and parts of the junctional epithelium. Claudin-1 and occludin were expressed in the cell membranes of a few superficial layers of the oral gingival epithelium. These findings indicated that the junctional epithelium contains only a few desmosomes, composed of only desmoglein 3; adherens junctions are probably absent because of defective E-cadherin. Thus, the anchoring junctions connecting junctional epithelium cells are lax, causing widened intercellular spaces. In contrast, the oral gingival epithelium, which has a few tight junctions, functions as a barrier.

Endoplasmic reticulum-plasma membrane junctions: structure, function and dynamics.

PubMed

Okeke, Emmanuel; Dingsdale, Hayley; Parker, Tony; Voronina, Svetlana; Tepikin, Alexei V

2016-06-01

Endoplasmic reticulum (ER)-plasma membrane (PM) junctions are contact sites between the ER and the PM; the distance between the two organelles in the junctions is below 40 nm and the membranes are connected by protein tethers. A number of molecular tools and technical approaches have been recently developed to visualise, modify and characterise properties of ER-PM junctions. The junctions serve as the platforms for lipid exchange between the organelles and for cell signalling, notably Ca(2+) and cAMP signalling. Vice versa, signalling events regulate the development and properties of the junctions. Two Ca(2+) -dependent mechanisms of de novo formation of ER-PM junctions have been recently described and characterised. The junction-forming proteins and lipids are currently the focus of vigorous investigation. Junctions can be relatively short-lived and simple structures, forming and dissolving on the time scale of a few minutes. However, complex, sophisticated and multifunctional ER-PM junctions, capable of attracting numerous protein residents and other cellular organelles, have been described in some cell types. The road from simplicity to complexity, i.e. the transformation from simple 'nascent' ER-PM junctions to advanced stable multiorganellar complexes, is likely to become an attractive research avenue for current and future junctologists. Another area of considerable research interest is the downstream cellular processes that can be activated by specific local signalling events in the ER-PM junctions. Studies of the cell physiology and indeed pathophysiology of ER-PM junctions have already produced some surprising discoveries, likely to expand with advances in our understanding of these remarkable organellar contact sites. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

Within-breath respiratory impedance and airway obstruction in patients with chronic obstructive pulmonary disease.

PubMed

Silva, Karla Kristine Dames da; Faria, Alvaro Camilo Dias; Lopes, Agnaldo José; Melo, Pedro Lopes de

2015-07-01

Recent work has suggested that within-breath respiratory impedance measurements performed using the forced oscillation technique may help to noninvasively evaluate respiratory mechanics. We investigated the influence of airway obstruction on the within-breath forced oscillation technique in smokers and chronic obstructive pulmonary disease patients and evaluated the contribution of this analysis to the diagnosis of chronic obstructive pulmonary disease. Twenty healthy individuals and 20 smokers were assessed. The study also included 74 patients with stable chronic obstructive pulmonary disease. We evaluated the mean respiratory impedance (Zm) as well as values for the inspiration (Zi) and expiration cycles (Ze) at the beginning of inspiration (Zbi) and expiration (Zbe), respectively. The peak-to-peak impedance (Zpp=Zbe-Zbi) and the respiratory cycle dependence (ΔZrs=Ze-Zi) were also analyzed. The diagnostic utility was evaluated by investigating the sensitivity, the specificity and the area under the receiver operating characteristic curve. ClinicalTrials.gov: NCT01888705. Airway obstruction increased the within-breath respiratory impedance parameters that were significantly correlated with the spirometric indices of airway obstruction (R=-0.65, p<0.0001). In contrast to the control subjects and the smokers, the chronic obstructive pulmonary disease patients presented significant expiratory-inspiratory differences (p<0.002). The adverse effects of moderate airway obstruction were detected based on the Zpp with an accuracy of 83%. Additionally, abnormal effects in severe and very severe patients were detected based on the Zm, Zi, Ze, Zbe, Zpp and ΔZrs with a high degree of accuracy (>90%). We conclude the following: (1) chronic obstructive pulmonary disease introduces higher respiratory cycle dependence, (2) this increase is proportional to airway obstruction, and (3) the within-breath forced oscillation technique may provide novel parameters that facilitate the diagnosis of respiratory abnormalities in chronic obstructive pulmonary disease.

[Correlation between obstructive apnea syndrome and difficult airway in ENT surgery].

PubMed

Pera, Marcia Hiray; Tardelli, Maria Angela; Novo, Neil Ferreira; Juliano, Yara; Silva, Helga Cristina Almeida da

2017-12-21

ENT patients with obstructive sleep apnea syndrome have a tendency of collapsing the upper airways in addition to anatomical obstacles. Obstructive sleep apnea syndrome is related to the increased risk of difficult airway and also increased perioperative complications. In order to identify these patients in the preoperative period, the STOP Bang questionnaire has been highlighted because it is summarized and easy to apply. Evaluate through the STOP Bang questionnaire whether patients undergoing ENT surgery with a diagnosis of obstructive sleep apnea syndrome have a higher risk of complications, particularly the occurrence of difficult airway. Measurements of anatomical parameters for difficult airway and questionnaire application for clinical prediction of obstructive sleep apnea syndrome were performed in 48 patients with a previous polysomnographic study. The sample detected difficult airway in about 18.7% of patients, all of them with obstructive sleep apnea syndrome. This group had older age, cervical circumference > 40cm, ASA II and Cormack III/IV. Patients with obstructive sleep apnea syndrome had higher body mass index, cervical circumference, and frequent apnea. In subgroup analysis, the group with severe obstructive sleep apnea syndrome showed a significantly higher SB score compared to patients without this syndrome or with a mild/moderate obstructive sleep apnea syndrome. The STOP Bang questionnaire was not able to predict difficult airway and mild obstructive sleep apnea syndrome, but it identified marked obstructive sleep apnea syndrome. All patients with difficult airway had moderate and marked obstructive sleep apnea syndrome, although this syndrome did not involve difficult airway. The variables Cormack III/IV and BMI greater than 35 Kg.m -2 were able to predict difficult airway and obstructive sleep apnea syndrome, respectively. Copyright © 2017 Sociedade Brasileira de Anestesiologia. Publicado por Elsevier Editora Ltda. All rights reserved.

Greater effect of stroke thrombolysis in the presence of arterial obstruction.

PubMed

De Silva, Deidre A; Churilov, Leonid; Olivot, Jean-Marc; Christensen, Soren; Lansberg, Maarten G; Mlynash, Michael; Campbell, Bruce C V; Desmond, Patricia; Straka, Matus; Bammer, Roland; Albers, Gregory W; Davis, Stephen M; Donnan, Geoffrey A

2011-10-01

Recanalization of arterial obstruction is associated with improved clinical outcomes. There are no controlled data demonstrating whether arterial obstruction status predicts the treatment effect of intravenous (IV) tissue plasminogen activator (tPA). We aimed to determine if the presence of arterial obstruction improves the treatment effect of IV tPA over placebo in attenuating infarct growth. We analyzed 175 ischemic stroke patients treated in the 3-6 hour time window from the Echoplanar Imaging Thrombolytic Evaluation Trial (EPITHET) trial (randomized to IV tPA or placebo) and Diffusion and perfusion imaging Evaluation For Understanding Stroke Evolution (DEFUSE) study (all treated with IV tPA). Infarct growth was calculated as the difference between baseline diffusion-weighted imaging (DWI) and final T2 lesion volumes. Baseline arterial obstruction of large intracranial arteries was graded on magnetic resonance angiography (MRA). Among the 116 patients with adequate baseline MRA and final lesion assessment, 72 had arterial obstruction (48 tPA, 24 placebo) and 44 no arterial obstruction (33 tPA, 11 placebo). Infarct growth was lower in the tPA than placebo group (median difference 26ml, 95% confidence interval [CI], 1-50) in patients with arterial obstruction, but was similar in patients with no arterial obstruction (median difference 5ml, 95%CI, -3 to 9). Infarct growth attenuation with tPA over placebo treatment was greater among patients with arterial obstruction than those without arterial obstruction by a median of 32ml (95%CI, 21-43, p < 0.001). The treatment effect of IV tPA over placebo was greater with baseline arterial obstruction, supporting arterial obstruction status as a consideration in selecting patients more likely to benefit from IV thrombolysis. Copyright © 2011 American Neurological Association.

Gallbladder Polyp Mimicking an Obstructive Calculus

PubMed Central

Bass, James; Fegelman, Ronald H.

1978-01-01

The second documented case of obstructing polyp of the gallbladder—an extremely rare lesion—is presented. Symptoms were indistinguishable from those of acute obstructive cholecystitis. The mechanism of obstruction is hypothesized. ImagesFigure 1 PMID:702555

Ferromagnetic Josephson Junctions for Cryogenic Memory

NASA Astrophysics Data System (ADS)

Niedzielski, Bethany M.; Gingrich, Eric C.; Khasawneh, Mazin A.; Loloee, Reza; Pratt, William P., Jr.; Birge, Norman O.

2015-03-01

Josephson junctions containing ferromagnetic materials are of interest for both scientific and technological purposes. In principle, either the amplitude of the critical current or superconducting phase shift across the junction can be controlled by the relative magnetization directions of the ferromagnetic layers in the junction. Our approach concentrates on phase control utilizing two junctions in a SQUID geometry. We will report on efforts to control the phase of junctions carrying either spin-singlet or spin-triplet supercurrent for cryogenic memory applications. Supported by Northorp Grumman Corporation and by IARPA under SPAWAR Contract N66001-12-C-2017.

Calcium/Ask1/MKK7/JNK2/c-Src signalling cascade mediates disruption of intestinal epithelial tight junctions by dextran sulfate sodium.

PubMed

Samak, Geetha; Chaudhry, Kamaljit K; Gangwar, Ruchika; Narayanan, Damodaran; Jaggar, Jonathan H; Rao, RadhaKrishna

2015-02-01

Disruption of intestinal epithelial tight junctions is an important event in the pathogenesis of ulcerative colitis. Dextran sodium sulfate (DSS) induces colitis in mice with symptoms similar to ulcerative colitis. However, the mechanism of DSS-induced colitis is unknown. We investigated the mechanism of DSS-induced disruption of intestinal epithelial tight junctions and barrier dysfunction in Caco-2 cell monolayers in vitro and mouse colon in vivo. DSS treatment resulted in disruption of tight junctions, adherens junctions and actin cytoskeleton leading to barrier dysfunction in Caco-2 cell monolayers. DSS induced a rapid activation of c-Jun N-terminal kinase (JNK), and the inhibition or knockdown of JNK2 attenuated DSS-induced tight junction disruption and barrier dysfunction. In mice, DSS administration for 4 days caused redistribution of tight junction and adherens junction proteins from the epithelial junctions, which was blocked by JNK inhibitor. In Caco-2 cell monolayers, DSS increased intracellular Ca(2+) concentration, and depletion of intracellular Ca(2+) by 1,2-bis-(o-aminophenoxy)ethane-N,N,N',N'-tetra-acetic acid tetrakis(acetoxymethyl ester) (BAPTA/AM) or thapsigargin attenuated DSS-induced JNK activation, tight junction disruption and barrier dysfunction. Knockdown of apoptosis signal-regulated kinase 1 (Ask1) or MKK7 blocked DSS-induced tight junction disruption and barrier dysfunction. DSS activated c-Src by a Ca2+ and JNK-dependent mechanism. Inhibition of Src kinase activity or knockdown of c-Src blocked DSS-induced tight junction disruption and barrier dysfunction. DSS increased tyrosine phosphorylation of occludin, zonula occludens-1 (ZO-1), E-cadherin and β-catenin. SP600125 abrogated DSS-induced tyrosine phosphorylation of junctional proteins. Recombinant JNK2 induced threonine phosphorylation and auto-phosphorylation of c-Src. The present study demonstrates that Ca(2+)/Ask1/MKK7/JNK2/cSrc signalling cascade mediates DSS-induced tight junction disruption and barrier dysfunction.

Fluorescence recovery after photobleaching reveals regulation and distribution of connexin36 gap junction coupling within mouse islets of Langerhans

PubMed Central

Farnsworth, Nikki L; Hemmati, Alireza; Pozzoli, Marina; Benninger, Richard K P

2014-01-01

The pancreatic islets are central to the maintenance of glucose homeostasis through insulin secretion. Glucose-stimulated insulin secretion is tightly linked to electrical activity in β cells within the islet. Gap junctions, composed of connexin36 (Cx36), form intercellular channels between β cells, synchronizing electrical activity and insulin secretion. Loss of gap junction coupling leads to altered insulin secretion dynamics and disrupted glucose homeostasis. Gap junction coupling is known to be disrupted in mouse models of pre-diabetes. Although approaches to measure gap junction coupling have been devised, they either lack cell specificity, suitable quantification of coupling or spatial resolution, or are invasive. The purpose of this study was to develop fluorescence recovery after photobleaching (FRAP) as a technique to accurately and robustly measure gap junction coupling in the islet. The cationic dye Rhodamine 123 was used with FRAP to quantify dye diffusion between islet β cells as a measure of Cx36 gap junction coupling. Measurements in islets with reduced Cx36 verified the accuracy of this technique in distinguishing between distinct levels of gap junction coupling. Analysis of individual cells revealed that the distribution of coupling across the islet is highly heterogeneous. Analysis of several modulators of gap junction coupling revealed glucose- and cAMP-dependent modulation of gap junction coupling in islets. Finally, FRAP was used to determine cell population specific coupling, where no functional gap junction coupling was observed between α cells and β cells in the islet. The results of this study show FRAP to be a robust technique which provides the cellular resolution to quantify the distribution and regulation of Cx36 gap junction coupling in specific cell populations within the islet. Future studies utilizing this technique may elucidate the role of gap junction coupling in the progression of diabetes and identify mechanisms of gap junction regulation for potential therapies. PMID:25172942

Fluorescence recovery after photobleaching reveals regulation and distribution of connexin36 gap junction coupling within mouse islets of Langerhans.

PubMed

Farnsworth, Nikki L; Hemmati, Alireza; Pozzoli, Marina; Benninger, Richard K P

2014-10-15

The pancreatic islets are central to the maintenance of glucose homeostasis through insulin secretion. Glucose‐stimulated insulin secretion is tightly linked to electrical activity in β cells within the islet. Gap junctions, composed of connexin36 (Cx36), form intercellular channels between β cells, synchronizing electrical activity and insulin secretion. Loss of gap junction coupling leads to altered insulin secretion dynamics and disrupted glucose homeostasis. Gap junction coupling is known to be disrupted in mouse models of pre‐diabetes. Although approaches to measure gap junction coupling have been devised, they either lack cell specificity, suitable quantification of coupling or spatial resolution, or are invasive. The purpose of this study was to develop fluorescence recovery after photobleaching (FRAP) as a technique to accurately and robustly measure gap junction coupling in the islet. The cationic dye Rhodamine 123 was used with FRAP to quantify dye diffusion between islet β cells as a measure of Cx36 gap junction coupling. Measurements in islets with reduced Cx36 verified the accuracy of this technique in distinguishing between distinct levels of gap junction coupling. Analysis of individual cells revealed that the distribution of coupling across the islet is highly heterogeneous. Analysis of several modulators of gap junction coupling revealed glucose‐ and cAMP‐dependent modulation of gap junction coupling in islets. Finally, FRAP was used to determine cell population specific coupling, where no functional gap junction coupling was observed between α cells and β cells in the islet. The results of this study show FRAP to be a robust technique which provides the cellular resolution to quantify the distribution and regulation of Cx36 gap junction coupling in specific cell populations within the islet. Future studies utilizing this technique may elucidate the role of gap junction coupling in the progression of diabetes and identify mechanisms of gap junction regulation for potential therapies.

Long-term survival and causes of death in patients with ST-elevation acute coronary syndrome without obstructive coronary artery disease.

PubMed

Andersson, Hedvig Bille; Pedersen, Frants; Engstrøm, Thomas; Helqvist, Steffen; Jensen, Morten Kvistholm; Jørgensen, Erik; Kelbæk, Henning; Räder, Sune Bernd Emil Werner; Saunamäki, Kari; Bates, Eric; Grande, Peer; Holmvang, Lene; Clemmensen, Peter

2018-01-07

We aimed to study survival and causes of death in patients with ST-elevation acute coronary syndrome (STE-ACS) with and without obstructive coronary artery disease (CAD). We included 4793 consecutive patients with STE-ACS triaged for acute coronary angiography at a large cardiac invasive centre (2009-2014). Of these, 88% had obstructive CAD (stenosis ≥50%), 6% had non-obstructive CAD (stenosis 1-49%), and 5% had normal coronary arteries. Patients without obstructive CAD were younger and more often female with fewer cardiovascular risk factors. Median follow-up time was 2.6 years. Compared with patients with obstructive CAD, the short-term hazard of death (≤30 days) was lower in both patients with non-obstructive CAD [hazard ratio (HR) 0.49, 95% confidence interval (CI) 0.27-0.89, P = 0.018] and normal coronary arteries (HR 0.31, 95% CI 0.11-0.83, P = 0.021). In contrast, the long-term hazard of death (>30 days) was similar in patients with non-obstructive CAD (HR 1.15, 95% CI 0.77-1.72, P = 0.487) and higher in patients with normal coronary arteries (HR 2.44, 95% CI 1.58-3.76, P < 0.001), regardless of troponin levels. Causes of death were cardiovascular in 70% of patients with obstructive CAD, 38% with non-obstructive CAD, and 32% with normal coronary arteries. Finally, patients without obstructive CAD had lower survival compared with an age and sex matched general population. STE-ACS patients without obstructive CAD had a long-term risk of death similar to or higher than patients with obstructive CAD. Causes of death were less often cardiovascular. This suggests that STE-ACS patients without obstructive CAD warrant medical attention and close follow-up. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.

Calcium Channels and Oxidative Stress Mediate a Synergistic Disruption of Tight Junctions by Ethanol and Acetaldehyde in Caco-2 Cell Monolayers.

PubMed

Samak, Geetha; Gangwar, Ruchika; Meena, Avtar S; Rao, Roshan G; Shukla, Pradeep K; Manda, Bhargavi; Narayanan, Damodaran; Jaggar, Jonathan H; Rao, RadhaKrishna

2016-12-13

Ethanol is metabolized into acetaldehyde in most tissues. In this study, we investigated the synergistic effect of ethanol and acetaldehyde on the tight junction integrity in Caco-2 cell monolayers. Expression of alcohol dehydrogenase sensitized Caco-2 cells to ethanol-induced tight junction disruption and barrier dysfunction, whereas aldehyde dehydrogenase attenuated acetaldehyde-induced tight junction disruption. Ethanol up to 150 mM did not affect tight junction integrity or barrier function, but it dose-dependently increased acetaldehyde-mediated tight junction disruption and barrier dysfunction. Src kinase and MLCK inhibitors blocked this synergistic effect of ethanol and acetaldehyde on tight junction. Ethanol and acetaldehyde caused a rapid and synergistic elevation of intracellular calcium. Calcium depletion by BAPTA or Ca 2+ -free medium blocked ethanol and acetaldehyde-induced barrier dysfunction and tight junction disruption. Diltiazem and selective knockdown of TRPV6 or Ca V 1.3 channels, by shRNA blocked ethanol and acetaldehyde-induced tight junction disruption and barrier dysfunction. Ethanol and acetaldehyde induced a rapid and synergistic increase in reactive oxygen species by a calcium-dependent mechanism. N-acetyl-L-cysteine and cyclosporine A, blocked ethanol and acetaldehyde-induced barrier dysfunction and tight junction disruption. These results demonstrate that ethanol and acetaldehyde synergistically disrupt tight junctions by a mechanism involving calcium, oxidative stress, Src kinase and MLCK.

