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Sample records for portosystemic shunt pathogenesis

  1. TRANSJUGULAR INTRAHEPATIC PORTOSYSTEMIC SHUNT

    PubMed Central

    Patidar, Kavish R.; Sydnor, Malcolm; Sanyal, Arun J.

    2014-01-01

    Transjugular intrahepatic portosystemic shunt (TIPS) is an established procedure for the complications of portal hypertension. The largest body of evidence for its use has been supported for recurrent or refractory variceal bleeding and refractory ascites. Its use has also been advocated for acute variceal bleed, hepatic hydrothorax, and hepatorenal syndrome. With the replacement of bare metal stents with polytetrafluoroethylen (PTFE) covered stents, shunt patency has improved dramatically thus improving outcomes. Therefore, reassessment of its utility, management of its complications, and understanding of various TIPS techniques is important. PMID:25438287

  2. Congenital Portosystemic Shunt: Our Experience

    PubMed Central

    Timpanaro, Tiziana; Passanisi, Stefano; Sauna, Alessandra; Trombatore, Claudia; Pennisi, Monica; Petrillo, Giuseppe; Smilari, Pierluigi; Greco, Filippo

    2015-01-01

    Introduction. Congenital portosystemic venous malformations are rare abnormalities in which the portal blood drains into a systemic vein and which are characterized by extreme clinical variability. Case Presentations. The authors present two case reports of a congenital extrahepatic portosystemic shunt (Type II). In the first patient, apparently nonspecific symptoms, such as headache and fatigue, proved to be secondary to hypoglycemic episodes related to the presence of a portosystemic shunt, later confirmed on imaging. During portal vein angiography, endovascular embolization of the portocaval fistula achieved occlusion of the anomalous venous tract. In the second patient, affected by Down's syndrome, the diagnosis of a portosystemic malformation was made by routine ultrasonography, performed to rule out concurrent congenital anomalies. Because of the absence of symptoms, we chose to observe this patient. Conclusions. These two case reports demonstrate the clinical heterogeneity of this malformation and the need for a multidisciplinary approach. As part of a proper workup, clinical evaluation must always be followed by radiographic diagnosis. PMID:25709849

  3. Aneurysmal portosystemic venous shunt: a case report.

    PubMed

    Bodner, G; Glück, A; Springer, P; König, P; Perkmann, R

    1999-10-01

    A case of an aneurysmal portosystemic venous shunt detected by colour Doppler ultrasound (CDUS) is presented. A young female patient complained of postprandial fatigue and had paroxysmal tachycardia. A direct vascular communication between right portal vein and right hepatic vein was found at CDUS and confirmed by direct portal angiogram. Using detachable coils a complete occlusion of the intrahepatic shunt was obtained. Reports from the literature regarding portovenous aneurysms are reviewed.

  4. Portosystemic Shunt Surgery in Patients with Idiopathic Noncirrhotic Portal Hypertension.

    PubMed

    Karagul, Servet; Yagci, Mehmet Ali; Tardu, Ali; Ertugrul, Ismail; Kirmizi, Serdar; Sumer, Fatih; Isik, Burak; Kayaalp, Cuneyt; Yilmaz, Sezai

    2016-01-01

    BACKGROUND Idiopathic noncirrhotic portal hypertension (INCPH) is a rare disease characterized by increased portal venous pressure in the absence of cirrhosis and other causes of liver diseases. The aim of the present study was to present our results in using portosystemic shunt surgery in patients with INCPH. MATERIAL AND METHODS Patients who had been referred to our Liver Transplantation Institute for liver transplantation and who had undergone surgery from January 2010 to December 2015 were retrospectively analyzed. Patients with INCPH who had undergone portosystemic shunt procedure were included in the study. Age, sex, symptoms and findings, type of portosystemic shunt, and postoperative complications were assessed. RESULTS A total of 1307 patients underwent liver transplantation from January 2010 to December 2015. Eleven patients with INCPH who did not require liver transplantation were successfully operated on with a portosystemic shunt procedure. The mean follow-up was 30.1±19 months (range 7-69 months). There was no mortality in the perioperative period or during the follow-up. Two patients underwent surgery again due to intra-abdominal hemorrhage; one had bleeding from the surgical site except the portacaval anastomosis and the other had bleeding from the h-graft anastomosis. No patient developed encephalopathy and no patient presented with esophageal variceal bleeding after portosystemic shunt surgery. Shunt thrombosis occurred in 1 patient (9.9%). Only 1 patient developed ascites, which was controlled medically. CONCLUSIONS Portosystemic shunt surgery is a safe and effective procedure for the treatment of patients with INCPH. PMID:27194018

  5. Congenital extrahepatic portosystemic shunt complicated by the development of hepatocellular carcinoma.

    PubMed

    Sharma, Ruchi; Suddle, Abid; Quaglia, Alberto; Peddu, Praveen; Karani, John; Satyadas, Thomas; Heaton, Nigel

    2015-10-01

    Congenital extrahepatic portosystemic shunt, also known as Abernethy malformation, is a rare congenital malformation. It causes shunting of blood through a communication between the portal and systemic veins such as a patent ductus venous. We report 3 cases of Abernethy malformation complicated by the development of hepatocellular carcinoma. Additionally, we comprehensively reviewed all previously reported cases and highlighted common features that may help in early diagnosis and appropriate management. Patients with Abernethy malformation may have an increased propensity to develop hepatocellular carcinoma. All 5 previously reported cases, plus the three of our patients, have a type 1 (complete) shunt suggesting a role for absent portal blood flow in the pathogenesis of hepatocellular carcinoma. Congenital extrahepatic portosystemic shunt should be sought for in cases with raised serum ammonia, hepatic encephalopathy or hepatocellular carcinoma in the absence of cirrhosis. PMID:26459734