Assembly of the Escherichia coli RuvABC resolvasome directs the orientation of Holliday junction resolution

PubMed Central

van Gool, Alain J.; Hajibagheri, Nasser M.A.; Stasiak, Andrzej; West, Stephen C.

1999-01-01

Genetic recombination can lead to the formation of intermediates in which DNA molecules are linked by Holliday junctions. Movement of a junction along DNA, by a process known as branch migration, leads to heteroduplex formation, whereas resolution of a junction completes the recombination process. Holliday junctions can be resolved in either of two ways, yielding products in which there has, or has not, been an exchange of flanking markers. The ratio of these products is thought to be determined by the frequency with which the two isomeric forms (conformers) of the Holliday junction are cleaved. Recent studies with enzymes that process Holliday junctions in Escherichia coli, the RuvABC proteins, however, indicate that protein binding causes the junction to adopt an open square-planar configuration. Within such a structure, DNA isomerization can have little role in determining the orientation of resolution. To determine the role that junction-specific protein assembly has in determining resolution bias, a defined in vitro system was developed in which we were able to direct the assembly of the RuvABC resolvasome. We found that the bias toward resolution in one orientation or the other was determined simply by the way in which the Ruv proteins were positioned on the junction. Additionally, we provide evidence that supports current models on RuvABC action in which Holliday junction resolution occurs as the resolvasome promotes branch migration. PMID:10421637

Models and methods for in vitro testing of hepatic gap junctional communication.

PubMed

Maes, Michaël; Yanguas, Sara Crespo; Willebrords, Joost; Vinken, Mathieu

2015-12-25

Inherent to their pivotal roles in controlling all aspects of the liver cell life cycle, hepatocellular gap junctions are frequently disrupted upon impairment of the homeostatic balance, as occurs during liver toxicity. Hepatic gap junctions, which are mainly built up by connexin32, are specifically targeted by tumor promoters and epigenetic carcinogens. This renders inhibition of gap junction functionality a suitable indicator for the in vitro detection of nongenotoxic hepatocarcinogenicity. The establishment of a reliable liver gap junction inhibition assay for routine in vitro testing purposes requires a cellular system in which gap junctions are expressed at an in vivo-like level as well as an appropriate technique to probe gap junction activity. Both these models and methods are discussed in the current paper, thereby focusing on connexin32-based gap junctions. Copyright © 2015 Elsevier B.V. All rights reserved.

Effect of inductive and capacitive coupling on the current–voltage characteristic and electromagnetic radiation from a system of Josephson junctions

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

Rahmonov, I. R., E-mail: rahmonov@theor.jinr.ru, E-mail: ilhom-tj@inbox.ru; Shukrinov, Yu. M.; Atanasova, P. Kh.

We have studied the current–voltage characteristic of a system of long Josephson junctions taking into account the inductive and capacitive coupling. The dependence of the average time derivative of the phase difference on the bias current and spatiotemporal dependences of the phase difference and magnetic field in each junction are considered. The possibility of branching of the current–voltage characteristic in the region of zero field step, which is associated with different numbers of fluxons in individual Josephson junctions, is demonstrated. The current–voltage characteristic of the system of Josephson junctions is compared with the case of a single junction, and itmore » is shown that the observed branching is due to coupling between the junctions. The intensity of electromagnetic radiation associated with motion of fluxons is calculated, and the effect of coupling between junctions on the radiation power is analyzed.« less

Varactor with integrated micro-discharge source

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

Elizondo-Decanini, Juan M.; Manginell, Ronald P.; Moorman, Matthew W.

2016-10-18

An apparatus that includes a varactor element and an integrated micro-discharge source is disclosed herein. In a general embodiment, the apparatus includes at least one np junction and at least one voltage source that is configured to apply voltage across the np junction. The apparatus further includes an aperture that extends through the np junction. When the voltage is applied across the np junction, gas in the aperture is ionized, forming a plasma, in turn causing a micro-discharge (of light, charge particles, and space charge) to occur. The light (charge particles, and space charge) impinges upon the surface of themore » np junction exposed in the aperture, thereby altering capacitance of the np junction. When used within an oscillator circuit, the effect of the plasma on the np-junction extends the capacitance changes of the np-junction and extends the oscillator frequency range in ways not possible by a conventional voltage controlled oscillator (VCO).« less

Extension of the ADC Charge-Collection Model to Include Multiple Junctions

NASA Technical Reports Server (NTRS)

Edmonds, Larry D.

2011-01-01

The ADC model is a charge-collection model derived for simple p-n junction silicon diodes having a single reverse-biased p-n junction at one end and an ideal substrate contact at the other end. The present paper extends the model to include multiple junctions, and the goal is to estimate how collected charge is shared by the different junctions.

Acute Duodenal Obstruction After Percutaneous Placement of Metallic Biliary Stents: Peroral Treatment with Enteral Stents

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

Lopera, Jorge E.; Alvarez, Oscar A.; Perdigao, Joseph

2003-09-15

Three patients with malignant biliary obstruction were treated with placement of metallic biliary stents. Two patients had known partial duodenal stenosis but had no symptoms of gastrointestinal obstruction. The patients developed symptomatic duodenal obstruction early after biliary metallic stent placement. The symptomatic duodenal obstructions were successfully treated with peroral placement of duodenal stents, which obviated the need for surgical intervention.

Cell-specific expression of connexins and evidence of restricted gap junctional coupling between glial cells and between neurons.

PubMed

Rash, J E; Yasumura, T; Dudek, F E; Nagy, J I

2001-03-15

The transmembrane connexin proteins of gap junctions link extracellularly to form channels for cell-to-cell exchange of ions and small molecules. Two primary hypotheses of gap junction coupling in the CNS are the following: (1) generalized coupling occurs between neurons and glia, with some connexins expressed in both neurons and glia, and (2) intercellular junctional coupling is restricted to specific coupling partners, with different connexins expressed in each cell type. There is consensus that gap junctions link neurons to neurons and astrocytes to oligodendrocytes, ependymocytes, and other astrocytes. However, unresolved are the existence and degree to which gap junctions occur between oligodendrocytes, between oligodendrocytes and neurons, and between astrocytes and neurons. Using light microscopic immunocytochemistry and freeze-fracture replica immunogold labeling of adult rat CNS, we investigated whether four of the best-characterized CNS connexins are each present in one or more cell types, whether oligodendrocytes also share gap junctions with other oligodendrocytes or with neurons, and whether astrocytes share gap junctions with neurons. Connexin32 (Cx32) was found only in gap junctions of oligodendrocyte plasma membranes, Cx30 and Cx43 were found only in astrocyte membranes, and Cx36 was only in neurons. Oligodendrocytes shared intercellular gap junctions only with astrocytes, with each oligodendrocyte isolated from other oligodendrocytes except via astrocyte intermediaries. Finally, neurons shared gap junctions only with other neurons and not with glial cells. Thus, the different cell types of the CNS express different connexins, which define separate pathways for neuronal versus glial gap junctional communication.

Regulation of Gap Junction Dynamics by UNC-44/ankyrin and UNC-33/CRMP through VAB-8 in C. elegans Neurons

PubMed Central

Yan, Dong

2016-01-01

Gap junctions are present in both vertebrates and invertebrates from nematodes to mammals. Although the importance of gap junctions has been documented in many biological processes, the molecular mechanisms underlying gap junction dynamics remain unclear. Here, using the C. elegans PLM neurons as a model, we show that UNC-44/ankyrin acts upstream of UNC-33/CRMP in regulation of a potential kinesin VAB-8 to control gap junction dynamics, and loss-of-function in the UNC-44/UNC-33/VAB-8 pathway suppresses the turnover of gap junction channels. Therefore, we first show a signal pathway including ankyrin, CRMP, and kinesin in regulating gap junctions. PMID:27015090

Many-junction photovoltaic device performance under non-uniform high-concentration illumination

NASA Astrophysics Data System (ADS)

Valdivia, Christopher E.; Wilkins, Matthew M.; Chahal, Sanmeet S.; Proulx, Francine; Provost, Philippe-Olivier; Masson, Denis P.; Fafard, Simon; Hinzer, Karin

2017-09-01

A parameterized 3D distributed circuit model was developed to calculate the performance of III-V solar cells and photonic power converters (PPC) with a variable number of epitaxial vertically-stacked pn junctions. PPC devices are designed with many pn junctions to realize higher voltages and to operate under non-uniform illumination profiles from a laser or LED. Performance impacts of non-uniform illumination were greatly reduced with increasing number of junctions, with simulations comparing PPC devices with 3 to 20 junctions. Experimental results using Azastra Opto's 12- and 20-junction PPC illuminated by an 845 nm diode laser show high performance even with a small gap between the PPC and optical fiber output, until the local tunnel junction limit is reached.

Mechanically Stacked Dual-Junction and Triple-Junction III-V/Si-IBC Cells with Efficiencies Exceeding 31.5% and 35.4%: Preprint

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

Schnabel, Manuel; Tamboli, Adele C; Warren, Emily L

Despite steady advancements in the efficiency of crystalline Silicon (c-Si) photovoltaics (PV) within the last decades, the theoretical efficiency limit of 29.4 percent depicts an insurmountable barrier for silicon-based single-junction solar cells. Combining the Si cell with a second absorber material on top in a dual junction tandem or triple junction solar cell is an attractive option to surpass this limit significantly. We demonstrate a mechanically stacked GaInP/Si dual-junction cell with an in-house measured efficiency of 31.5 percent and a GaInP/GaAs/Si triple-junction cell with a certified efficiency of 35.4 percent.

Controlling formation of single-molecule junctions by electrochemical reduction of diazonium terminal groups.

PubMed

Hines, Thomas; Díez-Pérez, Ismael; Nakamura, Hisao; Shimazaki, Tomomi; Asai, Yoshihiro; Tao, Nongjian

2013-03-06

We report controlling the formation of single-molecule junctions by means of electrochemically reducing two axialdiazonium terminal groups on a molecule, thereby producing direct Au-C covalent bonds in situ between the molecule and gold electrodes. We report a yield enhancement in molecular junction formation as the electrochemical potential of both junction electrodes approach the reduction potential of the diazonium terminal groups. Step length analysis shows that the molecular junction is significantly more stable, and can be pulled over a longer distance than a comparable junction created with amine anchoring bonds. The stability of the junction is explained by the calculated lower binding energy associated with the direct Au-C bond compared with the Au-N bond.

MLN0264 in Previously Treated Asian Participants With Advanced Gastrointestinal Carcinoma or Metastatic or Recurrent Gastric or Gastroesophageal Junction Adenocarcinoma Expressing Guanylyl Cyclase C

ClinicalTrials.gov

2017-02-08

Advanced Gastrointestinal Carcinoma; Gastroesophageal Junction Adenocarcinoma; Recurrent Gastric Adenocarcinoma; Recurrent Gastroesophageal Junction Adenocarcinoma; Metastatic Gastric Adenocarcinoma; Metastatic Gastroesophageal Junction Adenocarcinoma; Recurrent Gastrointestinal Carcinoma

Nasal obstruction and human communication.

PubMed

Malinoff, R; Moreno, C

1989-04-01

Nasal obstruction may cause a variety of communication disorders, particularly in children. The effects of nasal obstruction on hearing, speech, language, and voice are examined. Methods for assessing the effects of nasal obstruction are delineated, and recommendations for therapeutic interventions are described.

Performance comparison between p–i–n and p–n junction tunneling field-effect transistors

NASA Astrophysics Data System (ADS)

Yoon, Young Jun; Seo, Jae Hwa; Kang, In Man

2018-06-01

In this study, we investigated the direct-current (DC) and radio-frequency (RF) performances of p–i–n and p–n junction tunneling field-effect transistors (TFETs). Compared to the p–i–n junction TFET, the p–n junction TFET exhibited higher on-state current (I on) because the channel formation mechanism of the p–n junction TFET resulted in a narrower tunneling barrier and an expanded tunneling area. Further, the reduction of I on of the p–n junction TFET by the interface trap was smaller. Moreover, the p–n junction TFET exhibited lower gate-to-drain capacitance (C gd) because a depletion capacitance (C gd,dep) was formed by the depletion region under gate dielectric. Consequently, the p–n junction TFET achieved an improvement of cut-off frequency (f T) and intrinsic delay time (τ), which are related to the current performance and total gate capacitance (C gg). We confirmed the enhancement of device performances in terms of I on, f T, and τ by the conduction mechanism of the p–n junction TFET.

Tight junctions negatively regulate mechanical forces applied to adherens junctions in vertebrate epithelial tissue.

PubMed

Hatte, Guillaume; Prigent, Claude; Tassan, Jean-Pierre

2018-02-05

Epithelia are layers of polarised cells tightly bound to each other by adhesive contacts. Epithelia act as barriers between an organism and its external environment. Understanding how epithelia maintain their essential integrity while remaining sufficiently plastic to allow events such as cytokinesis to take place is a key biological problem. In vertebrates, the remodelling and reinforcement of adherens junctions maintains epithelial integrity during cytokinesis. The involvement of tight junctions in cell division, however, has remained unexplored. Here, we examine the role of tight junctions during cytokinesis in the epithelium of the Xenopus laevis embryo. Depletion of the tight junction-associated proteins ZO-1 and GEF-H1 leads to altered cytokinesis duration and contractile ring geometry. Using a tension biosensor, we show that cytokinesis defects originate from misregulation of tensile forces applied to adherens junctions. Our results reveal that tight junctions regulate mechanical tension applied to adherens junctions, which in turn impacts cytokinesis.This article has an associated First Person interview with the first author of the paper. © 2018. Published by The Company of Biologists Ltd.

Gap junction-mediated intercellular communication in the immune system.

PubMed

Neijssen, Joost; Pang, Baoxu; Neefjes, Jacques

2007-01-01

Immune cells are usually considered non-attached blood cells, which would exclude the formation of gap junctions. This is a misconception since many immune cells express connexin 43 (Cx43) and other connexins and are often residing in tissue. The role of gap junctions is largely ignored by immunologists as is the immune system in the field of gap junction research. Here, the current knowledge of the distribution of connexins and the function of gap junctions in the immune system is discussed. Gap junctions appear to play many roles in antibody productions and specific immune responses and may be important in sensing danger in tissue by the immune system. Gap junctions not only transfer electrical and metabolical but also immunological information in the form of peptides for a process called cross-presentation. This is essential for proper immune responses to viruses and possibly tumours. Until now only 40 research papers on gap junctions in the immune system appeared and this will almost certainly expand with the increased mutual interest between the fields of immunology and gap junction research.

Outcomes of gynecologic oncology patients undergoing gastrografin small bowel follow-through studies.

PubMed

Walters, Christen L; Sutton, Amelia L M; Huddleston-Colburn, Mary Kathryn; Whitworth, Jenny M; Schneider, Kellie E; Straughn, J Michael

2014-01-01

To characterize the outcomes of gynecologic oncology patients undergoing small bowel follow-throughs (SBFTs) with Gastrografin at our institution. We identified all gynecologic oncology patients undergoing an SBFT from January 2004 to December 2009. We characterized the SBFT as normal, delayed transit, partial obstruction, or complete obstruction. Patient outcomes were correlated with the SBFT results. Seventy patients underwent 79 SBFT examinations with Gastrografin to evaluate their bowel dysfunction. The overall rate of operative intervention was 23%. A total of 69% of patients with a complete obstruction underwent surgery as compared to 21% of patients with a partial obstruction (p = 0.002). Return of bowel function was significantly longer in patients with complete obstructions as compared to patients with partial obstructions (48 vs. 8 hours, p = 0.006). Length of stay was longest in patients with complete obstructions. The majority of patients with a complete obstruction on SBFT will require surgical intervention and have a protracted hospital stay. Patients with delayed transit or a partial obstruction on SBFT usually will have resolution of their bowel dysfunction with conservative management.

76 FR 40293 - Proposed Amendment of Class D and Modification of Class E Airspace; Grand Junction, CO

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-08

... Junction, Walker Field. DATES: Comments must be received on or before August 22, 2011. ADDRESSES: Send... E airspace areas to update the airport name from Grand Junction, Walker Field, to Grand Junction...

76 FR 56966 - Amendment of Class D and Modification of Class E Airspace; Grand Junction, CO

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-15

... and Class E airspace to update the airport name from Grand Junction, Walker Field. DATES: Effective... airspace to update the airport name from Grand Junction, Walker Field, to Grand Junction Regional Airport...

Holographic s-wave and p-wave Josephson junction with backreaction

NASA Astrophysics Data System (ADS)

Wang, Yong-Qiang; Liu, Shuai

2016-11-01

In this paper, we study the holographic models of s-wave and p-wave Josephoson junction away from probe limit in (3+1)-dimensional spacetime, respectively. With the backreaction of the matter, we obtained the anisotropic black hole solution with the condensation of matter fields. We observe that the critical temperature of Josephoson junction decreases with increasing backreaction. In addition to this, the tunneling current and condenstion of Josephoson junction become smaller as backreaction grows larger, but the relationship between current and phase difference still holds for sine function. Moreover, condenstion of Josephoson junction deceases with increasing width of junction exponentially.

Tight junctions and the modulation of barrier function in disease

PubMed Central

2008-01-01

Tight junctions create a paracellular barrier in epithelial and endothelial cells protecting them from the external environment. Two different classes of integral membrane proteins constitute the tight junction strands in epithelial cells and endothelial cells, occludin and members of the claudin protein family. In addition, cytoplasmic scaffolding molecules associated with these junctions regulate diverse physiological processes like proliferation, cell polarity and regulated diffusion. In many diseases, disruption of this regulated barrier occurs. This review will briefly describe the molecular composition of the tight junctions and then present evidence of the link between tight junction dysfunction and disease. PMID:18415116

Multifluxon dynamics in driven Josephson junctions

NASA Astrophysics Data System (ADS)

Lawrence, Albert; Kim, Nung Soo; McDaniel, James; Jack, Michael

1985-06-01

The dynamics of fluxons in a long Josephson junction driven by time-varying nonuniform bias currents are described by a generalization of the sine-Gordon equation. This equation has solitary wave solutions which correspond to current vortices or quantized packets of magnetic flux in the junction. As with the sine-Gordon equation, multifluxon solutions may be demonstrated for the long Josephson junction. Our numerical calculations show that several fluxons may be launched or annihilated at the end of a junction. We also show multiple steady state conditions which correspond to one or more flux quanta trapped in the junction.

Garlic (Allium sativum) feeding impairs Sertoli cell junctional proteins in male Wistar rat testis: microscopy study.

PubMed

Hammami, I; Nahdi, A; Atig, F; El May, A; El May, M V

2016-12-01

Sertoli cell junctions, such as adhesion junction (AJ), gap junction (GJ) and tight junction (TJ), are important for maintaining spermatogenesis. In previous studies, we showed the inhibitory effect of crude garlic (Allium sativum, As) on spermatogenesis and steroidogenesis. The aim of this work was to complete our investigation on the impact of this plant, especially on Sertoli cell junctional proteins (SCJPs). During 1 month, 24 male rats were divided into groups: group control (0% of As) and treated groups fed 5%, 10% and 15% of As. Light and electron microscopy observations were performed to localise junctional proteins: connexin-43, Zona Occluding-1 and N-cadherin (immunohistochemistry) and to describe junctions. We showed that the specific cells involved in the localisation of the SCJP were similar in both control and treated groups, but with different immunoreactivity intensity between them. The electron microscopy observation focused on TJs between Sertoli cells, constituting the blood-testis barrier, showed ultrastructural changes such as fragmentation of TJs between adjacent Sertoli cell membranes and dilatation of rough endoplasmic reticulum saccules giving an aspect of scale to these junctions. We concluded that crude garlic consumption during 1 month induces perturbations on Sertoli cell junctions. These alterations can explain apoptosis in testicular germ cells previously showed. © 2016 Blackwell Verlag GmbH.