  6. Should transjugular intrahepatic portosystemic shunt stent grafts be underdilated?

    PubMed

    Gaba, Ron C; Parvinian, Ahmad; Minocha, Jeet; Casadaban, Leigh C; Knuttinen, M Grace; Ray, Charles E; Bui, James T

    2015-03-01

    Although underdilation of transjugular intrahepatic portosystemic shunt (TIPS) stent grafts is commonly performed to limit complications arising from excessive portosystemic shunting, it is uncertain whether underdilated stents retain their smaller diameter indefinitely or eventually expand to nominal caliber. In this investigation, postprocedure computed tomography (CT) was used to compare diameters of underdilated TIPSs and TIPSs expanded to a nominal diameter of 10 mm in 61 cases. The groups had comparable shunt diameters on post-TIPS imaging (9.8 mm vs 9.9 mm; P = .079), with similar incidences of hepatic encephalopathy (34% vs 20%; P = .372), indicating stent self-expansion over time, and bringing into question the advantages of underdilation for customization of shunt caliber.

  7. Congenital intrahepatic portosystemic shunts: Imaging findings and endovascular management

    PubMed Central

    Chandrasekharan, Rajsekar; Pullara, Sreekumar K; Thomas, Tixon; Kader, Nazar Puthukudiyil; Moorthy, Srikanth

    2016-01-01

    We present two cases of congenital intrahepatic portosystemic shunts in which the right portal vein directly communicated with the inferior venacava (IVC) in one patient and with the hepatic vein in the other. Multiple hepatic nodules consistent with focal nodular hyperplasia (FNH) were seen in the first patient. The second patient presented with recurrent history of hepatic encephalopathy. Percutaneous transhepatic embolization was performed using coils and Amplatz device following which she completely recovered. PMID:27081230

  8. Pulmonary Arterial Hypertension Associated with Congenital Portosystemic Shunts Treated with Transcatheter Embolization and Pulmonary Vasodilators.

    PubMed

    Sato, Haruka; Miura, Masanobu; Yaoita, Nobuhiro; Yamamoto, Saori; Tatebe, Shunsuke; Aoki, Tatsuo; Satoh, Kimio; Ota, Hideki; Takase, Kei; Sugimura, Koichiro; Shimokawa, Hiroaki

    2016-01-01

    Cardiopulmonary abnormalities are often present in patients with liver diseases. We herein report a case of congenital portosystemic shunts complicated by hepatopulmonary syndrome (HPS) and portopulmonary hypertension (PoPH). A 57-year-old woman complained of dyspnea and was subsequently diagnosed with HPS and PoPH caused by congenital portosystemic shunts. Although shunt closure by transcatheter embolization was successfully performed, her dyspnea worsened and pulmonary artery pressure and pulmonary vascular resistance elevated. Conventional vasodilator therapy was started, resulting in an improvement of pulmonary hypertension (PH). In some patients with congenital portosystemic shunts, shunt closure could exacerbate PH, and vasodilator therapy may be effective. PMID:27580545

  9. The Evolution of Transjugular Intrahepatic Portosystemic Shunt: Tips

    PubMed Central

    Fanelli, Fabrizio

    2014-01-01

    Since Richter's description in the literature in 1989 of the first procedure on human patients, transjugular intrahepatic portosystemic shunt (TIPS) has been worldwide considered as a noninvasive technique to manage portal hypertension complications. TIPS succeeds in lowering the hepatic sinusoidal pressure and in increasing the circulatory flow, thus reducing sodium retention, ascites recurrence, and variceal bleeding. Required several revisions of the shunt TIPS can be performed in case of different conditions such as hepatorenal syndrome, hepatichydrothorax, portal vein thrombosis, and Budd-Chiari syndrome. Most of the previous studies on TIPS procedure were based on the use of bare stents and most patients chose TIPS 2-3 years after traditional treatment, thus making TIPS appear to be not superior to endoscopy in survival rates. Bare stents were associated with higher incidence of shunt failure and consequently patients required several revisions during the follow-up. With the introduction of a dedicated e-PTFE covered stent-graft, these problems were completely solved, No more reinterventions are required with a tremendous improvement of patient's quality of life. One of the main drawbacks of the use of e-PTFE covered stent-graft is higher incidence of hepatic encephalopathy. In those cases refractory to the conventional medical therapy, a shunt reduction must be performed. PMID:27335841

  10. Assessment of surgical portosystemic shunts and associated complications: The diagnostic and therapeutic role of radiologists.

    PubMed

    Taslakian, Bedros; Faraj, Walid; Khalife, Mohammad; Al-Kutoubi, Aghiad; El-Merhi, Fadi; Saade, Charbel; Hallal, Ali; Haydar, Ali

    2015-08-01

    Surgical portosystemic shunting, the formation of a vascular connection between the portal and systemic venous circulation, has been used as a treatment to reduce portal venous pressure. Although the use of portosystemic shunt surgery in the management of portal hypertension has declined during the past decade in favour of alternative therapies, and subsequently surgeons and radiologists became less familiar with the procedure, it remains a well-established treatment. Knowledge of different types of surgical portosystemic shunts, their pathophysiology and complications will help radiologists improve communication with surgeons and enhance their understanding of the diagnostic and therapeutic role of radiology in the assessment and management of these shunts. Optimal assessment of the shunt is essential to determine its patency and allow timely intervention. Both non-invasive and invasive imaging modalities complement each other in the evaluation of surgical portosystemic shunts. Interventional radiology plays an important role in the management of complications, such as shunt thrombosis and stenosis. This article describes the various types of surgical portosystemic shunts, explains the anatomy and pathophysiology of these shunts, illustrates the pearls and pitfalls of different imaging modalities in the assessment of these shunts and demonstrates the role of radiologists in the interventional management of complications.

  11. Persistent portosystemic shunts after deceased donor liver transplant causing episodic hepatic encephalopathy despite good graft function

    PubMed Central

    Barritt, A. Sidney; Fried, Michael W.; Hayashi, Paul H.

    2011-01-01

    We describe two cases of post liver transplant encephalopathy caused by persistent portosystemic shunts despite good graft function. Such recurrence of encephalopathy due to persistent shunting has not been reported in the deceased donor liver transplant literature. Our patients had episodic hepatic encephalopathy concordant with elevated serum ammonia levels due to well documented persistent portosystemic shunts. In one of our cases, the shunt was obliterated via coil embolization. This patient's encephalopathy resolved completely and has not recurred over seven months of follow up. The second patient has declined an intervention, but has remained symptom free on maintenance lactulose and rifaximin. PMID:19655248

  12. Treatment of Portosystemic Shunt Myelopathy with a Stent Graft Deployed through a Transjugular Intrahepatic Route

    SciTech Connect

    Jain, Deepak Arora, Ankur; Deka, Pranjal; Mukund, Amar Bhatnagar, Shorav; Jindal, Deepti Kumar, Niteen Pamecha, Viniyendra

    2013-08-01

    A case of surgically created splenorenal shunt complicated with shunt myelopathy was successfully managed by placement of a stent graft within the splenic vein to close the portosystemic shunt and alleviate myelopathy. To our knowledge, this is the first report of a case of shunt myelopathy in a patient with noncirrhotic portal fibrosis without cirrhosis treated by a novel technique wherein a transjugular intrahepatic route was adopted to deploy the stent graft.

  13. Transjugular Intrahepatic Portosystemic Shunt (TIPS): Current Status and Future Possibilities

    SciTech Connect

    Bilbao, Jose Ignacio; Quiroga, Jorge; Herrero, Jose Ignacio; Benito, Alberto

    2002-08-15

    Since the insertion of the first TIPS in 1989 much has been learned about this therapeutic procedure. It has an established role for the treatment of some complications of portal hypertension: prevention of recurrent variceal bleeding and rescue of patients with acute uncontrollable variceal bleeding. In addition TIPS is useful for Budd-Chiari syndrome, refractory ascites and hepatorenal syndrome, although its specific role in these indications remains to be definitively established. However, the decrease in sinusoidal blood flow induced by TIPS can lead to the patient developing hepatic encephalopathy and liver failure in some cases. Therefore, TIPS should be used with caution in patients with very poor liver function. From a technical point of view, successful placement of TIPS is achieved in more than 98% of cases by experienced groups. At present, evaluation of TIPS dysfunction based on morphology probably leads to an overdiagnosis of this complication since most of these cases are not associated with clinical manifestations (recurrent bleeding or refractory ascites). The major disadvantage of TIPS remains its poor long-term patency requiring a mandatory surveillance program. The indicator for shunt function/malfunction should be the portosystemic pressure gradient, which is best assessed by intravascular measurements. Shunt obstructions may be prevented or reduced by the use of stent-grafts in the future.

  14. Transjugular Intrahepatic Portosystemic Shunts in Children with Biliary Atresia

    SciTech Connect

    Huppert, Peter E.; Goffette, Pierre; Sokal, Emil M.; Schweizer, Paul; Claussen, Claus D.

    2002-12-15

    Purpose: We retrospectively evaluated the technical and long-term clinical results of transjugularintrahepatic portosystemic shunts (TIPS) in children with portal hypertension and biliary atresia (BA). Methods: Nine children with BA and recurrent bleeding from esophagogastric and/or intestinal varices were treated by TIPS at the age of 34-156 months and followed-up in two centers. Different types of stents were used. Results: Shunt insertion succeeded in all patients, but in two a second procedure was necessary. Seven procedures lasted more than 3 hr, mainly due to difficult portal vein puncture.Variceal bleeding ceased in all patients; however, 16 reinterventions were performed in eight patients for clinical reasons (n =11) and sonographically suspected restenosis (n =5). Four patients underwent successful liver transplantation 4-51 months after TIPS and five are in good clinical conditions 64-75 months after TIPS. Conclusions: TIPS in children with BA is technically difficult, mainly due to periportal fibrosis and small portal veins. Frequency of reinterventions seems to be higher compared with adults.

  15. Transjugular Intrahepatic Portosystemic Shunt Dysfunction: Concordance of Clinical Findings, Doppler Ultrasound Examination, and Shunt Venography