Neisseria gonorrhoeae breaches the apical junction of polarized epithelial cells for transmigration by activating EGFR

PubMed Central

Edwards, Vonetta L.; Wang, Liang-Chun; Dawson, Valerie; Stein, Daniel C.; Song, Wenxia

2017-01-01

Summary Neisseria gonorrhoeae initiates infection at the apical surface of columnar endocervical epithelial cells in the female reproductive tract. These cells provide a physical barrier against pathogens by forming continuous apical junctional complexes between neighbouring cells. This study examines the interaction of gonococci (GC) with polarized epithelial cells. We show that viable GC preferentially localize at the apical side of the cell–cell junction in polarized endometrial and colonic epithelial cells, HEC-1-B and T84. In GC-infected cells, continuous apical junctional complexes are disrupted, and the junction-associated protein β-catenin is redistributed from the apical junction to the cytoplasm and to GC adherent sites; however, overall cellular levels remain unchanged. This redistribution of junctional proteins is associated with a decrease in the ‘fence’ function of the apical junction but not its ‘gate’ function. Disruption of the apical junction by removing calcium increases GC transmigration across the epithelial monolayer. GC inoculation induces the phosphorylation of both epidermal growth factor receptor (EGFR) and β-catenin, while inhibition of EGFR kinase activity significantly reduces both GC-induced β-catenin redistribution and GC transmigration. Therefore, the gonococcus is capable of weakening the apical junction and polarity of epithelial cells by activating EGFR, which facilitates GC transmigration across the epithelium. PMID:23279089

Characterization of the column and autocellular junctions that define the vasculature of gill lamellae.

PubMed

Kato, Akira; Nakamura, Korefumi; Kudo, Hisayuki; Tran, Yen Ha; Yamamoto, Yoko; Doi, Hiroyuki; Hirose, Shigehisa

2007-09-01

Novel adhesion junctions have been characterized that are formed at the interface between pillar cells and collagen columns, both of which are essential constituents of the gill lamellae in fish. We termed these junctions the "column junction" and "autocellular junction" and determined their molecular compositions by immunofluorescence microscopy using pufferfish. We visualized collagen columns by concanavalin A staining and found that the components of integrin-mediated cell-matrix adhesion, such as talin, vinculin, paxillin, and fibronectin, were concentrated on plasma membranes surrounding collagen columns (column membranes). This connection is analogous to the focal adhesion of cultured mammalian cells, dense plaque of smooth muscle cells, and myotendinous junction of skeletal muscle cells. We named this connection the "column junction." In the cytoplasm near the column, actin fibers, actinin, and a phosphorylated myosin light chain of 20 kDa are densely located, suggesting the contractile nature of pillar cells. The membrane infoldings surrounding the collagen columns were found to be connected by the autocellular junction, whose components are highly tyrosine-phosphorylated and contain the tight junction protein ZO-1. This study represents the first molecular characterization and fluorescence visualization of the column and autocellular junctions involved in both maintaining structural integrity and the hemodynamics of the branchial lamellae.

Tight junctions and human diseases.

PubMed

Sawada, Norimasa; Murata, Masaki; Kikuchi, Keisuke; Osanai, Makoto; Tobioka, Hirotoshi; Kojima, Takashi; Chiba, Hideki

2003-09-01

Tight junctions are intercellular junctions adjacent to the apical end of the lateral membrane surface. They have two functions, the barrier (or gate) function and the fence function. The barrier function of tight junctions regulates the passage of ions, water, and various macromolecules, even of cancer cells, through paracellular spaces. The barrier function is thus relevant to edema, jaundice, diarrhea, and blood-borne metastasis. On the other hand, the fence function maintains cell polarity. In other words, tight junctions work as a fence to prevent intermixing of molecules in the apical membrane with those in the lateral membrane. This function is deeply involved in cancer cell biology, in terms of loss of cell polarity. Of the proteins comprising tight junctions, integral membrane proteins occludin, claudins, and JAMs have been recently discovered. Of these molecules, claudins are exclusively responsible for the formation of tight-junction strands and are connected with the actin cytoskeleton mediated by ZO-1. Thus, both functions of tight junctions are dependent on the integrity of the actin cytoskeleton as well as ATP. Mutations in the claudin14 and the claudin16 genes result in hereditary deafness and hereditary hypomagnesemia, respectively. Some pathogenic bacteria and viruses target and affect the tight-junction function, leading to diseases. In this review, the relationship between tight junctions and human diseases is summarized.

Synaptopodin couples epithelial contractility to α-actinin-4–dependent junction maturation

PubMed Central

Kannan, Nivetha

2015-01-01

The epithelial junction experiences mechanical force exerted by endogenous actomyosin activities and from interactions with neighboring cells. We hypothesize that tension generated at cell–cell adhesive contacts contributes to the maturation and assembly of the junctional complex. To test our hypothesis, we used a hydraulic apparatus that can apply mechanical force to intercellular junction in a confluent monolayer of cells. We found that mechanical force induces α-actinin-4 and actin accumulation at the cell junction in a time- and tension-dependent manner during junction development. Intercellular tension also induces α-actinin-4–dependent recruitment of vinculin to the cell junction. In addition, we have identified a tension-sensitive upstream regulator of α-actinin-4 as synaptopodin. Synaptopodin forms a complex containing α-actinin-4 and β-catenin and interacts with myosin II, indicating that it can physically link adhesion molecules to the cellular contractile apparatus. Synaptopodin depletion prevents junctional accumulation of α-actinin-4, vinculin, and actin. Knockdown of synaptopodin and α-actinin-4 decreases the strength of cell–cell adhesion, reduces the monolayer permeability barrier, and compromises cellular contractility. Our findings underscore the complexity of junction development and implicate a control process via tension-induced sequential incorporation of junctional components. PMID:26504173

Severity of Airflow Obstruction in Chronic Obstructive Pulmonary Disease (COPD): Proposal for a New Classification.

PubMed

Coton, Sonia; Vollmer, William M; Bateman, Eric; Marks, Guy B; Tan, Wan; Mejza, Filip; Juvekar, Sanjay; Janson, Christer; Mortimer, Kevin; P A, Mahesh; Buist, A Sonia; Burney, Peter G J

2017-10-01

Current classifications of Chronic Obstructive Pulmonary Disease (COPD) severity are complex and do not grade levels of obstruction. Obstruction is a simpler construct and independent of ethnicity. We constructed an index of obstruction severity based on the FEV 1 /FVC ratio, with cut-points dividing the Burden of Obstructive Lung Disease (BOLD) study population into four similarly sized strata to those created by the GOLD criteria that uses FEV 1 . We measured the agreement between classifications and the validity of the FEV 1 -based classification in identifying the level of obstruction as defined by the new groupings. We compared the strengths of association of each classification with quality of life (QoL), MRC dyspnoea score and the self-reported exacerbation rate. Agreement between classifications was only fair. FEV 1 -based criteria for moderate COPD identified only 79% of those with moderate obstruction and misclassified half of the participants with mild obstruction as having more severe COPD. Both scales were equally strongly associated with QoL, exertional dyspnoea and respiratory exacerbations. Severity assessed using the FEV 1 /FVC ratio is only in moderate agreement with the severity assessed using FEV 1 but is equally strongly associated with other outcomes. Severity assessed using the FEV 1 /FVC ratio is likely to be independent of ethnicity.

The effect of bladder outlet obstruction on tissue oxygen tension and blood flow in the pig bladder.

PubMed

Greenland, J E; Hvistendahl, J J; Andersen, H; Jörgensen, T M; McMurray, G; Cortina-Borja, M; Brading, A F; Frøkiaer, J

2000-06-01

To investigate the effect of partial bladder outlet obstruction on detrusor blood flow and oxygen tension (PdetO2) in female pigs. Detrusor-layer oxygen tension and blood flow were measured using oxygen-sensitive electrode and radiolabelled microsphere techniques in five female Large White pigs with a partial urethral obstruction and in five sham-operated controls. The effects of chronic outlet obstruction on bladder weight, and cholinergic nerve density and distribution, are also described. In the obstructed bladders, blood flow and oxygen tension were, respectively, 54.9% and 74.3% of control values at low bladder volume, and 47.5% and 42.5% at cystometric capacity. Detrusor blood flow declined by 27.8% and 37.5% in the control and obstructed bladders, respectively, as a result of bladder filling, whilst PdetO2 did not decrease in the controls, but fell by 42.7% in the obstructed bladders. Bladder weight increased whilst cholinergic nerve density decreased in the obstructed animals. In pigs with chronic bladder outlet obstruction, blood flow and oxygen tension in the detrusor layer were lower than in control animals. In addition, increasing detrusor pressure during filling caused significantly greater decreases in blood flow and oxygen tension in the obstructed than in the control bladders.

Analyzing phorbol ester effects on gap junctional communication: a dramatic inhibition of assembly

PubMed Central

1994-01-01

The effect of 12-O-tetradeconylphorbol-13-acetate (TPA) on gap junction assembly between Novikoff hepatoma cells was examined. Cells were dissociated with EDTA to single cells and then reaggregated to form new junctions. When TPA (25 nM) was added to the cells at the onset of the 60-min reaggregation, dye transfer was detected at only 0.6% of the cell-cell interfaces compared to 72% for the untreated control and 74% for 4-alpha TPA, an inactive isomer of TPA. Freeze-fracture electron microscopy of reaggregated control cells showed interfaces containing an average of more than 600 aggregated intramembranous gap junction particles, while TPA-treated cells had no gap junctions. However, Lucifer yellow dye transfer between nondissociated cells via gap junctions was unaffected by 60 min of TPA treatment. Therefore, TPA dramatically inhibited gap junction assembly but did not alter channel gating nor enhance disassembly of preexisting gap junction structures. Short term TPA treatment (< 30 min) increased phosphorylation of the gap junction protein molecular weight of 43,000 (Cx43), but did not change the cellular level of Cx43. Cell surface biotinylation experiments suggested that TPA did not substantially reduce the plasma membrane concentration of Cx43. Therefore, the simple presence of Cx43 in the plasma membrane is not sufficient for gap junction assembly, and protein kinase C probably exerts an effect on assembly of gap junctions at the plasma membrane level. PMID:7806568

Design of thin InGaAsN(Sb) n-i-p junctions for use in four-junction concentrating photovoltaic devices

NASA Astrophysics Data System (ADS)

Wilkins, Matthew M.; Gupta, James; Jaouad, Abdelatif; Bouzazi, Boussairi; Fafard, Simon; Boucherif, Abderraouf; Valdivia, Christopher E.; Arès, Richard; Aimez, Vincent; Schriemer, Henry P.; Hinzer, Karin

2017-04-01

Four-junction solar cells for space and terrestrial applications require a junction with a band gap of ˜1 eV for optimal performance. InGaAsN or InGaAsN(Sb) dilute nitride junctions have been demonstrated for this purpose, but in achieving the 14 mA/cm2 short-circuit current needed to match typical GaInP and GaAs junctions, the open-circuit voltage (VOC) and fill factor of these junctions are compromised. In multijunction devices incorporating materials with short diffusion lengths, we study the use of thin junctions to minimize sensitivity to varying material quality and ensure adequate transmission into lower junctions. An n-i-p device with 0.65-μm absorber thickness has sufficient short-circuit current, however, it relies less heavily on field-aided collection than a device with a 1-μm absorber. Our standard cell fabrication process, which includes a rapid thermal anneal of the contacts, yields a significant improvement in diffusion length and device performance. By optimizing a four-junction cell around a smaller 1-sun short-circuit current of 12.5 mA/cm2, we produced an InGaAsN(Sb) junction with open-circuit voltage of 0.44 V at 1000 suns (1 sun=100 mW/cm2), diode ideality factor of 1.4, and sufficient light transmission to allow >12.5 mA/cm2 in all four subcells.

Shear zone junctions: Of zippers and freeways

NASA Astrophysics Data System (ADS)

Passchier, Cees W.; Platt, John P.

2017-02-01

Ductile shear zones are commonly treated as straight high-strain domains with uniform shear sense and characteristic curved foliation trails, bounded by non-deforming wall rock. Many shear zones, however, are branched, and if movement on such branches is contemporaneous, the resulting shape can be complicated and lead to unusual shear sense arrangement and foliation geometries in the wall rock. For Y-shaped shear zone triple junctions with three joining branches and transport direction at a high angle to the branchline, only eight basic types of junction are thought to be stable and to produce significant displacement. The simplest type, called freeway junctions, have similar shear sense in all three branches. The other types show joining or separating behaviour of shear zone branches similar to the action of a zipper. Such junctions may have shear zone branches that join to form a single branch (closing zipper junction), or a single shear zone that splits to form two branches, (opening zipper junction). All categories of shear zone junctions show characteristic foliation patterns and deflection of markers in the wall rock. Closing zipper junctions are unusual, since they form a non-active zone with opposite deflection of foliations in the wall rock known as an extraction fault or wake. Shear zipper junctions can form domains of overprinting shear sense along their flanks. A small and large field example are given from NE Spain and Eastern Anatolia. The geometry of more complex, 3D shear zone junctions with slip parallel and oblique to the branchline is briefly discussed.

Justification of Structural and Technological Solutions on Junction Perfecting on Permyakova and Shirotnaya Streets Intersection in Tyumen

NASA Astrophysics Data System (ADS)

Sannikov, S. P.; Timohovetz, V. D.; Kuzuek, A. Y.

2017-11-01

This article presents the justification of structurally-technological decisions on a junction perfecting on the intersection of Permyakova and Shirotnaya Streets in Tyumen. The authors made a comparative analysis of typical road junctions. Based on the comparison, the engineering decisions were made for an individual type of transport junctions. Several options of individual design were proposed and analyzed and three most suitable types for the road junctions were offered. On the basis of a multilateral studying and evaluation of the developed transport the article further proposed a transport junction with change-side traffic. The use of this type of intersection will increase the road junction capacity, reduce the number of accidents due to conflicting flows reduction which, in its turn, will increase the speed of cars.

Switching and Rectification in Carbon-Nanotube Junctions

NASA Technical Reports Server (NTRS)

Srivastava, Deepak; Andriotis, Antonis N.; Menon, Madhu; Chernozatonskii, Leonid

2003-01-01

Multi-terminal carbon-nanotube junctions are under investigation as candidate components of nanoscale electronic devices and circuits. Three-terminal "Y" junctions of carbon nanotubes (see Figure 1) have proven to be especially interesting because (1) it is now possible to synthesize them in high yield in a controlled manner and (2) results of preliminary experimental and theoretical studies suggest that such junctions could exhibit switching and rectification properties. Following the preliminary studies, current-versus-voltage characteristics of a number of different "Y" junctions of single-wall carbon nanotubes connected to metal wires were computed. Both semiconducting and metallic nanotubes of various chiralities were considered. Most of the junctions considered were symmetric. These computations involved modeling of the quantum electrical conductivity of the carbon nanotubes and junctions, taking account of such complicating factors as the topological defects (pentagons, heptagons, and octagons) present in the hexagonal molecular structures at the junctions, and the effects of the nanotube/wire interfaces. A major component of the computational approach was the use of an efficient Green s function embedding scheme. The results of these computations showed that symmetric junctions could be expected to support both rectification and switching. The results also showed that rectification and switching properties of a junction could be expected to depend strongly on its symmetry and, to a lesser degree, on the chirality of the nanotubes. In particular, it was found that a zigzag nanotube branching at a symmetric "Y" junction could exhibit either perfect rectification or partial rectification (asymmetric current-versus-voltage characteristic, as in the example of Figure 2). It was also found that an asymmetric "Y" junction would not exhibit rectification.

Poster - Thur Eve - 57: Craniospinal irradiation with jagged-junction IMRT approach without beam edge matching for field junctions.

PubMed

Cao, F; Ramaseshan, R; Corns, R; Harrop, S; Nuraney, N; Steiner, P; Aldridge, S; Liu, M; Carolan, H; Agranovich, A; Karva, A

2012-07-01

Craniospinal irradiation were traditionally treated the central nervous system using two or three adjacent field sets. A intensity-modulated radiotherapy (IMRT) plan (Jagged-Junction IMRT) which overcomes problems associated with field junctions and beam edge matching, improves planning and treatment setup efficiencies with homogenous target dose distribution was developed. Jagged-Junction IMRT was retrospectively planned on three patients with prescription of 36 Gy in 20 fractions and compared to conventional treatment plans. Planning target volume (PTV) included the whole brain and spinal canal to the S3 vertebral level. The plan employed three field sets, each with a unique isocentre. One field set with seven fields treated the cranium. Two field sets treated the spine, each set using three fields. Fields from adjacent sets were overlapped and the optimization process smoothly integrated the dose inside the overlapped junction. For the Jagged-Junction IMRT plans vs conventional technique, average homogeneity index equaled 0.08±0.01 vs 0.12±0.02, and conformity number equaled 0.79±0.01 vs 0.47±0.12. The 95% isodose surface covered (99.5±0.3)% of the PTV vs (98.1±2.0)%. Both Jagged-Junction IMRT plans and the conventional plans had good sparing of the organs at risk. Jagged-Junction IMRT planning provided good dose homogeneity and conformity to the target while maintaining a low dose to the organs at risk. Jagged-Junction IMRT optimization smoothly distributed dose in the junction between field sets. Since there was no beam matching, this treatment technique is less likely to produce hot or cold spots at the junction in contrast to conventional techniques. © 2012 American Association of Physicists in Medicine.

dc properties of series-parallel arrays of Josephson junctions in an external magnetic field

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

Lewandowski, S.J.

1991-04-01

A detailed dc theory of superconducting multijunction interferometers has previously been developed by several authors for the case of parallel junction arrays. The theory is now extended to cover the case of a loop containing several junctions connected in series. The problem is closely associated with high-{ital T}{sub {ital c}} superconductors and their clusters of intrinsic Josephson junctions. These materials exhibit spontaneous interferometric effects, and there is no reason to assume that the intrinsic junctions form only parallel arrays. A simple formalism of phase states is developed in order to express the superconducting phase differences across the junctions forming amore » series array as functions of the phase difference across the weakest junction of the system, and to relate the differences in critical currents of the junctions to gaps in the allowed ranges of their phase functions. This formalism is used to investigate the energy states of the array, which in the case of different junctions are split and separated by energy barriers of height depending on the phase gaps. Modifications of the washboard model of a single junction are shown. Next a superconducting inductive loop containing a series array of two junctions is considered, and this model is used to demonstrate the transitions between phase states and the associated instabilities. Finally, the critical current of a parallel connection of two series arrays is analyzed and shown to be a multivalued function of the externally applied magnetic flux. The instabilities caused by the presence of intrinsic serial junctions in granular high-{ital T}{sub {ital c}} materials are pointed out as a potential source of additional noise.« less

The prevalence of increased proximal junctional flexion following posterior instrumentation and arthrodesis for adolescent idiopathic scoliosis.

PubMed

Hollenbeck, S Matt; Glattes, R Christopher; Asher, Marc A; Lai, Sue Min; Burton, Douglas C

2008-07-01

Retrospective case series. To determine the prevalence of proximal junctional sagittal plane flexion increase after posterior instrumentation and arthrodesis. Increased flexion proximal to the junction of the instrumented and fused spinal region with the adjacent mobile spine seems to be a relatively recent observation, may be increasing, and is occasionally problematic. The proximal junctional sagittal angulation 2 motion segments above the upper end instrumentation levels was measured on lateral standing preoperative and follow-up radiographs. One hundred seventy-four of 208 consecutive patients (84%) at an average radiograph follow-up of 4.9 +/- 2.73 years had increased proximal junctional flexion in 9.2%. The preoperative junctional measurements were normal for both normal and increased flexion groups. At follow-up, proximal junctional flexion had increased significantly more in the increased flexion group (2.1 degrees vs. 14.1 degrees , P < 0.0001). None of the possible risk factors studied, including demographic comparisons, Lenke classification (including lumbar and sagittal modifiers), end-instrumented vertebrae, end vertebra anchor configurations, surgical sequence, additional anterior surgery, rib osteotomies, and instrumentation length, were significantly associated with increased proximal junctional flexion at follow-up. Lenke 6 curves were at marginal risk of increased proximal junctional flexion (P = 0.0108). There were no differences between the groups in total Scoliosis Research Society-22r scores at an average follow-up of 8.0 +/- 3.74 years. No patient had additional surgery related to increased proximal junctional flexion. The prevalence of increased proximal junctional flexion was 9.2%. No significant risk factors were identified. Total Scoliosis Research Society-22r scores were similar for groups with normal and increased proximal junctional flexion at follow-up.