    PubMed Central

    Owen, Joshua M; Gaba, Ron Charles

    2016-01-01

    Objectives: The objective of this study was to evaluate the concordance between clinical symptoms, Doppler ultrasound (US), and shunt venography for the detection of stent-graft transjugular intrahepatic portosystemic shunt (TIPS) dysfunction. Materials and Methods: Forty-one patients (M:F 30:11, median age 55 years) who underwent contemporaneous clinical exam, Doppler US, and TIPS venography between 2003 and 2014 were retrospectively studied. Clinical symptoms (recurrent ascites or variceal bleeding) were dichotomously classified as present/absent, and US and TIPS venograms were categorized in a binary fashion as normal/abnormal. US abnormalities included high/low (>190 or <90 cm/s) TIPS velocity, significant velocity rise/fall (>50 cm/s), absent flow, and return of antegrade intra-hepatic portal flow. Venographic abnormalities included shunt stenosis/occlusion and/or pressure gradient elevation. Clinical and imaging concordance rates were calculated. Results: Fifty-two corresponding US examinations and venograms were assessed. The median time between studies was 3 days. Forty of 52 (77%) patients were symptomatic, 33/52 (64%) US examinations were abnormal, and 20/52 (38%) TIPS venograms were abnormal. Concordance between clinical symptoms and TIPS venography was 48% (25/52), while the agreement between US and shunt venography was 65% (34/52). Clinical symptoms and the US concurred in 60% (31/52) of the patients. The sensitivity of clinical symptoms and US for the detection of venographically abnormal shunts was 80% (16/20) and 85% (17/20), respectively. Both clinical symptoms and the US had low specificity (25%, 8/32 and 50%, 16/32) for venographically abnormal shunts. Conclusion: Clinical findings and the US had low concordance rates with TIPS venography, with acceptable sensitivity but poor specificity. These findings suggest the need for improved noninvasive imaging methods for stent-graft TIPS surveillance. PMID:27563495

  16. Current diagnosis and management of post-transjugular intrahepatic portosystemic shunt refractory hepatic encephalopathy.

    PubMed

    Pereira, Keith; Carrion, Andres F; Martin, Paul; Vaheesan, Kirubahara; Salsamendi, Jason; Doshi, Mehul; Yrizarry, Jose M

    2015-12-01

    Transjugular intrahepatic portosystemic shunt has evolved into an important option for management of complications of portal hypertension. The use of polytetrafluoroethylene covered stents enhances shunt patency. Hepatic encephalopathy (HE) remains a significant problem after TIPS placement. The approach to management of patients with refractory hepatic encephalopathy typically requires collaboration between different specialties. Patient selection for TIPS requires careful evaluation of risk factors for HE. TIPS procedure-related technical factors like stent size, attention to portosystemic pressure gradient reduction and use of adjunctive variceal embolization maybe important. Conservative medical therapy in combination with endovascular therapies often results in resolution or substantial reduction of symptoms. Liver transplantation is, however, the ultimate treatment. PMID:26332169

  17. Vascular plug-assisted retrograde transvenous obliteration of portosystemic shunts for refractory hepatic encephalopathy: a case report.

    PubMed

    Park, Jonathan K; Cho, Sung-Ki; Kee, Stephen; Lee, Edward W

    2014-01-01

    While balloon-assisted retrograde transvenous obliteration (BRTO) has been used for two decades in Asia for the management of gastric variceal bleeding, it is still an emerging therapy elsewhere. Given the shunt closure brought about by the procedure, BRTO has also been used for the management of portosystemic encephalopathy with promising results. Modified versions of BRTO have been developed, including plug-assisted retrograde transvenous obliteration (PARTO), where a vascular plug is deployed within a portosystemic shunt. To our knowledge, we present the first North American case of PARTO in the setting of a large splenorenal shunt for the management of portosystemic encephalopathy.

  18. Hepatic encephalopathy due to intrahepatic portosystemic venous shunt successfully treated by balloon occluded retrograde transvenous embolization with GDCs.

    PubMed

    Yamagami, Takuji; Yoshimatsu, Rika; Miura, Hiroshi; Hasebe, Terumitsu; Koide, Kazuma

    2012-01-01

    We report a 65-year-old man with hepatic encephalopathy due to an intrahepatic portosystemic venous shunt that was successfully occluded by balloon occluded retrograde transvenous embolization with Guglielmi and interlocking detachable coils as performed percutaneously.

  19. Hepatic encephalopathy due to intrahepatic portosystemic venous shunt successfully treated by balloon occluded retrograde transvenous embolization with GDCs

    PubMed Central

    Yamagami, Takuji; Yoshimatsu, Rika; Miura, Hiroshi; Hasebe, Terumitsu; Koide, Kazuma

    2012-01-01

    We report a 65-year-old man with hepatic encephalopathy due to an intrahepatic portosystemic venous shunt that was successfully occluded by balloon occluded retrograde transvenous embolization with Guglielmi and interlocking detachable coils as performed percutaneously. PMID:23986827

  20. Evaluation of hepatic steatosis in dogs with congenital portosystemic shunts using Oil Red O staining.

    PubMed

    Hunt, G B; Luff, J A; Daniel, L; Van den Bergh, R

    2013-11-01

    The aims of this prospective study were to quantify steatosis in dogs with congenital portosystemic shunts (CPS) using a fat-specific stain, to compare the amount of steatosis in different lobes of the liver, and to evaluate intra- and interobserver variability in lipid point counting. Computer-assisted point counting of lipid droplets was undertaken following Oil Red O staining in 21 dogs with congenital portosystemic shunts and 9 control dogs. Dogs with congenital portosystemic shunts had significantly more small lipid droplets (<6 μ) than control dogs (P = .0013 and .0002, respectively). There was no significant difference in steatosis between liver lobes for either control dogs and CPS dogs. Significant differences were seen between observers for the number of large lipid droplets (>9 μ) and lipogranulomas per tissue point (P = .023 and .01, respectively). In conclusion, computer-assisted counting of lipid droplets following Oil Red O staining of liver biopsy samples allows objective measurement and detection of significant differences between dogs with CPS and normal dogs. This method will allow future evaluation of the relationship between different presentations of CPS (anatomy, age, breed) and lipidosis, as well as the impact of hepatic lipidosis on outcomes following surgical shunt attenuation.

  1. T1-201 per rectum: A noninvasive method for evaluating portosystemic shunt

    SciTech Connect

    Verdickt, X.; Reding, P.; Tshiamala, P.; Ham, H.R.