Application of small intestine decompression combined with oral feeding in middle and late period of malignant small bowel obstruction.

PubMed

Li, Dechun; Du, Hongtao; Shao, Guoqing; Guo, Yongtuan; Lu, Wan; Li, Ruihong

2017-07-01

The application value of small intestine decompression combined with oral feeding in the middle and late period of malignant small bowel obstruction was examined. A total of 22 patients with advanced malignant small bowel obstruction were included in the present study. An ileus tube was inserted via the nose under fluoroscopy into the obstructed small intestine of each patient. At the same time, the insertion depth the of the catheter was adjusted. When the catheter was blocked, small bowel selective angiography was performed to determine the location and cause of the obstruction and the extent of the obstruction, and to determine the length of the small intestine in the site of obstruction, and to select the variety and tolerance of enteral nutrition. We observed the decompression tube flow and ease of intestinal obstruction. In total, 20 patients were treated with oral enteral nutrition after abdominal distension, and 22 cases were treated by the nose to observe the drainage and the relief of intestinal obstruction. The distal end of the catheter was placed in a predetermined position. The symptoms of intestinal obstruction were relieved 1-4 days after decompression. The 22 patients with selective angiography of the small intestine showed positive X-ray signs: 18 patients with oral enteral nutrition therapy had improved the nutritional situation 2 weeks later. In 12 cases, where there was anal defecation exhaust, 2 had transient removal of intestinal obstruction catheter. In conclusion, this comprehensive treatment based on small intestine decompression combined with enteral nutrition is expected to become a new therapeutic approach and method for the treatment of patients with advanced tumor small bowel obstruction.

Sleep Architecture Linked to Airway Obstruction and Intracranial Hypertension in Children with Syndromic Craniosynostosis.

PubMed

Spruijt, Bart; Mathijssen, Irene M J; Bredero-Boelhouwer, Hansje H; Cherian, Perumpillichira J; Corel, Linda J A; van Veelen, Marie-Lise; Hayward, Richard D; Tasker, Robert C; Joosten, Koen F M

2016-12-01

Children with syndromic craniosynostosis often have obstructive sleep apnea and intracranial hypertension. The authors aimed to evaluate (1) sleep architecture, and determine whether this is influenced by the presence of obstructive sleep apnea and/or intracranial hypertension; and (2) the effect of treatment on sleep architecture. This study included patients with syndromic craniosynostosis treated at a national referral center, undergoing screening for obstructive sleep apnea and intracranial hypertension. Obstructive sleep apnea was identified by polysomnography, and categorized into no, mild, moderate, or severe. Intracranial hypertension was identified by the presence of papilledema on funduscopy, supplemented by optical coherence tomography and/or intracranial pressure monitoring. Regarding sleep architecture, sleep was divided into rapid eye movement or non-rapid eye movement sleep; respiratory effort-related arousals and sleep efficiency were scored. The authors included 39 patients (median age, 5.9 years): 19 with neither obstructive sleep apnea nor intracranial hypertension, 11 with obstructive sleep apnea (four moderate/severe), six with intracranial hypertension, and three with obstructive sleep apnea and intracranial hypertension. Patients with syndromic craniosynostosis, independent of the presence of mild obstructive sleep apnea and/or intracranial hypertension, have normal sleep architecture compared with age-matched controls. Patients with moderate/severe obstructive sleep apnea have a higher respiratory effort-related arousal index (p < 0.01), lower sleep efficiency (p = 0.01), and less rapid eye movement sleep (p = 0.04). An improvement in sleep architecture was observed following monobloc surgery (n = 5; rapid eye movement sleep, 5.3 percent; p = 0.04). Children with syndromic craniosynostosis have in principle normal sleep architecture. However, moderate/severe obstructive sleep apnea does lead to disturbed sleep architecture, which fits within a framework of a unifying theory for obstructive sleep apnea, intracranial hypertension, and sleep. Risk, II.

High voltage series connected tandem junction solar battery

DOEpatents

Hanak, Joseph J.

1982-01-01

A high voltage series connected tandem junction solar battery which comprises a plurality of strips of tandem junction solar cells of hydrogenated amorphous silicon having one optical path and electrically interconnected by a tunnel junction. The layers of hydrogenated amorphous silicon, arranged in a tandem configuration, can have the same bandgap or differing bandgaps. The tandem junction strip solar cells are series connected to produce a solar battery of any desired voltage.

Prognostic effects of preoperative obstructive pneumonitis or atelectasis and comparison with tumor size in non-small cell lung cancer

PubMed Central

Pang, Zhaofei; Ding, Nan; Dong, Wei; Ni, Yang; Zhang, Tiehong; Qu, Xiao

2017-01-01

Background In the eighth TNM staging system proposal, lung cancer with part or complete obstructive pneumonitis/atelectasis was classified to T2 category, and dividing lines of T category were changed. We conducted this study to search prognostic effect of preoperative obstructive pneumonitis/atelectasis and its comparison with tumor size. Methods We collected clinical characteristics, preoperative hematological indicators, follow-up information of 1,313 lung cancer patients. Chi-square test was used to search relationship between obstruction pneumonitis/atelectasis and other factors. Kaplan-Meier (K-M) curves and cox regression methods were used for survival analysis. Results Preoperative obstructive pneumonitis/atelectasis indicated shorter OS (HR: 1.308; 95% CI: 1.058–1.619) and RFS (HR: 1.276; 95% CI: 1.032–1.579) as an independent factor. In comparison with tumor size, we found patients with obstructive pneumonitis/atelectasis and T1 size tumor had similar prognosis to those with T2 size but without obstructive pneumonitis/atelectasis, and OS, RFS of patients with obstructive pneumonitis/atelectasis and T2 size were significantly shorter than those with T2 tumor size but without obstructive pneumonitis/atelectasis, while similar to patients with T3 tumor size but without obstructive pneumonitis/atelectasis according to division by the eighth edition. We also found obstructive pneumonitis/atelectasis was significantly related to higher neutrophil (P<0.001), platelet (P<0.001), monocyte (P<0.001), NLR (P<0.001), PLR (P=0.002), ESR (P<0.001) and lower LMR (P<0.001). Conclusions Preoperative obstructive pneumonitis/atelectasis predicted poor survival independently in non-small cell lung cancer (NSCLC). And we suggested which T staging group the patients with obstructive pneumonitis/atelectasis would be divided to should depend on tumor size in the eighth TNM staging system. PMID:28449485

Rapamycin attenuates bladder hypertrophy during long-term outlet obstruction in vivo: tissue, matrix and mechanistic insights.

PubMed

Schröder, Annette; Kirwan, Tyler P; Jiang, Jia-Xin; Aitken, Karen J; Bägli, Darius J

2013-06-01

Previous molecular studies showed that the mTOR inhibitor rapamycin prevents bladder smooth muscle hypertrophy in vitro. We investigated the effect of rapamycin treatment in vivo on bladder smooth muscle hypertrophy in a rat model of partial bladder outlet obstruction. A total of 48 female Sprague-Dawley® rats underwent partial bladder outlet obstruction and received daily subcutaneous injections of rapamycin (1 mg/kg) or vehicle commencing 2 weeks postoperatively. A total of 36 rats underwent sham surgery and received rapamycin or vehicle. Rats were sacrificed 3, 6 and 12 weeks after surgery. Before sacrifice, voiding was observed in a metabolic cage for 24 hours. Bladder-to-body weight in gm bladder weight per kg body weight and post-void residual urine were assessed. We evaluated Col1a1, Col3a1, Eln and Mmp7 mRNA expression and histology. Two-factor ANOVA and the post hoc t test were applied. Bladder outlet obstruction caused a significant increase in bladder weight in all obstructed groups. Three weeks postoperatively (1 week of treatment) there was no difference in the bladder-to-body weight ratio in the obstructed group. However, at 6 and 12 weeks (4 and 10 weeks of treatment, respectively) the bladder-to-body weight ratio of rats with obstruction plus rapamycin was significantly lower than that of rats with obstruction plus vehicle. Post-void residual urine volume after 6 and 12 weeks of obstruction was lower in obstructed rats with rapamycin compared to that in obstructed rats with vehicle. Rapamycin decreased the obstruction induced expression of Col1a1, Col3a1, Eln and Mmp7. Rapamycin prevents mechanically induced hypertrophy in cardiovascular smooth muscle. In vivo mTOR inhibition may attenuate obstruction induced detrusor hypertrophy and help preserve bladder function. Copyright © 2013 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

CHLORAL HYDRATE DECREASES GAP JUNCTION COMMUNICATION IN RAT LIVER EPITHELIAL CELLS

EPA Science Inventory

Chloral hydrate decreases gap junction communication in rat liver epithelial cells

Gap junction communication (GJC) is involved in controlling cell proliferation and differentiation. Connexins (Cx) that make up these junctions are composed of a closely related group of m...

Monocytic cell junction proteins serve important roles in atherosclerosis via the endoglin pathway

PubMed Central

Chen, Lina; Chen, Zhongliang; Ge, Menghua; Tang, Oushan; Cheng, Yinhong; Zhou, Haoliang; Shen, Yu; Qin, Fengming

2017-01-01

The formation of atherosclerosis is recognized to be caused by multiple factors including pathogenesis in monocytes during inflammation. The current study provided evidence that monocytic junctions were significantly altered in patients with atherosclerosis, which suggested an association between cell junctions and atherosclerosis. Claudin-1, occludin-1 and ZO-1 were significantly enhanced in atherosclerosis, indicating that the tight junction pathway was activated during the pathogenesis of atherosclerosis. In addition, the gene expression of 5 connexin members involved in the gap junction pathway were quantified, indicating that connexin 43 and 46 were significantly up-regulated in atherosclerosis. Furthermore, inflammatory factors including endoglin and SMAD were observed, suggesting that immune regulative factors were down-regulated in this pathway. Silicon-based analysis additionally identified that connexins and tight junctions were altered in association with monocytic inflammation regulations, endoglin pathway. The results imply that reduced expression of the immune regulation pathway in monocytes is correlated with the generation of gap junctions and tight junctions which serve important roles in atherosclerosis. PMID:28901429

A generic concept to overcome bandgap limitations for designing highly efficient multi-junction photovoltaic cells

PubMed Central

Guo, Fei; Li, Ning; Fecher, Frank W.; Gasparini, Nicola; Quiroz, Cesar Omar Ramirez; Bronnbauer, Carina; Hou, Yi; Radmilović, Vuk V.; Radmilović, Velimir R.; Spiecker, Erdmann; Forberich, Karen; Brabec, Christoph J.

2015-01-01

The multi-junction concept is the most relevant approach to overcome the Shockley–Queisser limit for single-junction photovoltaic cells. The record efficiencies of several types of solar technologies are held by series-connected tandem configurations. However, the stringent current-matching criterion presents primarily a material challenge and permanently requires developing and processing novel semiconductors with desired bandgaps and thicknesses. Here we report a generic concept to alleviate this limitation. By integrating series- and parallel-interconnections into a triple-junction configuration, we find significantly relaxed material selection and current-matching constraints. To illustrate the versatile applicability of the proposed triple-junction concept, organic and organic-inorganic hybrid triple-junction solar cells are constructed by printing methods. High fill factors up to 68% without resistive losses are achieved for both organic and hybrid triple-junction devices. Series/parallel triple-junction cells with organic, as well as perovskite-based subcells may become a key technology to further advance the efficiency roadmap of the existing photovoltaic technologies. PMID:26177808

A generic concept to overcome bandgap limitations for designing highly efficient multi-junction photovoltaic cells.

PubMed

Guo, Fei; Li, Ning; Fecher, Frank W; Gasparini, Nicola; Ramirez Quiroz, Cesar Omar; Bronnbauer, Carina; Hou, Yi; Radmilović, Vuk V; Radmilović, Velimir R; Spiecker, Erdmann; Forberich, Karen; Brabec, Christoph J

2015-07-16

The multi-junction concept is the most relevant approach to overcome the Shockley-Queisser limit for single-junction photovoltaic cells. The record efficiencies of several types of solar technologies are held by series-connected tandem configurations. However, the stringent current-matching criterion presents primarily a material challenge and permanently requires developing and processing novel semiconductors with desired bandgaps and thicknesses. Here we report a generic concept to alleviate this limitation. By integrating series- and parallel-interconnections into a triple-junction configuration, we find significantly relaxed material selection and current-matching constraints. To illustrate the versatile applicability of the proposed triple-junction concept, organic and organic-inorganic hybrid triple-junction solar cells are constructed by printing methods. High fill factors up to 68% without resistive losses are achieved for both organic and hybrid triple-junction devices. Series/parallel triple-junction cells with organic, as well as perovskite-based subcells may become a key technology to further advance the efficiency roadmap of the existing photovoltaic technologies.

Direct analysis of Holliday junction resolving enzyme in a DNA origami nanostructure.

PubMed

Suzuki, Yuki; Endo, Masayuki; Cañas, Cristina; Ayora, Silvia; Alonso, Juan C; Sugiyama, Hiroshi; Takeyasu, Kunio

2014-06-01

Holliday junction (HJ) resolution is a fundamental step for completion of homologous recombination. HJ resolving enzymes (resolvases) distort the junction structure upon binding and prior cleavage, raising the possibility that the reactivity of the enzyme can be affected by a particular geometry and topology at the junction. Here, we employed a DNA origami nano-scaffold in which each arm of a HJ was tethered through the base-pair hybridization, allowing us to make the junction core either flexible or inflexible by adjusting the length of the DNA arms. Both flexible and inflexible junctions bound to Bacillus subtilis RecU HJ resolvase, while only the flexible junction was efficiently resolved into two duplexes by this enzyme. This result indicates the importance of the structural malleability of the junction core for the reaction to proceed. Moreover, cleavage preferences of RecU-mediated reaction were addressed by analyzing morphology of the reaction products. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

GaAs nanowire array solar cells with axial p-i-n junctions.

PubMed

Yao, Maoqing; Huang, Ningfeng; Cong, Sen; Chi, Chun-Yung; Seyedi, M Ashkan; Lin, Yen-Ting; Cao, Yu; Povinelli, Michelle L; Dapkus, P Daniel; Zhou, Chongwu

2014-06-11

Because of unique structural, optical, and electrical properties, solar cells based on semiconductor nanowires are a rapidly evolving scientific enterprise. Various approaches employing III-V nanowires have emerged, among which GaAs, especially, is under intense research and development. Most reported GaAs nanowire solar cells form p-n junctions in the radial direction; however, nanowires using axial junction may enable the attainment of high open circuit voltage (Voc) and integration into multijunction solar cells. Here, we report GaAs nanowire solar cells with axial p-i-n junctions that achieve 7.58% efficiency. Simulations show that axial junctions are more tolerant to doping variation than radial junctions and lead to higher Voc under certain conditions. We further study the effect of wire diameter and junction depth using electrical characterization and cathodoluminescence. The results show that large diameter and shallow junctions are essential for a high extraction efficiency. Our approach opens up great opportunity for future low-cost, high-efficiency photovoltaics.

Advance of Mechanically Controllable Break Junction for Molecular Electronics.

PubMed

Wang, Lu; Wang, Ling; Zhang, Lei; Xiang, Dong

2017-06-01

Molecular electronics stands for the ultimate size of functional elements, keeping up with an unstoppable trend over the past few decades. As a vital component of molecular electronics, single molecular junctions have attracted significant attention from research groups all over the world. Due to its pronounced superiority, the mechanically controllable break junctions (MCBJ) technique has been widely applied to characterize the dynamic performance of single molecular junctions. This review presents a system analysis for single-molecule junctions and offers an overview of four test-beds for single-molecule junctions, thus offering more insight into the mechanisms of electron transport. We mainly focus on the development of state-of-the-art mechanically controlled break junctions. The three-terminal gated MCBJ approaches are introduced to manipulate the electron transport of molecules, and MCBJs are combined with characterization techniques. Additionally, applications of MCBJs and remarkable properties of single molecules are addressed. Finally, the challenges and perspective for the mechanically controllable break junctions technique are provided.

Myosin-dependent remodeling of adherens junctions protects junctions from Snail-dependent disassembly

PubMed Central

Weng, Mo

2016-01-01

Although Snail is essential for disassembly of adherens junctions during epithelial–mesenchymal transitions (EMTs), loss of adherens junctions in Drosophila melanogaster gastrula is delayed until mesoderm is internalized, despite the early expression of Snail in that primordium. By combining live imaging and quantitative image analysis, we track the behavior of E-cadherin–rich junction clusters, demonstrating that in the early stages of gastrulation most subapical clusters in mesoderm not only persist, but move apically and enhance in density and total intensity. All three phenomena depend on myosin II and are temporally correlated with the pulses of actomyosin accumulation that drive initial cell shape changes during gastrulation. When contractile myosin is absent, the normal Snail expression in mesoderm, or ectopic Snail expression in ectoderm, is sufficient to drive early disassembly of junctions. In both cases, junctional disassembly can be blocked by simultaneous induction of myosin contractility. Our findings provide in vivo evidence for mechanosensitivity of cell–cell junctions and imply that myosin-mediated tension can prevent Snail-driven EMT. PMID:26754645

ER-plasma membrane junctions: Why and how do we study them?

PubMed

Chang, Chi-Lun; Chen, Yu-Ju; Liou, Jen

2017-09-01

Endoplasmic reticulum (ER)-plasma membrane (PM) junctions are membrane microdomains important for communication between the ER and the PM. ER-PM junctions were first reported in muscle cells in 1957, but mostly ignored in non-excitable cells due to their scarcity and lack of functional significance. In 2005, the discovery of stromal interaction molecule 1 (STIM1) mediating a universal Ca 2+ feedback mechanism at ER-PM junctions in mammalian cells led to a resurgence of research interests toward ER-PM junctions. In the past decade, several major advancements have been made in this emerging topic in cell biology, including the generation of tools for labeling ER-PM junctions and the unraveling of mechanisms underlying regulation and functions of ER-PM junctions. This review summarizes early studies, recently developed tools, and current advances in the characterization and understanding of ER-PM junctions. This article is part of a Special Issue entitled: Membrane Contact Sites edited by Christian Ungermann and Benoit Kornmann. Copyright © 2017 Elsevier B.V. All rights reserved.

Laparoscopic gastropexy relieves symptoms of obstructed gastric volvulus in highoperative risk patients.

PubMed

Yates, Robert B; Hinojosa, Marcelo W; Wright, Andrew S; Pellegrini, Carlos A; Oelschlager, Brant K

2015-05-01

Operative repair of obstructive gastric volvulus is challenging. In high-operative risk patients with obstructive gastric volvulus, we perform laparoscopic reduction of gastric volvulus and anterior abdominal wall sutured gastropexy. This case series reports our experience with this operation. We reviewed the charts of all patients who presented with obstructive gastric volvulus and underwent laparoscopic gastropexy between 2007 and 2013. Eleven patients underwent laparoscopic gastropexy. Median age was 83 years (50 to 92). Six patients presented with chronic obstruction; 5 presented with acute obstruction. Median postoperative hospitalization was 2 days (1 to 39). Two patients required reoperation for displaced gastrostomy tubes. At median follow-up of 3 months (2 weeks to 57 months), all patients remained free of gastric obstructive symptoms and recurrent episodes of volvulus. Only 1 patient received nutrition via gastrostomy tube. Laparoscopic gastropexy can treat obstructed gastric volvulus in highoperative risk patients. Because of associated morbidity, gastrostomy tubes should be placed selectively. Copyright © 2015 Elsevier Inc. All rights reserved.

Electronic and mechanical characteristics of stacked dimer molecular junctions.

PubMed

Magyarkuti, András; Adak, Olgun; Halbritter, Andras; Venkataraman, Latha

2018-02-15

Break-junction measurements are typically aimed at characterizing electronic properties of single molecules bound between two metal electrodes. Although these measurements have provided structure-function relationships for such devices, there is little work that studies the impact of molecule-molecule interactions on junction characteristics. Here, we use a scanning tunneling microscope based break-junction technique to study pi-stacked dimer junctions formed with two amine-terminated conjugated molecules. We show that the conductance, force and flicker noise of such dimers differ dramatically when compared with the corresponding monomer junctions and discuss the implications of these results on intra- and inter-molecular charge transport.

Experiments and 3D simulations of flow structures in junctions and their influence on location of flowmeters.

PubMed

Mignot, E; Bonakdari, H; Knothe, P; Lipeme Kouyi, G; Bessette, A; Rivière, N; Bertrand-Krajewski, J-L

2012-01-01

Open-channel junctions are common occurrences in sewer networks and flow rate measurement often occurs near these singularities. Local flow structures are 3D, impact on the representativeness of the local flow measurements and thus lead to deviations in the flow rate estimation. The present study aims (i) to measure and simulate the flow pattern in a junction flow, (ii) to analyse the impact of the junction on the velocity distribution according to the distance from the junction and thus (iii) to evaluate the typical error derived from the computation of the flow rate close to the junction.

Current–phase relations of few-mode InAs nanowire Josephson junctions

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

Spanton, Eric M.; Deng, Mingtang; Vaitiekėnas, Saulius

Gate-tunable semiconductor nanowires with superconducting leads have great potential for quantum computation and as model systems for mesoscopic Josephson junctions. The supercurrent, I, versus the phase, Φ, across the junction is called the current–phase relation (CPR). It can reveal not only the amplitude of the critical current, but also the number of modes and their transmission. Here, we measured the CPR of many individual InAs nanowire Josephson junctions, one junction at a time. Both the amplitude and shape of the CPR varied between junctions, with small critical currents and skewed CPRs indicating few-mode junctions with high transmissions. In a gate-tunablemore » junction, we found that the CPR varied with gate voltage: near the onset of supercurrent, we observed behaviour consistent with resonant tunnelling through a single, highly transmitting mode. The gate dependence is consistent with modelled subband structure that includes an effective tunnelling barrier due to an abrupt change in the Fermi level at the boundary of the gate-tuned region. These measurements of skewed, tunable, few-mode CPRs are promising both for applications that require anharmonic junctions and for Majorana readout proposals.« less

Junction detection and pathway selection

NASA Astrophysics Data System (ADS)

Peck, Alex N.; Lim, Willie Y.; Breul, Harry T.

1992-02-01

The ability to detect junctions and make choices among the possible pathways is important for autonomous navigation. In our script-based navigation approach where a journey is specified as a script of high-level instructions, actions are frequently referenced to junctions, e.g., `turn left at the intersection.' In order for the robot to carry out these kind of instructions, it must be able (1) to detect an intersection (i.e., an intersection of pathways), (2) know that there are several possible pathways it can take, and (3) pick the pathway consistent with the high level instruction. In this paper we describe our implementation of the ability to detect junctions in an indoor environment, such as corners, T-junctions and intersections, using sonar. Our approach uses a combination of partial scan of the local environment and recognition of sonar signatures of certain features of the junctions. In the case where the environment is known, we use additional sensor information (such as compass bearings) to help recognize the specific junction. In general, once a junction is detected and its type known, the number of possible pathways can be deduced and the correct pathway selected. Then the appropriate behavior for negotiating the junction is activated.

Raising the one-sun conversion efficiency of III-V/Si solar cells to 32.8% for two junctions and 35.9% for three junctions

NASA Astrophysics Data System (ADS)

Essig, Stephanie; Allebé, Christophe; Remo, Timothy; Geisz, John F.; Steiner, Myles A.; Horowitz, Kelsey; Barraud, Loris; Ward, J. Scott; Schnabel, Manuel; Descoeudres, Antoine; Young, David L.; Woodhouse, Michael; Despeisse, Matthieu; Ballif, Christophe; Tamboli, Adele

2017-09-01

Today's dominant photovoltaic technologies rely on single-junction devices, which are approaching their practical efficiency limit of 25-27%. Therefore, researchers are increasingly turning to multi-junction devices, which consist of two or more stacked subcells, each absorbing a different part of the solar spectrum. Here, we show that dual-junction III-V//Sidevices with mechanically stacked, independently operated III-V and Si cells reach cumulative one-sun efficiencies up to 32.8%. Efficiencies up to 35.9% were achieved when combining a GaInP/GaAs dual-junction cell with a Si single-junction cell. These efficiencies exceed both the theoretical 29.4% efficiency limit of conventional Si technology and the efficiency of the record III-V dual-junction device (32.6%), highlighting the potential of Si-based multi-junction solar cells. However, techno-economic analysis reveals an order-of-magnitude disparity between the costs for III-V//Si tandem cells and conventional Si solar cells, which can be reduced if research advances in low-cost III-V growth techniques and new substrate materials are successful.

Current–phase relations of few-mode InAs nanowire Josephson junctions

DOE PAGES

Spanton, Eric M.; Deng, Mingtang; Vaitiekėnas, Saulius; ...

2017-08-14

Gate-tunable semiconductor nanowires with superconducting leads have great potential for quantum computation and as model systems for mesoscopic Josephson junctions. The supercurrent, I, versus the phase, Φ, across the junction is called the current–phase relation (CPR). It can reveal not only the amplitude of the critical current, but also the number of modes and their transmission. Here, we measured the CPR of many individual InAs nanowire Josephson junctions, one junction at a time. Both the amplitude and shape of the CPR varied between junctions, with small critical currents and skewed CPRs indicating few-mode junctions with high transmissions. In a gate-tunablemore » junction, we found that the CPR varied with gate voltage: near the onset of supercurrent, we observed behaviour consistent with resonant tunnelling through a single, highly transmitting mode. The gate dependence is consistent with modelled subband structure that includes an effective tunnelling barrier due to an abrupt change in the Fermi level at the boundary of the gate-tuned region. These measurements of skewed, tunable, few-mode CPRs are promising both for applications that require anharmonic junctions and for Majorana readout proposals.« less

Raising the one-sun conversion efficiency of III–V/Si solar cells to 32.8% for two junctions and 35.9% for three junctions

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

Essig, Stephanie; Allebé, Christophe; Remo, Timothy

Today's dominant photovoltaic technologies rely on single-junction devices, which are approaching their practical efficiency limit of 25-27%. Therefore, researchers are increasingly turning to multi-junction devices, which consist of two or more stacked subcells, each absorbing a different part of the solar spectrum. Here, we show that dual-junction III-V//Sidevices with mechanically stacked, independently operated III-V and Si cells reach cumulative one-sun efficiencies up to 32.8%. Efficiencies up to 35.9% were achieved when combining a GaInP/GaAs dual-junction cell with a Si single-junction cell. These efficiencies exceed both the theoretical 29.4% efficiency limit of conventional Si technology and the efficiency of the recordmore » III-V dual-junction device (32.6%), highlighting the potential of Si-based multi-junction solar cells. However, techno-economic analysis reveals an order-of-magnitude disparity between the costs for III-V//Si tandem cells and conventional Si solar cells, which can be reduced if research advances in low-cost III-V growth techniques and new substrate materials are successful.« less

Pulmonary distribution of an inhaled radioaerosol in obstructive pulmonary disease

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

Lin, M.S.; Goodwin, D.A.

1976-03-01

Pulmonary distribution of an inhaled radioaerosol was analyzed in 20 cases of chronic obstructive pulmonary disease (COPD) and 8 of other OPD. Nonciliary/ciliary partition of the distribution correlated with the severity of airway obstruction and approximated 3 : 1 in mild and 1 : 3 in very severe obstruction. In nuclear images, the distribution featured contrast abnormalities of hyperdeposition and hypodeposition. Intense hyperdeposition most commonly occurred in hilar and perihilar large airways. In isolated instances, hyperdeposition almost certainly occurred focally at sites of partial bronchial obstruction and diffusely by expiratory trapping; hypodeposition occurred distally to bronchial obstruction and in areasmore » of parenchymal loss. (auth)« less

Management of extremely low birth weight neonates with bowel obstruction within 2 weeks after birth.

PubMed

Hatanaka, Akira; Nakahara, Saori; Takeyama, Eriko; Iwanaka, Tadashi; Ishida, Kazuo

2014-12-01

The majority of bowel obstructions in extremely low birth weight (ELBW) neonates are meconium-related ileus (MRI). ELBW neonates with bowel obstruction may recover by conservative treatment, but some do not. Considering the high surgical morbidity rates, unnecessary surgery should be avoided. We sought to identify a reasonable treatment strategy under these conditions. ELBW neonates who started to have bowel obstruction with an unclear cause within 14 days of age were enrolled. The study period was from January 2009 to August 2011. The enrolled patients had daily Gastrografin(®) enemas until 14 days of age or until the obstruction resolved. If the obstruction lasted beyond around 14 days of age, the patient underwent surgical intervention. The clinical data of the patients were collected and analyzed. Fourteen patients were enrolled. Twelve patients had MRI, which resolved within 14 days without surgery. Two patients with persistent obstruction underwent surgery, and they were found to have Hirschsprung's disease and ileal volvulus, respectively. For ELBW neonates with bowel obstruction of unclear etiology, the early and frequent administration of a Gastrografin(®) enema is reasonable. Surgery should be considered if the obstruction lasts beyond approximately 14 days after birth.

33 CFR 64.31 - Determination of hazard to navigation.

Code of Federal Regulations, 2013 CFR

2013-07-01

... AIDS TO NAVIGATION MARKING OF STRUCTURES, SUNKEN VESSELS AND OTHER OBSTRUCTIONS Miscellaneous...) Location of the obstruction in relation to other obstructions or aids to navigation; (h) Prevailing and historical weather conditions; (i) Length of time that the obstruction has been in existence; (j) History of...

33 CFR 64.31 - Determination of hazard to navigation.

Code of Federal Regulations, 2014 CFR

2014-07-01

... AIDS TO NAVIGATION MARKING OF STRUCTURES, SUNKEN VESSELS AND OTHER OBSTRUCTIONS Miscellaneous...) Location of the obstruction in relation to other obstructions or aids to navigation; (h) Prevailing and historical weather conditions; (i) Length of time that the obstruction has been in existence; (j) History of...

33 CFR 64.31 - Determination of hazard to navigation.

Code of Federal Regulations, 2011 CFR

2011-07-01

... AIDS TO NAVIGATION MARKING OF STRUCTURES, SUNKEN VESSELS AND OTHER OBSTRUCTIONS Miscellaneous...) Location of the obstruction in relation to other obstructions or aids to navigation; (h) Prevailing and historical weather conditions; (i) Length of time that the obstruction has been in existence; (j) History of...

33 CFR 64.31 - Determination of hazard to navigation.

Code of Federal Regulations, 2012 CFR

2012-07-01

... AIDS TO NAVIGATION MARKING OF STRUCTURES, SUNKEN VESSELS AND OTHER OBSTRUCTIONS Miscellaneous...) Location of the obstruction in relation to other obstructions or aids to navigation; (h) Prevailing and historical weather conditions; (i) Length of time that the obstruction has been in existence; (j) History of...

33 CFR 64.31 - Determination of hazard to navigation.

Code of Federal Regulations, 2010 CFR

2010-07-01

... AIDS TO NAVIGATION MARKING OF STRUCTURES, SUNKEN VESSELS AND OTHER OBSTRUCTIONS Miscellaneous...) Location of the obstruction in relation to other obstructions or aids to navigation; (h) Prevailing and historical weather conditions; (i) Length of time that the obstruction has been in existence; (j) History of...

Precision measurement with an optical Josephson junction

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

Ng, H. T.; Burnett, K.; Dunningham, J. A.

2007-06-15

We present a theoretical study of a type of Josephson device, the so-called 'optical Josephson junction' [Y. Shin et al. Phys. Rev. Lett. 95, 170402 (2005).]. In this device, two condensates are optically coupled through a waveguide by a pair of Bragg beams. This optical Josephson junction differs from the usual Josephson junction where condensates are weakly coupled by tunneling through a barrier. We discuss the use of this optical Josephson junction, for making precision measurements.

Superconducting Quantum Interference Devices for the Detection of Magnetic Flux and Application to Airborne High Frequency Direction Finding

DTIC Science & Technology

2015-03-26

junction [29]. • The Resistively-Shunted- Junction (RSJ) Model • The Tunnel - Junction -Microscopic (TJM) Model • The Nonlinear...Resistive (RSJN) Model These circuit representations describe the junction using a parallel configuration of a resistor, noise current source, and a...solution for the Josephson junction IVP model equation for the noise -free case, in = 0. The thermal noise current is set to zero to exclude noise

Functional assessment of gap junctions in monolayer and three-dimensional cultures of human tendon cells using fluorescence recovery after photobleaching

PubMed Central

Kuzma-Kuzniarska, Maria; Yapp, Clarence; Pearson-Jones, Thomas W.; Jones, Andrew K.; Hulley, Philippa A.

2014-01-01

Abstract. Gap junction-mediated intercellular communication influences a variety of cellular activities. In tendons, gap junctions modulate collagen production, are involved in strain-induced cell death, and are involved in the response to mechanical stimulation. The aim of the present study was to investigate gap junction-mediated intercellular communication in healthy human tendon-derived cells using fluorescence recovery after photobleaching (FRAP). The FRAP is a noninvasive technique that allows quantitative measurement of gap junction function in living cells. It is based on diffusion-dependent redistribution of a gap junction-permeable fluorescent dye. Using FRAP, we showed that human tenocytes form functional gap junctions in monolayer and three-dimensional (3-D) collagen I culture. Fluorescently labeled tenocytes following photobleaching rapidly reacquired the fluorescent dye from neighboring cells, while HeLa cells, which do not communicate by gap junctions, remained bleached. Furthermore, both 18 β-glycyrrhetinic acid and carbenoxolone, standard inhibitors of gap junction activity, impaired fluorescence recovery in tendon cells. In both monolayer and 3-D cultures, intercellular communication in isolated cells was significantly decreased when compared with cells forming many cell-to-cell contacts. In this study, we used FRAP as a tool to quantify and experimentally manipulate the function of gap junctions in human tenocytes in both two-dimensional (2-D) and 3-D cultures. PMID:24390370

Ultra-Shallow Junctions Fabrication by Plasma Immersion Implantation on PULSION registered Followed by Laser Thermal Processing

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

Torregrosa, Frank; Etienne, Hasnaa; Sempere, Guillaume

In order to achieve the requirements for P+/N junctions for <45 nm ITRS nodes, ultra low energy and high dose implantations are needed. Classical beamline implantation is now limited in low energies, compared to Plasma Immersion Ion Implantation (PIII) which efficiency is no more to prove for the realization of Ultra-Shallow Junctions (USJ) in semiconductor applications : this technique allows to get ultimate shallow profiles (as implanted) due to no lower limitation of energy and high dose rate. Electrical activation is also a big issue since it has to afford high electrical activation rate with very low diffusion. Laser annealingmore » is one of the candidates for the 45 nm node. This paper presents electrical and physico-chemical characterizations of junctions realized with BF3 PIII followed by laser thermal processing with aim to obtain ultra-shallow junctions. Different implantation conditions (acceleration voltage/dose) and laser conditions (laser types, fluence/number of shots) are used for this study. Pre-amorphization is also used to confine the junction depth, and is shown to have a positive effect on junction depth but leads in higher junction leakage due to the remaining of EOR defects. The characterization is done using Optical characterization tool (SEMILAB) for sheet resistance and junction leakage measurements. SIMS is used for Boron profile and junction depth.« less

Transparent contacts for stacked compound photovoltaic cells

DOEpatents

Tauke-Pedretti, Anna; Cederberg, Jeffrey; Nielson, Gregory N.; Okandan, Murat; Cruz-Campa, Jose Luis

2016-11-29

A microsystems-enabled multi-junction photovoltaic (MEM-PV) cell includes a first photovoltaic cell having a first junction, the first photovoltaic cell including a first semiconductor material employed to form the first junction, the first semiconductor material having a first bandgap. The MEM-PV cell also includes a second photovoltaic cell comprising a second junction. The second photovoltaic cell comprises a second semiconductor material employed to form the second junction, the second semiconductor material having a second bandgap that is less than the first bandgap, the second photovoltaic cell further comprising a first contact layer disposed between the first junction of the first photovoltaic cell and the second junction of the second photovoltaic cell, the first contact layer composed of a third semiconductor material having a third bandgap, the third bandgap being greater than or equal to the first bandgap.

Fabrication and characterization of graphene/molecule/graphene vertical junctions with aryl alkane monolayers

NASA Astrophysics Data System (ADS)

Jeong, Inho; Song, Hyunwook

2017-11-01

In this study, we fabricated and characterized graphene/molecule/graphene (GMG) vertical junctions with aryl alkane monolayers. The constituent molecules were chemically self-assembled via electrophilic diazonium reactions into a monolayer on the graphene bottom electrode, while the other end physically contacted the graphene top electrode. A full understanding of the transport properties of molecular junctions is a key step in the realization of molecular-scale electronic devices and requires detailed microscopic characterization of the junction's active region. Using a multiprobe approach combining a variety of transport techniques, we elucidated the transport mechanisms and electronic structure of the GMG junctions, including temperature- and length-variable transport measurements, and transition voltage spectroscopy. These results provide criteria to establish a valid molecular junction and to determine the most probable transport characteristics of the GMG junctions.

Breaking into the epithelial apical–junctional complex — news from pathogen hackers

PubMed Central

Vogelmann, Roger; Amieva, Manuel R; Falkow, Stanley; Nelson, W James

2012-01-01

The epithelial apical–junctional complex is a key regulator of cellular functions. In addition, it is an important target for microbial pathogens that manipulate the cell to survive, proliferate and sometimes persist within a host. Out of a myriad of potential molecular targets, some bacterial and viral pathogens have selected a subset of protein targets at the apical–junctional complex of epithelial cells. Studying how microbes use these targets also teaches us about the inherent physiological properties of host molecules in the context of normal junctional structure and function. Thus, we have learned that three recently uncovered components of the apical–junctional complex of the Ig superfamily — junctional adhesion molecule, Nectin and the coxsackievirus and adenovirus receptor — are important regulators of junction structure and function and represent critical targets of microbial virulence gene products. PMID:15037310

Breaking into the epithelial apical-junctional complex--news from pathogen hackers.

PubMed

Vogelmann, Roger; Amieva, Manuel R; Falkow, Stanley; Nelson, W James

2004-02-01

The epithelial apical-junctional complex is a key regulator of cellular functions. In addition, it is an important target for microbial pathogens that manipulate the cell to survive, proliferate and sometimes persist within a host. Out of a myriad of potential molecular targets, some bacterial and viral pathogens have selected a subset of protein targets at the apical-junctional complex of epithelial cells. Studying how microbes use these targets also teaches us about the inherent physiological properties of host molecules in the context of normal junctional structure and function. Thus, we have learned that three recently uncovered components of the apical-junctional complex of the Ig superfamily--junctional adhesion molecule, Nectin and the coxsackievirus and adenovirus receptor--are important regulators of junction structure and function and represent critical targets of microbial virulence gene products.