    1984-01-01

    Portosystemic shunt is one of the most important complications of liver cirrhosis. Unfortunately, current methods for detecting and quantifying this shunt are either non-specific or associated with significant morbidity. The aim of this work was to evaluate the clinical value of a new non-traumatic method which consisted of administrating T1-201 per rectum and monitoring the absorbed activity using a camera and a computer system. The method assumes that in the absence of portosystemic shunt, most of the absorbed activity will be fixed in the liver while in the presence of this shunt, some of the activity will be fixed in the myocardium. The ratio of heart to liver activity can therefore be used to evaluate the importance of the portosystemic shunt. 34 subjects have been studied. The ratio of heart to liver activity at the 25th minute after the tracer administration is higher in patients with liver cirrhosis (n=22, m=.9, s.d.=.37) than in patients with steatosis (n=10, m=.28, s.d.=.03). In two healthy subjects investigated the H/L ratio was .27 and .30. The reproducibility of the test was evaluated in 8 subjects and showed a good reproducibility (mean of difference =.03, range=.01 to .07). Patients with esophageal varices had always a high H/L ratio while some patients with liver cirrhosis without esophageal varices had also high H/L ratio, probably due to the presence of intrahepatic shunt. The authors' results showed the value of this new non-traumatic test for detecting and quantifying extra- as well as intrahepatic portosystematic shunt.

  2. Doppler ultrasound evaluation of transjugular intrahepatic portosystemic shunt function: pitfalls and artifacts.

    PubMed

    Wachsberg, Ronald H

    2003-09-01

    The current literature reflects controversy regarding the accuracy of Doppler ultrasound for the detection of transjugular intrahepatic portosystemic shunt (TIPS) malfunction. Experience has revealed many pitfalls and artifacts that can potentially interfere with the proper performance and interpretation of Doppler studies in patients with TIPS. In this article the author discusses and illustrates the spectrum of pitfalls that may be encountered during Doppler evaluation of TIPS function. PMID:14571161

  3. Asymptomatic Intrahepatic Portosystemic Venous Shunt: To Treat or Not To Treat?

    PubMed

    Palvanov, Arkadiy; Marder, Ruth Leah; Siegel, David

    2016-09-01

    Intrahepatic portosystemic venous shunts (IPSVSs) are rare vascular malformations. They can be asymptomatic or present with various symptoms including encephalopathy. We present two cases of IPSVS, one involving a patient presenting with altered mental status and the other discovered incidentally. While there is no question that patients presenting with symptomatic IPSVS should undergo definitive treatment, there is no consensus regarding elective therapy for asymptomatic lesions. PMID:27574389

  4. Asymptomatic Intrahepatic Portosystemic Venous Shunt: To Treat or Not To Treat?

    PubMed

    Palvanov, Arkadiy; Marder, Ruth Leah; Siegel, David

    2016-09-01

    Intrahepatic portosystemic venous shunts (IPSVSs) are rare vascular malformations. They can be asymptomatic or present with various symptoms including encephalopathy. We present two cases of IPSVS, one involving a patient presenting with altered mental status and the other discovered incidentally. While there is no question that patients presenting with symptomatic IPSVS should undergo definitive treatment, there is no consensus regarding elective therapy for asymptomatic lesions.

  5. Portosystemic shunting in portal hypertension: evaluation with portal scintigraphy with transrectally administered I-123 IMP

    SciTech Connect

    Kashiwagi, T.; Azuma, M.; Ikawa, T.; Takehara, T.; Matsuda, H.; Yoshioka, H.; Mitsutani, N.; Koizumi, T.; Kimura, K.

    1988-10-01

    Portosystemic shunting was evaluated with rectal administration of iodine-123 iodoamphetamine (IMP) in seven patients without liver disease and 53 patients with liver cirrhosis. IMP (2-3 mCi (74-111 MBq)) was administered to the rectum through a catheter. Images of the chest and abdomen were obtained for up to 60 minutes with a scintillation camera interfaced with a computer. In all patients, images of the liver and/or lungs were observed within 5-10 minutes and became clear with time. In patients without liver disease, only liver images could be obtained, whereas the lung was visualized with or without the liver in all patients with liver cirrhosis. The portosystemic shunt index was calculated by dividing counts of lungs by counts of liver and lung. These values were significantly higher in liver cirrhosis, especially in the decompensated stage. Transrectal portal scintigraphy with IMP appears to be a useful method for noninvasive and quantitative evaluation of portosystemic shunting in portal hypertension.

  6. Pancreaticoportal Fistula and Disseminated Fat Necrosis After Revision of a Transjugular Intrahepatic Portosystemic Shunt

    SciTech Connect

    Klein, Seth J. Saad, Nael; Korenblat, Kevin; Darcy, Michael D.

    2013-04-15

    A 59-year old man with alcohol related cirrhosis and portal hypertension was referred for transjugular intrahepatic portosystemic shunt (TIPS) to treat his refractory ascites. Ten years later, two sequential TIPS revisions were performed for shunt stenosis and recurrent ascites. After these revisions, he returned with increased serum pancreatic enzyme levels and disseminated superficial fat necrosis; an iatrogenic pancreaticoportal vein fistula caused by disruption of the pancreatic duct was suspected. The bare area of the TIPS was subsequently lined with a covered stent-graft, and serum enzyme levels returned to baseline. In the interval follow-up period, the patient has clinically improved.