Small Bowel Obstruction Due to Mochi (Rice Cake): A Case Report and Review of the Literature.

PubMed

Park, Daeho; Inoue, Kazuoki; Hamada, Toshihiro; Taniguchi, Shin-Ichi; Sato, Naoki; Koda, Masahiko

2018-03-01

A 66-year-old man presented at our emergency department with severe intermittent abdominal pain. His history revealed that he had eaten several mochi (rice cakes) without sufficiently chewing them before swallowing. Following computed tomography that showed a high value, he was diagnosed with an obstruction caused by mochi. Although mochi obstruction can sometimes improve with conservative treatment, this case required laparotomy. Medical literature in English on small bowel obstruction due to mochi is rare, but fortunately in this case we were able to collect complete laboratory and imaging data. Furthermore, due to the surgical findings, we could clearly diagnose the pathophysiology of mochi obstruction. Here we describe a case of small bowel obstruction due to mochi, and review the literature to determine the characteristics of intestinal obstruction caused by it.

Evolutionary dynamics and sites of illegitimate recombination revealed in the interspersion and sequence junctions of two nonhomologous satellite DNAs in cactophilic Drosophila species.

PubMed

Kuhn, G C S; Teo, C H; Schwarzacher, T; Heslop-Harrison, J S

2009-05-01

Satellite DNA (satDNA) is a major component of genomes but relatively little is known about the fine-scale organization of unrelated satDNAs residing at the same chromosome location, and the sequence structure and dynamics of satDNA junctions. We studied the organization and sequence junctions of two nonhomologous satDNAs, pBuM and DBC-150, in three species from the neotropical Drosophila buzzatii cluster (repleta group). In situ hybridization to microchromosomes, interphase nuclei and extended DNA fibers showed frequent interspersion of the two satellites in D. gouveai, D. antonietae and, to a lesser extent, D. seriema. We isolated by PCR six pBuM x DBC-150 junctions: four are exclusive to D. gouveai and two are exclusive to D. antonietae. The six junction breakpoints occur at different positions within monomers, suggesting independent origin. Four junctions showed abrupt transitions between the two satellites, whereas two junctions showed a distinct 10 bp tandem duplication before the junction. Unlike pBuM, DBC-150 junction repeats are more variable than randomly cloned monomers and showed diagnostic features in common to a 3-monomer higher-order repeat seen in the sister species D. serido. The high levels of interspersion between pBuM and DBC-150 repeats suggest extensive rearrangements between the two satellites, maybe favored by specific features of the microchromosomes. Our interpretation is that the junctions evolved by multiples events of illegitimate recombination between nonhomologous satDNA repeats, with subsequent rounds of unequal crossing-over expanding the copy number of some of the junctions.

Interferon-gamma inhibits intestinal restitution by preventing gap junction communication between enterocytes.

PubMed

Leaphart, Cynthia L; Qureshi, Faisal; Cetin, Selma; Li, Jun; Dubowski, Theresa; Baty, Catherine; Batey, Catherine; Beer-Stolz, Donna; Guo, Fengli; Murray, Sandra A; Hackam, David J

2007-06-01

Necrotizing enterocolitis (NEC) is characterized by interferon-gamma (IFN-gamma) release and inadequate intestinal restitution. Because enterocytes migrate together, mucosal healing may require interenterocyte communication via connexin 43-mediated gap junctions. We hypothesize that enterocyte migration requires interenterocyte communication, that IFN impairs migration by impairing connexin 43, and that impaired healing during NEC is associated with reduced gap junctions. NEC was induced in Swiss-Webster or IFN(-/-) mice, and restitution was determined in the presence of the gap junction inhibitor oleamide, or via time-lapse microscopy of IEC-6 cells. Connexin 43 expression, trafficking, and localization were detected in cultured or primary enterocytes or mouse or human intestine by confocal microscopy and (35)S-labeling, and gap junction communication was assessed using live microscopy with oleamide or connexin 43 siRNA. Enterocytes expressed connexin 43 in vitro and in vivo, and exchanged fluorescent dye via gap junctions. Gap junction inhibition significantly reduced enterocyte migration in vitro and in vivo. NEC was associated with IFN release and loss of enterocyte connexin 43 expression. IFN inhibited enterocyte migration by reducing gap junction communication through the dephosphorylation and internalization of connexin 43. Gap junction inhibition significantly increased NEC severity, whereas reversal of the inhibitory effects of IFN on gap junction communication restored enterocyte migration after IFN exposure. Strikingly, IFN(-/-) mice were protected from the development of NEC, and showed restored connexin 43 expression and intestinal restitution. IFN inhibits enterocyte migration by preventing interenterocyte gap junction communication. Connexin 43 loss may provide insights into the development of NEC, in which restitution is impaired.

Regulation of tight junction assembly and epithelial morphogenesis by the heat shock protein Apg-2

PubMed Central

Aijaz, Saima; Sanchez-Heras, Elena; Balda, Maria S; Matter, Karl

2007-01-01

Background Tight junctions are required for epithelial barrier formation and participate in the regulation of signalling mechanisms that control proliferation and differentiation. ZO-1 is a tight junction-associated adaptor protein that regulates gene expression, junction assembly and epithelial morphogenesis. We have previously demonstrated that the heat shock protein Apg-2 binds ZO-1 and thereby regulates its role in cell proliferation. Here, we addressed the question whether Apg-2 is also important for junction formation and epithelial morphogenesis. Results We demonstrate that depletion of Apg-2 by RNAi in MDCK cells did not prevent formation of functional tight junctions. Similar to ZO-1, however, reduced expression of Apg-2 retarded de novo junction assembly if analysed in a Ca-switch model. Formation of functional junctions, as monitored by measuring transepithelial electrical resistance, and recruitment of tight and adherens junction markers were retarded. If cultured in three dimensional extracellular matrix gels, Apg-2 depleted cells, as previously shown for ZO-1 depleted cells, did not form hollow polarised cysts but poorly organised, irregular structures. Conclusion Our data indicate that Apg-2 regulates junction assembly and is required for normal epithelial morphogenesis in a three-dimensional culture system, suggesting that Apg-2 is an important regulator of epithelial differentiation. As the observed phenotypes are similar to those previously described for ZO-1 depleted cells and depletion of Apg-2 retards junctional recruitment of ZO-1, regulation of ZO-1 is likely to be an important functional role for Apg-2 during epithelial differentiation. PMID:18028534

Regulation of tight junction assembly and epithelial morphogenesis by the heat shock protein Apg-2.

PubMed

Aijaz, Saima; Sanchez-Heras, Elena; Balda, Maria S; Matter, Karl

2007-11-20

Tight junctions are required for epithelial barrier formation and participate in the regulation of signalling mechanisms that control proliferation and differentiation. ZO-1 is a tight junction-associated adaptor protein that regulates gene expression, junction assembly and epithelial morphogenesis. We have previously demonstrated that the heat shock protein Apg-2 binds ZO-1 and thereby regulates its role in cell proliferation. Here, we addressed the question whether Apg-2 is also important for junction formation and epithelial morphogenesis. We demonstrate that depletion of Apg-2 by RNAi in MDCK cells did not prevent formation of functional tight junctions. Similar to ZO-1, however, reduced expression of Apg-2 retarded de novo junction assembly if analysed in a Ca-switch model. Formation of functional junctions, as monitored by measuring transepithelial electrical resistance, and recruitment of tight and adherens junction markers were retarded. If cultured in three dimensional extracellular matrix gels, Apg-2 depleted cells, as previously shown for ZO-1 depleted cells, did not form hollow polarised cysts but poorly organised, irregular structures. Our data indicate that Apg-2 regulates junction assembly and is required for normal epithelial morphogenesis in a three-dimensional culture system, suggesting that Apg-2 is an important regulator of epithelial differentiation. As the observed phenotypes are similar to those previously described for ZO-1 depleted cells and depletion of Apg-2 retards junctional recruitment of ZO-1, regulation of ZO-1 is likely to be an important functional role for Apg-2 during epithelial differentiation.

A Novel Approach to Brachycephalic Syndrome. 1. Evaluation of Anatomical Intranasal Airway Obstruction.

PubMed

Oechtering, Gerhard U; Pohl, Sabine; Schlueter, Claudia; Lippert, Johanna P; Alef, Michaele; Kiefer, Ingmar; Ludewig, Eberhard; Schuenemann, Riccarda

2016-02-01

To evaluate airway obstruction due to abnormal intranasal anatomy in 3 brachycephalic dog breeds using computed tomography and rhinoscopy. Prospective clinical study. A total of 132 brachycephalic dogs (66 Pugs, 55 French Bulldogs, and 11 English Bulldogs) with severe respiratory distress due to brachycephalic syndrome. Computed tomography and anterior and posterior rhinoscopy were performed to evaluate endonasal obstruction. All dogs had abnormal conchal growth that obstructed the intranasal airways. Rostral aberrant turbinates (RAT) were common in Pugs (90.9%) but less frequent in French (56.4%) and English (36.4%) Bulldogs. Caudal aberrant turbinates (CAT) obstructing the nasopharyngeal meatus were commonly found in all breeds (66.7%). Deviation of the nasal septum was an almost consistent finding in Pugs (98.5%) but was less common in bulldogs. Obstructing turbinates had multiple points of mucosal contact responsible for obstruction of the intranasal airway. Interconchal and intraconchal mucosal contacts were evident in 91.7% of dogs. Selective breeding for short head conformation reduces the size of the nasal cavities to such an extent that intranasal structures grow aberrantly and malformed, leading to obstructed air conducting spaces. Intranasal airway obstruction of brachycephalic dogs may contribute to their exercise and heat intolerance because of impaired pulmonary ventilation and compromised thermoregulatory functions of the canine nose. Failure to address intranasal obstruction might be an explanation for lack of therapeutic success after conventional surgery for brachycephalic syndrome. Future consideration should be given to the diagnosis, management, and treatment of this newly described aspect of airway obstruction. © Copyright 2016 by The American College of Veterinary Surgeons.

Comparison of radiography and ultrasonography for diagnosing small-intestinal mechanical obstruction in vomiting dogs.

PubMed

Sharma, Ajay; Thompson, Margret S; Scrivani, Peter V; Dykes, Nathan L; Yeager, Amy E; Freer, Sean R; Erb, Hollis N

2011-01-01

A cross-sectional study was performed on acutely vomiting dogs to compare the accuracy of radiography and ultrasonography for the diagnosis of small-intestinal mechanical obstruction and to describe several radiographic and ultrasonographic signs to identify their contribution to the final diagnosis. The sample population consisted of 82 adult dogs and small-intestinal obstruction by foreign body was confirmed in 27/82 (33%) dogs by surgery or necropsy. Radiography produced a definitive result (obstructed or not obstructed) in 58/82 (70%) of dogs; ultrasonography produced a definitive result in 80/82 (97%) of dogs. On radiographs, a diagnosis of obstruction was based on detection of segmental small-intestinal dilatation, plication, or detection of a foreign body. Approximately 30% (8/27) of obstructed dogs did not have radiographic signs of segmental small-intestinal dilatation, of which 50% (4/8) were due to linear foreign bodies. The ultrasonographic diagnosis of small-intestinal obstruction was based on detection of an obstructive lesion, sonographic signs of plication or segmental, small-intestinal dilatation. The ultrasonographic presence or absence of moderate-to-severe intestinal diameter enlargement (due to lumen dilatation) of the jejunum (>1.5 cm) was a useful discriminatory finding and, when present, should prompt a thorough search for a cause of small-intestinal obstruction. In conclusion, both abdominal radiography and abdominal ultrasonography are accurate for diagnosing small-intestinal obstruction in vomiting dogs and either may be used depending on availability and examiner choice. Abdominal ultrasonography had greater accuracy, fewer equivocal results and provided greater diagnostic confidence compared with radiography. © 2010 Veterinary Radiology & Ultrasound.

Radiofrequency tissue ablation of the inferior turbinates using a thermocouple feedback electrode.

PubMed

Smith, T L; Correa, A J; Kuo, T; Reinisch, L

1999-11-01

The objective of this clinical trial was to assess the safety and efficacy of radiofrequency (RF) tissue ablation of the inferior turbinates in the treatment of nasal obstruction using an RF energy delivery system with a thermocouple feedback electrode. A prospective, nonrandomized study of 11 patients (mean age, 47+/-12 y) with chronic nasal obstruction was conducted. Using patient-based visual analogue scales (VAS), symptom parameters were assessed. These included degree of nasal obstruction, frequency of nasal obstruction, and pain. Physician assessment of nasal obstruction was also collected by the principal investigator. Follow-up was conducted at 24 hours, 1 week, 4 weeks, 8 weeks, and 1 year. ANOVA was carried out to determine statistically significant differences in the data. Data were fit to a regression model, and confidence intervals were determined from a 95% confidence level. In patient-assessed degree of nasal obstruction, statistical significance was seen among baseline and 4 weeks, 8 weeks, and 1 year (P<.001, P<.0001, and P<.0008, respectively). There was no difference between 8 weeks and 1 year (P<.15). The data appeared to follow an exponential decay to a constant value. The pretreatment baseline average degree of obstruction was 7.5+/-0.5 on a scale of 0 to 10. The degree of obstruction after 8 weeks was 2.7+/-0.6. The time constant for this change was 21 days to reach 90% of the final value. At 1 year, degree of obstruction was 3.3+/-0.7. For frequency of nasal obstruction, statistical significance was seen among baseline and 4 weeks, 8 weeks, and 1 year (P<.0001, P<.0001, and P<.0001, respectively). There was no difference between 8 weeks and 1 year (P<.15). The pretreatment baseline average frequency of obstruction was 7.8+/-0.5. The remaining frequency of obstruction after 8 weeks was 2.9+/-0.6. The time constant was 18 days. At 1 year, frequency of obstruction was 3.3+/-0.6. Physician assessment of nasal obstruction revealed statistical significance among baseline and 4 weeks, and baseline and 8 weeks (P<.0055 and P<.0056, respectively). There was no difference between 4 weeks and 8 weeks (P<.24). The average initial obstruction was 83%+/-4%. The remaining obstruction after 8 weeks was 58% +/-5%. The time constant was 14 days. Mild pain was reported by 55% of patients during the procedure; the remaining 45% reported no pain. Only one patient required pain medication consisting of acetaminophen after the procedure. There were no significant complications. Degree and frequency of nasal obstruction, as reported by patients, decreased following RF tissue ablation of the inferior turbinates. This improvement in symptoms was still evident after 1 year (P<.001). Physician assessment of obstruction also correlated with patient reports for the initial 8-week study period. The procedure was safe and well tolerated. Thermocouples within the active electrode provided additional feedback to the operating surgeon allowing the use of relatively lower tissue temperatures, power, and energy as compared with traditional techniques. These results support the need for continued research to evaluate this modality as a treatment for chronic nasal obstruction.

30 CFR 75.602 - Trailing cable junctions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Trailing cable junctions. 75.602 Section 75.602... MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Trailing Cables § 75.602 Trailing cable junctions. [Statutory Provision] When two or more trailing cables junction to the same distribution center, means shall...

Public Health Nursing: Public Health Centers

Science.gov Websites

Locations Anchorage-based Itinerants Bethel Craig Delta Junction Dillingham Fairbanks Homer Juneau Kenai agencies with state grant assistance Frontier Region Delta Junction Dillingham Fairbanks Kodiak Nome Tok [back to top] Delta Junction Public Health Center 2857 Alaska Hwy, Room 210 Delta Junction, Alaska 99737

Amorphous semiconductor solar cell

DOEpatents

Dalal, Vikram L.

1981-01-01

A solar cell comprising a back electrical contact, amorphous silicon semiconductor base and junction layers and a top electrical contact includes in its manufacture the step of heat treating the physical junction between the base layer and junction layer to diffuse the dopant species at the physical junction into the base layer.

Model Building to Facilitate Understanding of Holliday Junction and Heteroduplex Formation, and Holliday Junction Resolution

ERIC Educational Resources Information Center

Selvarajah, Geeta; Selvarajah, Susila

2016-01-01

Students frequently expressed difficulty in understanding the molecular mechanisms involved in chromosomal recombination. Therefore, we explored alternative methods for presenting the two concepts of the double-strand break model: Holliday junction and heteroduplex formation, and Holliday junction resolution. In addition to a lecture and…

Using the Pathophysiology of Obstructive Sleep Apnea to Teach Cardiopulmonary Integration

ERIC Educational Resources Information Center

Levitzky, Michael G.

2008-01-01

Obstructive sleep apnea (OSA) is a common disorder of upper airway obstruction during sleep. The effects of intermittent upper airway obstruction include alveolar hypoventilation, altered arterial blood gases and acid-base status, and stimulation of the arterial chemoreceptors, which leads to frequent arousals. These arousals disturb sleep…

33 CFR 67.05-5 - Multiple obstruction lights.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Multiple obstruction lights. 67... for Lights § 67.05-5 Multiple obstruction lights. When more than one obstruction light is required by this part to mark a structure, all such lights shall be operated to flash in unison. ...

33 CFR 67.05-5 - Multiple obstruction lights.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Multiple obstruction lights. 67... for Lights § 67.05-5 Multiple obstruction lights. When more than one obstruction light is required by this part to mark a structure, all such lights shall be operated to flash in unison. ...

33 CFR 67.05-5 - Multiple obstruction lights.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Multiple obstruction lights. 67... for Lights § 67.05-5 Multiple obstruction lights. When more than one obstruction light is required by this part to mark a structure, all such lights shall be operated to flash in unison. ...

33 CFR 67.05-5 - Multiple obstruction lights.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Multiple obstruction lights. 67... for Lights § 67.05-5 Multiple obstruction lights. When more than one obstruction light is required by this part to mark a structure, all such lights shall be operated to flash in unison. ...

33 CFR 67.05-5 - Multiple obstruction lights.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Multiple obstruction lights. 67... for Lights § 67.05-5 Multiple obstruction lights. When more than one obstruction light is required by this part to mark a structure, all such lights shall be operated to flash in unison. ...

An induced junction photovoltaic cell

NASA Technical Reports Server (NTRS)

Call, R. L.

1974-01-01

Silicon solar cells operating with induced junctions rather than diffused junctions have been fabricated and tested. Induced junctions were created by forming an inversion layer near the surface of the silicon by supplying a sheet of positive charge above the surface. Measurements of the response of the inversion layer cell to light of different wavelengths indicated it to be more sensitive to the shorter wavelengths of the sun's spectrum than conventional cells. The greater sensitivity occurs because of the shallow junction and the strong electric field at the surface.

Nondestructive determination of the depth of planar p-n junctions by scanning electron microscopy

NASA Technical Reports Server (NTRS)

Chi, J.-Y.; Gatos, H. C.

1977-01-01

A method was developed for measuring nondestructively the depth of planar p-n junctions in simple devices as well as in integrated-circuit structures with the electron-beam induced current (EBIC) by scanning parallel to the junction in a scanning electron microscope (SEM). The results were found to be in good agreement with those obtained by the commonly used destructive method of lapping at an angle to the junction and staining to reveal the junction.

Zero energy states at a normal-metal/cuprate-superconductor interface probed by shot noise

NASA Astrophysics Data System (ADS)

Negri, O.; Zaberchik, M.; Drachuck, G.; Keren, A.; Reznikov, M.

2018-06-01

We report measurements of the current noise generated in the optimally doped, x =0.15 , Au-La2-xSrxCuO4 junctions. For high transmission junctions on a (110) surface, we observed a split zero-bias conductance peak (ZBCP), accompanied by enhanced shot noise. We observed no enhanced noise neither in low-transmission junctions on a (110) surface nor in any junction on a (100) surface. We attribute the enhanced noise to Cooper pair transport through the junctions.

Structure of junctions of multiwalled carbon nanotubes with tetragonal cross section and flattened nanotubes revealed by electron-beam tomography

NASA Astrophysics Data System (ADS)

Nagano, Yuta; Kohno, Hideo

2017-11-01

Multiwalled carbon nanotubes with tetragonal cross section frequently form junctions with flattened multi-walled carbon nanotubes, a kind of carbon nanoribbon. The three-dimensional structure of the junctions is revealed by transmission-electron-microscopy-based tomography. Two types of junction, parallel and diagonal, are found. The formation mechanism of these two types of junction is discussed in terms of the origami mechanism that was previously proposed to explain the formation of carbon nanoribbons and nanotetrahedra.

Transmembrane proteins of tight junctions.

PubMed

Chiba, Hideki; Osanai, Makoto; Murata, Masaki; Kojima, Takashi; Sawada, Norimasa

2008-03-01

Tight junctions contribute to the paracellular barrier, the fence dividing plasma membranes, and signal transduction, acting as a multifunctional complex in vertebrate epithelial and endothelial cells. The identification and characterization of the transmembrane proteins of tight junctions, claudins, junctional adhesion molecules (JAMs), occludin and tricellulin, have led to insights into the molecular nature of tight junctions. We provide an overview of recent progress in studies on these proteins and highlight their roles and regulation, as well as their functional significance in human diseases.

Overdamped Nb/Al-AlO{sub x}/Nb Josephson junctions

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

Lacquaniti, V.; Cagliero, C.; Maggi, S.

2005-01-24

We report the fabrication and characterization of overdamped Nb/Al-AlO{sub x}/Nb superconductor-insulator-superconductor Josephson junction whose fabrication process derives from that of the well-known hysteretic junctions. These junctions are an intermediate state between the superconductor-normal metal-superconductor and the superconductor-insulator-superconductor Josephson junctions. Stable and reproducible nonhysteretic current-voltage characteristics are obtained with a proper choice of the fabrication parameters. We have measured critical current densities J{sub C} from 10{sup 3} up to 2x10{sup 4} A/cm{sup 2}, with characteristic voltages from 80 to nearly 450 {mu}V. The junctions are stable against time and repeated thermal cycling.

Cleavage of transmembrane junction proteins and their role in regulating epithelial homeostasis

PubMed Central

Nava, Porfirio; Kamekura, Ryuta; Nusrat, Asma

2013-01-01

Epithelial tissues form a selective barrier that separates the external environment from the internal tissue milieu. Single epithelial cells are densely packed and associate via distinct intercellular junctions. Intercellular junction proteins not only control barrier properties of the epithelium but also play an important role in regulating epithelial homeostasis that encompasses cell proliferation, migration, differentiation and regulated shedding. Recent studies have revealed that several proteases target epithelial junction proteins during physiological maturation as well as in pathologic states such as inflammation and cancer. This review discusses mechanisms and biological consequences of transmembrane junction protein cleavage. The influence of junction protein cleavage products on pathogenesis of inflammation and cancer is discussed. PMID:24665393

Macroscopic Quantum Tunneling in Superconducting Junctions of β-Ag2Se Topological Insulator Nanowire.

PubMed

Kim, Jihwan; Kim, Bum-Kyu; Kim, Hong-Seok; Hwang, Ahreum; Kim, Bongsoo; Doh, Yong-Joo

2017-11-08

We report on the fabrication and electrical transport properties of superconducting junctions made of β-Ag 2 Se topological insulator (TI) nanowires in contact with Al superconducting electrodes. The temperature dependence of the critical current indicates that the superconducting junction belongs to a short and diffusive junction regime. As a characteristic feature of the narrow junction, the critical current decreases monotonously with increasing magnetic field. The stochastic distribution of the switching current exhibits the macroscopic quantum tunneling behavior, which is robust up to T = 0.8 K. Our observations indicate that the TI nanowire-based Josephson junctions can be a promising building block for the development of nanohybrid superconducting quantum bits.

Performance of all-NbN superconductive tunnel junctions as mixers at 205 GHz

NASA Technical Reports Server (NTRS)

Mcgrath, W. R.; Leduc, H. G.; Stern, J. A.

1990-01-01

Small-area (1x1 sq micron) high-current-density NbN-MgO-NbN tunnel junctions with I-V characteristics suitable for high frequency mixers were fabricated. These junctions are integrated with superconducting microstrip lines designed to resonate out the large junction capacitance. The mixer gain and noise performance were studied near 205 GHz as a function of the inductance provided by the microstrip. This has yielded values of junction capacitance of 85 fF/sq microns and magnetic penetration depth of 3800 angstroms. Mixer noise as low as 133 K has been obtained for properly tuned junctions. This is the best noise performance ever reported for an NbN SIS mixer.

Fabrication of Josephson Junction without shadow evaporation

NASA Astrophysics Data System (ADS)

Wu, Xian; Ku, Hsiangsheng; Long, Junling; Pappas, David

We developed a new method of fabricating Josephson Junction (Al/AlOX/Al) without shadow evaporation. Statistics from room temperature junction resistance and measurement of qubits are presented. Unlike the traditional ``Dolan Bridge'' technique, this method requires two individual lithographies and straight evaporations of Al. Argon RF plasma is used to remove native AlOX after the first evaporation, followed by oxidation and second Al evaporation. Junction resistance measured at room temperature shows linear dependence on Pox (oxidation pressure), √{tox} (oxidation time), and inverse proportional to junction area. We have seen 100% yield of qubits made with this method. This method is promising because it eliminates angle dependence during Junction fabrication, facilitates large scale qubits fabrication.

Overlap junctions for high coherence superconducting qubits

NASA Astrophysics Data System (ADS)

Wu, X.; Long, J. L.; Ku, H. S.; Lake, R. E.; Bal, M.; Pappas, D. P.

2017-07-01

Fabrication of sub-micron Josephson junctions is demonstrated using standard processing techniques for high-coherence, superconducting qubits. These junctions are made in two separate lithography steps with normal-angle evaporation. Most significantly, this work demonstrates that it is possible to achieve high coherence with junctions formed on aluminum surfaces cleaned in situ by Ar plasma before junction oxidation. This method eliminates the angle-dependent shadow masks typically used for small junctions. Therefore, this is conducive to the implementation of typical methods for improving margins and yield using conventional CMOS processing. The current method uses electron-beam lithography and an additive process to define the top and bottom electrodes. Extension of this work to optical lithography and subtractive processes is discussed.

Obstructive ureteropathy following radiation therapy for carcinoma of the cervix

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

Parliament, M.; Genest, P.; Girard, A.

1989-05-01

Between January 1959 and December 1986, 10 of 328 patients (3%) treated with curative intent using primary radiation therapy for carcinoma of the cervix developed obstructive ureteropathy due to fibrosis. The mean age of the patients with obstructive ureteropathy was 45 years and the median time to obstruction was 26 months. The obstruction was unilateral in 8 cases and involved the parametrial portion of the ureter in at least 5 cases. No predisposing risk factor was found to be associated with the development of obstructive ureteropathy. After corrective surgery, renal function remained normal in 8 patients, and resolution of themore » hydronephrosis occurred in 4 patients.« less

Intestinal epithelial barrier function and tight junction proteins with heat and exercise

PubMed Central

Zuhl, Micah N.; Moseley, Pope L.

2015-01-01

A single layer of enterocytes and tight junctions (intercellular multiprotein complexes) form the intestinal epithelial barrier that controls transport of molecules through transcellular and paracellular pathways. A dysfunctional or “leaky” intestinal tight junction barrier allows augmented permeation of luminal antigens, endotoxins, and bacteria into the blood stream. Various substances and conditions have been shown to affect the maintenance of the intestinal epithelial tight junction barrier. The primary focus of the present review is to analyze the effects of exertional or nonexertional (passive hyperthermia) heat stress on tight junction barrier function in in vitro and in vivo (animals and humans) models. Our secondary focus is to review changes in tight junction proteins in response to exercise or hyperthermic conditions. Finally, we discuss some pharmacological or nutritional interventions that may affect the cellular mechanisms involved in maintaining homeostasis of the intestinal epithelial tight junction barrier during heat stress or exercise. PMID:26359485

Neogenin recruitment of the WAVE regulatory complex maintains adherens junction stability and tension

PubMed Central

Lee, Natalie K.; Fok, Ka Wai; White, Amanda; Wilson, Nicole H.; O'Leary, Conor J.; Cox, Hayley L.; Michael, Magdalene; Yap, Alpha S.; Cooper, Helen M.

2016-01-01

To maintain tissue integrity during epithelial morphogenesis, adherens junctions (AJs) must resist the mechanical stresses exerted by dynamic tissue movements. Junctional stability is dependent on actomyosin contractility within the actin ring. Here we describe a novel function for the axon guidance receptor, Neogenin, as a key component of the actin nucleation machinery governing junctional stability. Loss of Neogenin perturbs AJs and attenuates junctional tension. Neogenin promotes actin nucleation at AJs by recruiting the Wave regulatory complex (WRC) and Arp2/3. A direct interaction between the Neogenin WIRS domain and the WRC is crucial for the spatially restricted recruitment of the WRC to the junction. Thus, we provide the first example of a functional WIRS–WRC interaction in epithelia. We further show that Neogenin regulates cadherin recycling at the AJ. In summary, we identify Neogenin as a pivotal component of the AJ, where it influences both cadherin dynamics and junctional tension. PMID:27029596

Intestinal epithelial barrier function and tight junction proteins with heat and exercise.

PubMed

Dokladny, Karol; Zuhl, Micah N; Moseley, Pope L

2016-03-15

A single layer of enterocytes and tight junctions (intercellular multiprotein complexes) form the intestinal epithelial barrier that controls transport of molecules through transcellular and paracellular pathways. A dysfunctional or "leaky" intestinal tight junction barrier allows augmented permeation of luminal antigens, endotoxins, and bacteria into the blood stream. Various substances and conditions have been shown to affect the maintenance of the intestinal epithelial tight junction barrier. The primary focus of the present review is to analyze the effects of exertional or nonexertional (passive hyperthermia) heat stress on tight junction barrier function in in vitro and in vivo (animals and humans) models. Our secondary focus is to review changes in tight junction proteins in response to exercise or hyperthermic conditions. Finally, we discuss some pharmacological or nutritional interventions that may affect the cellular mechanisms involved in maintaining homeostasis of the intestinal epithelial tight junction barrier during heat stress or exercise. Copyright © 2016 the American Physiological Society.

Shot noise generated by graphene p–n junctions in the quantum Hall effect regime

PubMed Central

Kumada, N.; Parmentier, F. D.; Hibino, H.; Glattli, D. C.; Roulleau, P.

2015-01-01

Graphene offers a unique system to investigate transport of Dirac Fermions at p–n junctions. In a magnetic field, combination of quantum Hall physics and the characteristic transport across p–n junctions leads to a fractionally quantized conductance associated with the mixing of electron-like and hole-like modes and their subsequent partitioning. The mixing and partitioning suggest that a p–n junction could be used as an electronic beam splitter. Here we report the shot noise study of the mode-mixing process and demonstrate the crucial role of the p–n junction length. For short p–n junctions, the amplitude of the noise is consistent with an electronic beam-splitter behaviour, whereas, for longer p–n junctions, it is reduced by the energy relaxation. Remarkably, the relaxation length is much larger than typical size of mesoscopic devices, encouraging using graphene for electron quantum optics and quantum information processing. PMID:26337067

Highly-Sensitive Thin Film THz Detector Based on Edge Metal-Semiconductor-Metal Junction.

PubMed

Jeon, Youngeun; Jung, Sungchul; Jin, Hanbyul; Mo, Kyuhyung; Kim, Kyung Rok; Park, Wook-Ki; Han, Seong-Tae; Park, Kibog

2017-12-04

Terahertz (THz) detectors have been extensively studied for various applications such as security, wireless communication, and medical imaging. In case of metal-insulator-metal (MIM) tunnel junction THz detector, a small junction area is desirable because the detector response time can be shortened by reducing it. An edge metal-semiconductor-metal (EMSM) junction has been developed with a small junction area controlled precisely by the thicknesses of metal and semiconductor films. The voltage response of the EMSM THz detector shows the clear dependence on the polarization angle of incident THz wave and the responsivity is found to be very high (~2,169 V/W) at 0.4 THz without any antenna and signal amplifier. The EMSM junction structure can be a new and efficient way of fabricating the nonlinear device THz detector with high cut-off frequency relying on extremely small junction area.

Single-contact tunneling thermometry

DOEpatents

Maksymovych, Petro

2016-02-23

A single-contact tunneling thermometry circuit includes a tunnel junction formed between two objects. Junction temperature gradient information is determined based on a mathematical relationship between a target alternating voltage applied across the junction and the junction temperature gradient. Total voltage measured across the junction indicates the magnitude of the target alternating voltage. A thermal gradient is induced across the junction. A reference thermovoltage is measured when zero alternating voltage is applied across the junction. An increasing alternating voltage is applied while measuring a thermovoltage component and a DC rectification voltage component created by the applied alternating voltage. The target alternating voltage is reached when the thermovoltage is nullified or doubled by the DC rectification voltage depending on the sign of the reference thermovoltage. Thermoelectric current and current measurements may be utilized in place of the thermovoltage and voltage measurements. The system may be automated with a feedback loop.

Single-molecule detection of dihydroazulene photo-thermal reaction using break junction technique

NASA Astrophysics Data System (ADS)

Huang, Cancan; Jevric, Martyn; Borges, Anders; Olsen, Stine T.; Hamill, Joseph M.; Zheng, Jue-Ting; Yang, Yang; Rudnev, Alexander; Baghernejad, Masoud; Broekmann, Peter; Petersen, Anne Ugleholdt; Wandlowski, Thomas; Mikkelsen, Kurt V.; Solomon, Gemma C.; Brøndsted Nielsen, Mogens; Hong, Wenjing

2017-05-01

Charge transport by tunnelling is one of the most ubiquitous elementary processes in nature. Small structural changes in a molecular junction can lead to significant difference in the single-molecule electronic properties, offering a tremendous opportunity to examine a reaction on the single-molecule scale by monitoring the conductance changes. Here, we explore the potential of the single-molecule break junction technique in the detection of photo-thermal reaction processes of a photochromic dihydroazulene/vinylheptafulvene system. Statistical analysis of the break junction experiments provides a quantitative approach for probing the reaction kinetics and reversibility, including the occurrence of isomerization during the reaction. The product ratios observed when switching the system in the junction does not follow those observed in solution studies (both experiment and theory), suggesting that the junction environment was perturbing the process significantly. This study opens the possibility of using nano-structured environments like molecular junctions to tailor product ratios in chemical reactions.

Properties of Josephson Junction Fabricated on Bicrystal Substrate with Different Misorientation Angles

NASA Astrophysics Data System (ADS)

Minotani, Tadashi; Kawakami, Satoru; Kuroki, Yukinori; Enpuku, Keiji

1998-06-01

In order to develop YBa2Cu3O7-δ bicrystal junctions suitable for high-performance superconducting quantum interference device (SQUID), the relationship between the junction properties and the misorientation angle of the bicrystal substrate is studied experimentally. Misorientation angles of 24°, 27°, 30°, 33° and 36.8° are used, and the angular dependencies of junction resistance Rs and critical current Io are investigated. It is shown that values of Rs and Io approximately follow the relation IoRs1.5=const. in these junctions. The obtained results are analyzed in terms of the direct and resonant tunneling mechanisms. It is also shown that values of Rs≈10 Ω and Io≈20 µA can be obtained rather reproducibly when we use the 30° junctions. The properties of this junction are very promising for the development of high-performance SQUID.

Obstructive sleep apnea among commercial motor vehicle drivers: using evidence-based practice to identify risk factors.

PubMed

Olszewski, Kimberly; Wolf, Debra

2013-11-01

Commercial motor vehicle driving is a hazardous occupation, having the third highest fatality rate among common U.S. jobs. Among the estimated 14 million U.S. commercial motor vehicle drivers, the prevalence of obstructive sleep apnea is reported to be 17% to 28%. Despite the identified increased prevalence of obstructive sleep apnea among commercial motor vehicle drivers, federal law does not require that they be screened for obstructive sleep apnea. This article presents an evidence-based practice change project; the authors developed, implemented, and evaluated a screening program to identify commercial motor vehicle drivers' risk for obstructive sleep apnea during commercial driver medical examinations. The results of this practice change indicated screening for obstructive sleep apnea during the commercial driver medical examination led to improved identification of obstructive sleep apnea risk among commercial motor vehicle drivers and should be a clinical standard in occupational health clinics. Copyright 2013, SLACK Incorporated.

Drug-induced sleep endoscopy in the identification of obstruction sites in patients with obstructive sleep apnea: a systematic review.

PubMed

Viana, Alonço da Cunha; Thuler, Luiz Claudio Santos; Araújo-Melo, Maria Helena de

2015-01-01

Obstructive sleep apnea syndrome has multifactorial causes. Although indications for surgery are evaluated by well-known diagnostic tests in the awake state, these do not always correlate with satisfactory surgical results. To undertake a systematic review on endoscopy during sleep, as one element of the diagnosis routine, aiming to identify upper airway obstruction sites in adult patients with OSAS. By means of electronic databases, a systematic review was performed of studies using drug-induced sleep endoscopy to identify obstruction sites in patients with OSAS. Ten articles were selected that demonstrated the importance of identifying multilevel obstruction, especially in relation to retrolingual and laryngeal collapse in OSAS. DISE is an additional method to reveal obstruction sites that have not been detected in awake patients. Copyright © 2015 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Extrahepatic portal vein obstruction and portal vein thrombosis in special situations: Need for a new classification.

PubMed

Wani, Zeeshan A; Bhat, Riyaz A; Bhadoria, Ajeet S; Maiwall, Rakhi

2015-01-01

Extrahepatic portal vein obstruction is a vascular disorder of liver, which results in obstruction and cavernomatous transformation of portal vein with or without the involvement of intrahepatic portal vein, splenic vein, or superior mesenteric vein. Portal vein obstruction due to chronic liver disease, neoplasm, or postsurgery is a separate entity and is not the same as extrahepatic portal vein obstruction. Patients with extrahepatic portal vein obstruction are generally young and belong mostly to Asian countries. It is therefore very important to define portal vein thrombosis as acute or chronic from management point of view. Portal vein thrombosis in certain situations such as liver transplant and postsurgical/liver transplant period is an evolving area and needs extensive research. There is a need for a new classification, which includes all areas of the entity. In the current review, the most recent literature of extrahepatic portal vein obstruction is reviewed and summarized.

Ventilation inhomogeneity in obstructive lung diseases measured by electrical impedance tomography: a simulation study.

PubMed

Schullcke, B; Krueger-Ziolek, S; Gong, B; Jörres, R A; Mueller-Lisse, U; Moeller, K

2017-10-10

Electrical impedance tomography (EIT) has mostly been used in the Intensive Care Unit (ICU) to monitor ventilation distribution but is also promising for the diagnosis in spontaneously breathing patients with obstructive lung diseases. Beside tomographic images, several numerical measures have been proposed to quantitatively assess the lung state. In this study two common measures, the 'Global Inhomogeneity Index' and the 'Coefficient of Variation' were compared regarding their capability to reflect the severity of lung obstruction. A three-dimensional simulation model was used to simulate obstructed lungs, whereby images were reconstructed on a two-dimensional domain. Simulations revealed that minor obstructions are not adequately recognized in the reconstructed images and that obstruction above and below the electrode plane may result in misleading values of inhomogeneity measures. EIT measurements on several electrode planes are necessary to apply these measures in patients with obstructive lung diseases in a promising manner.