  7. Transjugular intrahepatic portosystemic shunt combined with esophagogastric variceal embolization in the treatment of a large gastrorenal shunt

    PubMed Central

    Jiang, Qin; Wang, Ming-Quan; Zhang, Guo-Bing; Wu, Qiong; Xu, Jian-Ming; Kong, De-Run

    2016-01-01

    AIM: To evaluate the efficacy and safety of transjugular intrahepatic portosystemic shunt (TIPS) combined with stomach and esophageal variceal embolization (SEVE) in cirrhotic patients with a large gastrorenal vessel shunt (GRVS). METHODS: Eighty-one cirrhotic patients with gastric variceal bleeding (GVB) associated with a GRVS were enrolled in the study and accepted TIPS combined with SEVE (TIPS + SEVE), by which portosystemic pressure gradient (PPG), biochemical, TIPS-related complications, shunt dysfunction, rebleeding, and death were evaluated. RESULTS: The PPGs before TIPS were greater than 12 mmHg in 81 patients. TIPS + SEVE treatment caused a significant decrease in PPG (from 37.97 ± 6.36 mmHg to 28.15 ± 6.52 mmHg, t = 19.22, P < 0.001). The percentage of reduction in PPG was greater than 20% from baseline. There were no significant differences in albumin, alanine aminotransferase, aspartate aminotransferase, bilirubin, prothrombin time, or Child-Pugh score before and after operation. In all patients, rebleeding rates were 3%, 6%, 12%, 18%, and 18% at 1, 3, 6, 12, and 18 mo, respectively. Five patients (6.2%) were diagnosed as having hepatic encephalopathy. The rates of shunt dysfunction were 0%, 4%, 9%, 26%, and 26%, at 1, 3, 6, 12, and 18 mo, respectively. The cumulative survival rates in 1, 3, 6, 12, and 18 mo were 100%, 100%, 95%, 90%, and 90%, respectively. CONCLUSION: Our preliminary results indicated that the efficacy and safety of TIPS + SEVE were satisfactory in cirrhotic patients with GVB associated with a GRVS (GVB + GRVS). PMID:27458505

  8. Staged Transcatheter Treatment of Portal Hypoplasia and Congenital Portosystemic Shunts in Children

    SciTech Connect

    Bruckheimer, Elchanan Dagan, Tamir; Atar, Eli; Schwartz, Michael; Kachko, Ludmila; Superina, Riccardo; Amir, Gabriel; Shapiro, Rivka; Birk, Einat

    2013-12-15

    Purpose: Congenital portosystemic shunts (CPSS) with portal venous hypoplasia cause hyperammonemia. Acute shunt closure results in portal hypertension. A transcatheter method of staged shunt reduction to afford growth of portal vessels followed by shunt closure is reported. Methods: Pressure measurements and angiography in the CPSS or superior mesenteric artery (SMA) during temporary occlusion of the shunt were performed. If vessels were diminutive and the pressure was above 18 mmHg, a staged approach was performed, which included implantation of a tailored reducing stent to reduce shunt diameter by {approx}50 %. Recatheterization was performed approximately 3 months later. If the portal pressure was below 18 mmHg and vessels had developed, the shunt was closed with a device. Results: Six patients (5 boys, 1 girl) with a median age of 3.3 (range 0.5-13) years had CPSS portal venous hypoplasia and hyperammonemia. Five patients underwent staged closure. One patient tolerated acute closure. One patient required surgical shunt banding because a reducing stent could not be positioned. At median follow-up of 3.8 (range 2.2-8.4) years, a total of 21 procedures (20 transcatheter, 1 surgical) were performed. In all patients, the shunt was closed with a significant reduction in portal pressure (27.7 {+-} 11.3 to 10.8 {+-} 1.8 mmHg; p = 0.016), significant growth of the portal vessels (0.8 {+-} 0.5 to 4.0 {+-} 2.4 mm; p = 0.037), and normalization of ammonia levels (202.1 {+-} 53.6 to 65.7 {+-} 9.6 {mu}mol/L; p = 0.002) with no complications. Conclusion: Staged CPSS closure is effective in causing portal vessel growth and treating hyperammonemia.

  9. Hepatic Veins and Inferior Vena Cava Thrombosis in a Child Treated by Transjugular Intrahepatic Portosystemic Shunt

    SciTech Connect

    Carnevale, Francisco Cesar Santos, Aline Cristine Barbosa; Tannuri, Uenis; Cerri, Giovanni Guido

    2010-06-15

    We report the case of a 9-year-old boy with portal hypertension, due to Budd-Chiari syndrome, and retrohepatic inferior vena cava thrombosis, submitted to a transjugular intrahepatic portosystemic shunt (TIPS) by connecting the suprahepatic segment of the inferior vena cava directly to the portal vein. After 3 months, the withdrawal of anticoagulants promoted the thrombosis of the TIPS. At TIPS revision, thrombosis of the TIPS and the main portal vein and clots at the splenic and the superior mesenteric veins were found. Successful angiography treatment was performed by thrombolysis and balloon angioplasty of a severe stenosis at the distal edge of the stent.

  10. Transient Hemolytic Anemia after Transjugular Intrahepatic Portosystemic Stent Shunt

    PubMed Central

    Garcia-Rebollo, Sagrario; Santolaria-Fernández, Francisco; Diaz-Romero, Francisco; Rodriguez-Moreno, Fermin; Martinez-Riera, Antonio

    1996-01-01

    Management of variceal bleeding secondary to portal hypertension constitutes a challenging issue, particularly in child's C cirrhotic patients. Recently, transjugular placement of self-expanding metallic stents in the liver (TIPS), creating a shunt between the portal and hepatic branches has provided a safe and promising therapeutic approach in this clinical situation. We report here the case of a 66-year-old male cirrhotic patient who developed a moderately severe clinical picture of a Coombsnegative hemolytic anemia (serum hemoglobin, 93 g/l, serum bilirubin 160.74 umol/L (9.4 mg/dl), indirect 6.3 mg/dl (107.73 umol/L); serum LDH 1220 u/l, reticulocytes, 5.1%. serum ferritin, 1221 ug/1, schistocytes in peripheral blood smear) the week after undergoing a TIPS, suggesting the development ofa microangiopathic hemolytic anaemia secondary to red blood cell disruption by passing through the metallic network of the stent. PMID:8809588

  11. Transjugular Intrahepatic Portosystemic Shunt for the Treatment of Portal Hypertension in Noncirrhotic Patients with Portal Cavernoma

    PubMed Central

    Luo, Xuefeng; Zhou, Biao; Yao, Denghua; Ma, Huaiyuan; Jiang, Mingshan; Zhang, Hailong; Li, Xiao

    2014-01-01

    Background. The purpose of this study was to evaluate the safety and efficacy of transjugular intrahepatic portosystemic shunt (TIPS) placement in the management of portal hypertension in noncirrhotic patients with portal cavernoma. Methods. We conducted a single institution retrospective analysis of 15 noncirrhotic patients with portal cavernoma treated with TIPS placement. 15 patients (4 women and 11 men) were evaluated via the technical success of TIPS placement, procedural complications, and follow-up shunt patency. Results. TIPS placement was technically successful in 11 out of 15 patients (73.3%). Procedure-related complications were limited to a single instance of hepatic encephalopathy in one patient. In patients with successful shunt placement, the portal pressure gradient decreased from 25.8 ± 5.7 to 9.5 ± 4.2 mmHg (P < 0.001). TIPS dysfunction occurred in two patients during a median follow-up time of 45.2 months. Revision was not performed in one patient due to inadequate inflow. The other patient died of massive gastrointestinal bleeding in a local hospital. The remaining nine patients maintained functioning shunts through their last evaluation. Conclusions. TIPS is a safe and effective therapeutic treatment for noncirrhotic patients with symptomatic portal hypertension secondary to portal cavernoma. PMID:24868203

  12. Transjugular Intrahepatic Portosystemic Shunt Placement in Patients with Cirrhosis and Concomitant Portal Vein Thrombosis

    SciTech Connect

    Ha, Thuong G. Van Hodge, Justin; Funaki, Brian; Lorenz, Jonathan; Rosenblum, Jordan; Straus, Christopher; Leef, Jeff

    2006-10-15

    Purpose. To determine the safety and efficacy of transjugular intrahepatic portosystemic shunt (TIPS) creation in patients with liver cirrhosis complicated by thrombosed portal vein. Methods. This study reviewed 15 cases of TIPS creation in 15 cirrhotic patients with portal vein thrombosis at our institution over an 8-year period. There were 2 women and 13 men with a mean age of 53 years. Indications were refractory ascites, variceal hemorrhage, and refractory pleural effusion. Clinical follow-up was performed in all patients. Results. The technical success rate was 75% (3/4) in patients with chronic portal vein thrombosis associated with cavernomatous transformation and 91% (10/11) in patients with acute thrombosis or partial thrombosis, giving an overall success rate of 87%. Complications included postprocedural encephalopathy and localized hematoma at the access site. In patients with successful shunt placement, the total follow-up time was 223 months. The 30-day mortality rate was 13%. Two patients underwent liver transplantation at 35 days and 7 months, respectively, after TIPS insertion. One patient had an occluded shunt at 4 months with an unsuccessful revision. The remaining patients had functioning shunts at follow-up. Conclusion. TIPS creation in thrombosed portal vein is possible and might be a treatment option in certain patients.

  13. Abnormal Gas Diffusing Capacity and Portosystemic Shunt in Patients With Chronic Liver Disease

    PubMed Central

    Park, Moon-Seung; Lee, Min-Ho; Park, Yoo-Sin; Kim, Shin-Hee; Kwak, Min-Jung; Kang, Ju-Seop

    2012-01-01

    Background Pulmonary dysfunctions including the hepatopulmonary syndrome and portosystemic shunt are important complications of hepatic cirrhosis. To investigate the severity and nature of abnormal gas diffusing capacity and its correlation to portosystemic shunt in patients with chronic liver disease. Methods Forty-four patients with chronic liver disease (15 chronic active hepatitis (CAH), 16 Child-Pugh class A, and 13 Child-Pugh class B) without other diseases history were enrolled in the study. Evaluation of liver function tests, arterial blood gases analysis, ultrasonography, pulmonary function test including lung diffusing capacity of carbon monoxide (DLco), forced vital capacity(FVC), forced expiratory volume 1 seconds(FEV1), total lung capacity(TLC), DLco/AV(alveolar volume) and thallium-201 per rectum scintigraphy were performed. We were analyzed correlations between pulmonary function abnormalities and heart/liver (H/L) ratio in patients with chronic liver diseases. Results In CAH, percentage of patients with DLco and DLco/VA (< 80%) was 22.2 % but it was significantly increased to 47.2-54.5% in Child-Pugh class A and B patients. The means of DLco and DLco/VA were significantly (P < 0.05) decreased in Child-Pugh class. The mean H/L ratio in Child-Pugh class B increased markedly (P < 0.01) than those with CAH and Child-Pugh class A. The frequency of specific pulmonary function abnormality in patients with Child-Pugh class B was significantly (P < 0.01) greater than those with Child-Pugh class A and CAH. There was a inverse linear correlation between H/L ratio and DLco (r = -0.339, P < 0.05) and DLco/VA (r = -0.480, P < 0.01). Conclusion A total of 62% of patients with advanced liver disease have abnormal pulmonary diffusion capacity with a reduced DLco or DLco/VA and abnormal portosystemic shunt (increased H/L ratio) is common hemodynamic abnormality. Therefore, inverse linear correlation between DLco or DLco/VA and H/L ratio may be an important factor in