Extrahepatic Portal Vein Obstruction and Portal Vein Thrombosis in Special Situations: Need for a New Classification

PubMed Central

Wani, Zeeshan A.; Bhat, Riyaz A.; Bhadoria, Ajeet S.; Maiwall, Rakhi

2015-01-01

Extrahepatic portal vein obstruction is a vascular disorder of liver, which results in obstruction and cavernomatous transformation of portal vein with or without the involvement of intrahepatic portal vein, splenic vein, or superior mesenteric vein. Portal vein obstruction due to chronic liver disease, neoplasm, or postsurgery is a separate entity and is not the same as extrahepatic portal vein obstruction. Patients with extrahepatic portal vein obstruction are generally young and belong mostly to Asian countries. It is therefore very important to define portal vein thrombosis as acute or chronic from management point of view. Portal vein thrombosis in certain situations such as liver transplant and postsurgical/liver transplant period is an evolving area and needs extensive research. There is a need for a new classification, which includes all areas of the entity. In the current review, the most recent literature of extrahepatic portal vein obstruction is reviewed and summarized. PMID:26021771

Removal of obstructing T-tube and stabilization of the airway.

PubMed

Athavale, Sanjay M; Dang, Jennifer; Rangarajan, Sanjeet; Garrett, Gaelyn

2011-05-01

Although they are extremely effective in maintaining tracheal and subglottic patency, T-tubes themselves can result in airway obstruction from plugging. Many practitioners educate patients on placing a small (5.0) endotracheal tube (ETT) through the tracheal limb of the T-tube if they develop airway obstruction. Unfortunately, this can be a difficult task to complete during acute airway obstruction. In this article, we describe a simple set of steps for rapid relief of airway obstruction and stabilization of the airway in the event of T-tube obstruction. This method requires removal of the T-tube with a Kelly clamp and stabilization of the airway with a tracheostomy tube. Although it is simple, we hope that this technique will prevent morbidity and mortality from acute airway obstructions related to T-tubes. Copyright © 2011 The American Laryngological, Rhinological, and Otological Society, Inc.

Self-Contained Compressed-Flow Generation Device for Use in Making Differential Measurements

NASA Technical Reports Server (NTRS)

England, John Dwight (Inventor); Kelley, Anthony R. (Inventor); Cronise, Raymond J. (Inventor)

2014-01-01

A device used in making differential measurements of a flow includes a flow obstruction and a support arm. The flow obstruction's forward portion is a nose cone. The flow obstruction's aft portion is coupled to the nose cone. The support arm's first end is coupled to an exterior wall of a conduit, and its second end is coupled to the forward portion of the flow obstruction. The support arm positions the flow obstruction in the conduit such that a flow region is defined around its nose cone, and such that the support arm's first and second end are separated from one another with respect to a length dimension of the conduit. Measurement ports are provided in the support arm and flow obstruction. Manifolds extending through the flow obstruction and support arm couple the ports to points at the exterior wall of the conduit.

All NbN tunnel junction fabrication

NASA Technical Reports Server (NTRS)

Leduc, H. G.; Khanna, S. K.; Stern, J. A.

1987-01-01

The development of SIS tunnel junctions based on NbN for mixer applications in the submillimeter range is reported. The unique technological challenges inherent in the development of all refractory-compound superconductor-based tunnel junctions are highlighted. Current deposition and fabrication techniques are discussed, and the current status of all-NbN tunnel junctions is reported.

Design and optimization of ARC less InGaP/GaAs single-/multi-junction solar cells with tunnel junction and back surface field layers

NASA Astrophysics Data System (ADS)

Chee, Kuan W. A.; Hu, Yuning

2018-07-01

There has always been an inexorable interest in the solar industry in boosting the photovoltaic conversion efficiency. This paper presents a theoretical and numerical simulation study of the effects of key design parameters on the photoelectric performance of single junction (InGaP- or GaAs-based) and dual junction (InGaP/GaAs) inorganic solar cells. The influence of base layer thickness, base doping concentration, junction temperature, back surface field layer composition and thickness, and tunnel junction material, were correlated with open circuit voltage, short-circuit current, fill factor and power conversion efficiency performance. The InGaP/GaAs dual junction solar cell was optimized with the tunnel junction and back surface field designs, yielding a short-circuit current density of 20.71 mAcm-2 , open-circuit voltage of 2.44 V and fill factor of 88.6%, and guaranteeing an optimal power conversion efficiency of at least 32.4% under 1 sun AM0 illumination even without an anti-reflective coating.

Gap junction systems in the rat vestibular labyrinth: immunohistochemical and ultrastructural analysis.

PubMed

Kikuchi, T; Adams, J C; Paul, D L; Kimura, R S

1994-09-01

The distribution of gap junctions within the vestibular labyrinth was investigated using immunohistochemistry and transmission electron microscopy. Connexin26-like immunoreactivity was observed among supporting cells in each vestibular sensory epithelium. Reaction product was also present in the transitional epithelium of each vestibular endorgan and in the planum semilunatum of crista ampullaris. No connexin26-like immunoreactivity was observed among thin wall epithelial cells or among vestibular dark cells. In addition, fibrocytes within vestibular connective tissue were positively immunostained. Reaction product was also detected in the melanocyte area just beneath dark cells. Ultrastructural observations indicated that a gap junction network of vestibular supporting cells extends to the transitional epithelium and planum semilunatum and forms an isolated epithelial cell gap junction system in each vestibular endorgan. In contrast, no gap junctions were found among wall epithelial cells or among dark cells. Fibrocytes and melanocytes were coupled by gap junctions and belong to the connective tissue cell gap junction system, which is continuous throughout the vestibular system and the cochlea. The possible functional significance of these gap junction systems is discussed.

New high-efficiency silicon solar cells

NASA Technical Reports Server (NTRS)

Daud, T.; Crotty, G. T.

1985-01-01

A design for silicon solar cells was investigated as an approach to increasing the cell open-circuit voltage and efficiency for flat-plate terrestrial photovoltaic applications. This deviates from past designs, where either the entire front surface of the cell is covered by a planar junction or the surface is textured before junction formation, which results in an even greater (up to 70%) junction area. The heavily doped front region and the junction space charge region are potential areas of high recombination for generated and injected minority carriers. The design presented reduces junction area by spreading equidiameter dot junctions across the surface of the cell, spaced about a diffusion length or less from each other. Various dot diameters and spacings allowed variations in total junction area. A simplified analysis was done to obtain a first-order design optimization. Efficiencies of up to 19% can be obtained. Cell fabrication involved extra masking steps for selective junction diffusion, and made surface passivation a key element in obtaining good collection. It also involved photolithography, with line widths down to microns. A method is demonstrated for achieving potentially high open-circuit voltages and solar-cell efficiencies.

Electron optics with ballistic graphene junctions

NASA Astrophysics Data System (ADS)

Chen, Shaowen

Electrons transmitted across a ballistic semiconductor junction undergo refraction, analogous to light rays across an optical boundary. A pn junction theoretically provides the equivalent of a negative index medium, enabling novel electron optics such as negative refraction and perfect (Veselago) lensing. In graphene, the linear dispersion and zero-gap bandstructure admit highly transparent pn junctions by simple electrostatic gating, which cannot be achieved in conventional semiconductors. Robust demonstration of these effects, however, has not been forthcoming. Here we employ transverse magnetic focusing to probe propagation across an electrostatically defined graphene junction. We find perfect agreement with the predicted Snell's law for electrons, including observation of both positive and negative refraction. Resonant transmission across the pn junction provides a direct measurement of the angle dependent transmission coefficient, and we demonstrate good agreement with theory. Comparing experimental data with simulation reveals the crucial role played by the effective junction width, providing guidance for future device design. Efforts toward sharper pn junction and possibility of zero field Veselago lensing will also be discussed. This work is supported by the Semiconductor Research Corporations NRI Center for Institute for Nanoelectronics Discovery and Exploration (INDEX).

Building a Six-Junction Inverted Metamorphic Concentrator Solar Cell

DOE PAGES

Geisz, John F.; Steiner, Myles A.; Jain, Nikhil; ...

2017-12-20

We propose practical six-junction (6J) inverted metamorphic multijunction (IMM) concentrator solar cell designs with the potential to exceed 50% efficiency using moderately high quality junction materials. We demonstrate the top three junctions and their monolithic integration lattice matched to GaAs using 2.1-eV AlGaInP, 1.7-eV AlGaAs or GaInAsP, and 1.4-eV GaAs with external radiative efficiencies >0.1%. We demonstrate tunnel junctions with peak tunneling current >400 A/cm 2 that are transparent to <2.1-eV light. We compare the bottom three GaInAs(p) junctions with bandgaps of 1.2, 1.0, and 0.7 eV grown on InP and transparent metamorphic grades with low dislocation densities. The solutionmore » to an integration challenge resulting from Zn diffusion in the GaAs junction is illustrated in a five-junction IMM. Excellent 1-sun performance is demonstrated in a complete 6J IMM device with VOC = 5.15 V, and a promising pathway toward >50% efficiency at high concentrations is presented.« less

Valley dependent transport in graphene L junction

NASA Astrophysics Data System (ADS)

Chan, K. S.

2018-05-01

We studied the valley dependent transport in graphene L junctions connecting an armchair lead and a zigzag lead. The junction can be used in valleytronic devices and circuits. Electrons injected from the armchair lead into the junction is not valley polarized, but they can become valley polarized in the zigzag lead. There are Fermi energies, where the current in the zigzag lead is highly valley polarized and the junction is an efficient generator of valley polarized current. The features of the valley polarized current depend sensitively on the widths of the two leads, as well as the number of dimers in the armchair lead, because this number has a sensitive effect on the band structure of the armchair lead. When an external potential is applied to the junction, the energy range with high valley polarization is enlarged enhancing its function as a generator of highly valley polarized current. The scaling behavior found in other graphene devices is also found in L junctions, which means that the results presented here can be extended to junctions with larger dimensions after appropriate scaling of the energy.

Metallic Junction Thermoelectric Device Simulations

NASA Technical Reports Server (NTRS)

Duzik, Adam J.; Choi, Sang H.

2017-01-01

Thermoelectric junctions made of semiconductors have existed in radioisotope thermoelectric generators (RTG) for deep space missions, but are currently being adapted for terrestrial energy harvesting. Unfortunately, these devices are inefficient, operating at only 7% efficiency. This low efficiency has driven efforts to make high-figure-of-merit thermoelectric devices, which require a high electrical conductivity but a low thermal conductivity, a combination that is difficult to achieve. Lowered thermal conductivity has increased efficiency, but at the cost of power output. An alternative setup is to use metallic junctions rather than semiconductors as thermoelectric devices. Metals have orders of magnitude more electrons and electronic conductivities higher than semiconductors, but thermal conductivity is higher as well. To evaluate the viability of metallic junction thermoelectrics, a two dimensional heat transfer MATLAB simulation was constructed to calculate efficiency and power output. High Seebeck coefficient alloys, Chromel (90%Ni-10%Cr) and Constantan (55%Cu-45%Ni), produced efficiencies of around 20-30%. Parameters such as the number of layers of junctions, lateral junction density, and junction sizes for both series- and parallel-connected junctions were explored.

JAM-C regulates tight junctions and integrin-mediated cell adhesion and migration.

PubMed

Mandicourt, Guillaume; Iden, Sandra; Ebnet, Klaus; Aurrand-Lions, Michel; Imhof, Beat A

2007-01-19

Junctional Adhesion Molecules (JAMs) have been described as major components of tight junctions in endothelial and epithelial cells. Tight junctions are crucial for the establishment and maintenance of cell polarity. During tumor development, they are remodeled, enabling neoplastic cells to escape from constraints imposed by intercellular junctions and to adopt a migratory behavior. Using a carcinoma cell line we tested whether JAM-C could affect tight junctions and migratory properties of tumor cells. We show that transfection of JAM-C improves the tight junctional barrier in tumor cells devoid of JAM-C expression. This is dependent on serine 281 in the cytoplasmic tail of JAM-C because serine mutation into alanine abolishes the specific localization of JAM-C in tight junctions and establishment of cell polarity. More importantly, the same mutation stimulates integrin-mediated cell migration and adhesion via the modulation of beta1 and beta3 integrin activation. These results highlight an unexpected function for JAM-C in controlling epithelial cell conversion from a static, polarized state to a pro-migratory phenotype.

Building a Six-Junction Inverted Metamorphic Concentrator Solar Cell

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

Geisz, John F.; Steiner, Myles A.; Jain, Nikhil

We propose practical six-junction (6J) inverted metamorphic multijunction (IMM) concentrator solar cell designs with the potential to exceed 50% efficiency using moderately high quality junction materials. We demonstrate the top three junctions and their monolithic integration lattice matched to GaAs using 2.1-eV AlGaInP, 1.7-eV AlGaAs or GaInAsP, and 1.4-eV GaAs with external radiative efficiencies >0.1%. We demonstrate tunnel junctions with peak tunneling current >400 A/cm 2 that are transparent to <2.1-eV light. We compare the bottom three GaInAs(p) junctions with bandgaps of 1.2, 1.0, and 0.7 eV grown on InP and transparent metamorphic grades with low dislocation densities. The solutionmore » to an integration challenge resulting from Zn diffusion in the GaAs junction is illustrated in a five-junction IMM. Excellent 1-sun performance is demonstrated in a complete 6J IMM device with VOC = 5.15 V, and a promising pathway toward >50% efficiency at high concentrations is presented.« less

Innovative architecture design for high performance organic and hybrid multi-junction solar cells

NASA Astrophysics Data System (ADS)

Li, Ning; Spyropoulos, George D.; Brabec, Christoph J.

2017-08-01

The multi-junction concept is especially attractive for the photovoltaic (PV) research community owing to its potential to overcome the Schockley-Queisser limit of single-junction solar cells. Tremendous research interests are now focused on the development of high-performance absorbers and novel device architectures for emerging PV technologies, such as organic and perovskite PVs. It has been predicted that the multi-junction concept is able to boost the organic and perovskite PV technologies approaching the 20% and 30% benchmarks, respectively, showing a bright future of commercialization of the emerging PV technologies. In this contribution, we will demonstrate innovative architecture design for solution-processed, highly functional organic and hybrid multi-junction solar cells. A simple but elegant approach to fabricating organic and hybrid multi-junction solar cells will be introduced. By laminating single organic/hybrid solar cells together through an intermediate layer, the manufacturing cost and complexity of large-scale multi-junction solar cells can be significantly reduced. This smart approach to balancing the photocurrents as well as open circuit voltages in multi-junction solar cells will be demonstrated and discussed in detail.

49 CFR 236.382 - Switch obstruction test.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Switch obstruction test. 236.382 Section 236.382... and Tests § 236.382 Switch obstruction test. Switch obstruction test of lock rod of each power-operated switch and lock rod of each hand-operated switch equipped with switch-and-lock-movement shall be...

49 CFR 236.382 - Switch obstruction test.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false Switch obstruction test. 236.382 Section 236.382... and Tests § 236.382 Switch obstruction test. Switch obstruction test of lock rod of each power-operated switch and lock rod of each hand-operated switch equipped with switch-and-lock-movement shall be...

49 CFR 236.382 - Switch obstruction test.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 4 2012-10-01 2012-10-01 false Switch obstruction test. 236.382 Section 236.382... and Tests § 236.382 Switch obstruction test. Switch obstruction test of lock rod of each power-operated switch and lock rod of each hand-operated switch equipped with switch-and-lock-movement shall be...

49 CFR 236.382 - Switch obstruction test.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Switch obstruction test. 236.382 Section 236.382... and Tests § 236.382 Switch obstruction test. Switch obstruction test of lock rod of each power-operated switch and lock rod of each hand-operated switch equipped with switch-and-lock-movement shall be...

49 CFR 236.382 - Switch obstruction test.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 4 2013-10-01 2013-10-01 false Switch obstruction test. 236.382 Section 236.382... and Tests § 236.382 Switch obstruction test. Switch obstruction test of lock rod of each power-operated switch and lock rod of each hand-operated switch equipped with switch-and-lock-movement shall be...

33 CFR 67.30-5 - Obstruction lights.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Obstruction lights. 67.30-5... Obstruction lights. (a) The obstruction lights shall be white or red lights as prescribed in Subpart 67.05 of... nautical mile 90 percent of the nights of the year. The lights shall be displayed at such height, above...

33 CFR 67.20-5 - Obstruction lights.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Obstruction lights. 67.20-5... Obstruction lights. The obstruction lights shall be white lights as prescribed in Subpart 67.05 of this part. The lights shall be of sufficient candlepower as to be visible at a distance of at least five nautical...

33 CFR 67.20-5 - Obstruction lights.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Obstruction lights. 67.20-5... Obstruction lights. The obstruction lights shall be white lights as prescribed in Subpart 67.05 of this part. The lights shall be of sufficient candlepower as to be visible at a distance of at least five nautical...

33 CFR 67.20-5 - Obstruction lights.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Obstruction lights. 67.20-5... Obstruction lights. The obstruction lights shall be white lights as prescribed in Subpart 67.05 of this part. The lights shall be of sufficient candlepower as to be visible at a distance of at least five nautical...

33 CFR 67.25-5 - Obstruction lights.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Obstruction lights. 67.25-5... Obstruction lights. (a) The obstruction lights shall be white lights as prescribed in Subpart 67.05 of this... miles 90 percent of the nights of the year. The lights shall be displayed not less than 20 feet above...

33 CFR 67.20-5 - Obstruction lights.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Obstruction lights. 67.20-5... Obstruction lights. The obstruction lights shall be white lights as prescribed in Subpart 67.05 of this part. The lights shall be of sufficient candlepower as to be visible at a distance of at least five nautical...

33 CFR 67.30-5 - Obstruction lights.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Obstruction lights. 67.30-5... Obstruction lights. (a) The obstruction lights shall be white or red lights as prescribed in Subpart 67.05 of... nautical mile 90 percent of the nights of the year. The lights shall be displayed at such height, above...

33 CFR 67.30-5 - Obstruction lights.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Obstruction lights. 67.30-5... Obstruction lights. (a) The obstruction lights shall be white or red lights as prescribed in Subpart 67.05 of... nautical mile 90 percent of the nights of the year. The lights shall be displayed at such height, above...

33 CFR 67.25-5 - Obstruction lights.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Obstruction lights. 67.25-5... Obstruction lights. (a) The obstruction lights shall be white lights as prescribed in Subpart 67.05 of this... miles 90 percent of the nights of the year. The lights shall be displayed not less than 20 feet above...

33 CFR 67.30-5 - Obstruction lights.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Obstruction lights. 67.30-5... Obstruction lights. (a) The obstruction lights shall be white or red lights as prescribed in Subpart 67.05 of... nautical mile 90 percent of the nights of the year. The lights shall be displayed at such height, above...

33 CFR 67.30-5 - Obstruction lights.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Obstruction lights. 67.30-5... Obstruction lights. (a) The obstruction lights shall be white or red lights as prescribed in Subpart 67.05 of... nautical mile 90 percent of the nights of the year. The lights shall be displayed at such height, above...

33 CFR 67.25-5 - Obstruction lights.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Obstruction lights. 67.25-5... Obstruction lights. (a) The obstruction lights shall be white lights as prescribed in Subpart 67.05 of this... miles 90 percent of the nights of the year. The lights shall be displayed not less than 20 feet above...

33 CFR 67.20-5 - Obstruction lights.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Obstruction lights. 67.20-5... Obstruction lights. The obstruction lights shall be white lights as prescribed in Subpart 67.05 of this part. The lights shall be of sufficient candlepower as to be visible at a distance of at least five nautical...