  14. Hepatic Encephalopathy Secondary to Intrahepatic Portosystemic Venous Shunt: Balloon-Occluded Retrograde Transvenous Embolization with n-Butyl Cyanoacrylate and Microcoils

    SciTech Connect

    Yamagami, Takuji; Nakamura, Toshiyuki; Iida, Shigeharu; Kato, Takeharu; Tanaka, Osamu; Matsushima, Shigenori; Ito, Hirotoshi; Okuyama, Chio; Ushijima, Yo; Shiga, Kensuke; Nishimura, Tsunehiko

    2002-06-15

    We report a 70-year-old woman with hepatic encephalopathy due to an intrahepatic portosystemic venous shunt that was successfully occluded by percutaneous transcatheter embolization with n-butyl cyanoacrylate and microcoils.

  15. Severe liver fibrosis caused by Schistosoma mansoni: management and treatment with a transjugular intrahepatic portosystemic shunt.

    PubMed

    Richter, Joachim; Bode, Johannes G; Blondin, Dirk; Kircheis, Gerald; Kubitz, Ralf; Holtfreter, Martha C; Müller-Stöver, Irmela; Breuer, Matthias; Hüttig, Falk; Antoch, Gerald; Häussinger, Dieter

    2015-06-01

    Liver diseases are common in inhabitants and migrants of tropical countries, where the liver can be exposed not only to toxins but also to many viral, bacterial, fungal, and parasitic infections. Schistosomiasis--a common parasitic infection that affects at least 240 million people worldwide, mostly in Africa--is regarded as the most frequent cause of liver fibrosis worldwide. We present a case of a 19-year-old male refugee from Guinea with recurrent oesophageal variceal bleeding due to schistosomal liver fibrosis refractory to endoscopic therapy. This case was an indication for portosystemic surgery, which is a highly invasive non-reversible intervention. An alternative, less invasive, reversible radiological procedure, used in liver cirrhosis, is the placement of a transjugular intrahepatic portosystemic shunt (TIPS). After thorough considerations of all therapeutic options we placed a TIPS in our patient. In more than 3 years of observation, he is clinically well apart from one episode of hepatic encephalopathy related to an acute episode of viral gastroenteritis. Bleeding from oesophageal varices has not recurred. In this Grand Round, we review the diagnostic approaches and treatment options for portal hypertension due to schistosomal liver fibrosis.

  16. Hyperammonemia and Systemic Inflammatory Response Syndrome Predicts Presence of Hepatic Encephalopathy in Dogs with Congenital Portosystemic Shunts

    PubMed Central

    Tivers, Mickey S.; Handel, Ian; Gow, Adam G.; Lipscomb, Vicky J.; Jalan, Rajiv; Mellanby, Richard J.

    2014-01-01

    Hepatic encephalopathy (HE) is an important cause of morbidity and mortality in patients with liver disease. The pathogenesis of he is incompletely understood although ammonia and inflammatory cytokines have been implicated as key mediators. To facilitate further mechanistic understanding of the pathogenesis of HE, a large number of animal models have been developed which often involve the surgical creation of an anastomosis between the hepatic portal vein and the caudal vena cava. One of the most common congenital abnormalities in dogs is a congenital portosystemic shunt (cpss), which closely mimics these surgical experimental models of HE. Dogs with a cPSS often have clinical signs which mimic clinical signs observed in humans with HE. Our hypothesis is that the pathogenesis of HE in dogs with a cPSS is similar to humans with HE. The aim of the study was to measure a range of clinical, haematological and biochemical parameters, which have been linked to the development of HE in humans, in dogs with a cPSS and a known HE grade. One hundred and twenty dogs with a cPSS were included in the study and multiple regression analysis of clinical, haematological and biochemical variables revealed that plasma ammonia concentrations and systemic inflammatory response syndrome scores predicted the presence of HE. Our findings further support the notion that the pathogenesis of canine and human HE share many similarities and indicate that dogs with cPSS may be an informative spontaneous model of human HE. Further investigations on dogs with cPSS may allow studies on HE to be undertaken without creating surgical models of HE thereby allowing the number of large animals used in animal experimentation to be reduced. PMID:24392080

  17. A Glasgow Tipple—transjugular intrahepatic portosystemic shunt insertion prior to Whipple resection

    PubMed Central

    Jabbar, Salman A.A.; Jamieson, Nigel B.; Morris, Andrew J.; Oien, Karin A.; Duthie, Fraser; McKay, Colin J.; Carter, Christopher R.; Dickson, Euan J.

    2016-01-01

    Abdominal surgery performed in patients with significant liver disease and portal hypertension is associated with high mortality rates, with even poorer outcomes associated with complex pancreaticobiliary operations. We report on a patient requiring portal decompression via transjugular intrahepatic portosystemic shunt (TIPS) prior to a pancreaticoduodenectomy. The 49-year-old patient presented with pain, jaundice and weight loss. At ERCP an edematous ampulla was biopsied, revealing high-grade dysplasia within a distal bile duct adenoma. Liver biopsy was performed to investigate portal hypertension, confirming congenital hepatic fibrosis (CHF). A TIPS was performed to enable a pancreaticoduodenectomy. Prophylactic TIPS can be performed for preoperative portal decompression for patients requiring pancreatic resection. A potentially curative resection was performed when abdominal surgery was initially thought impossible. Notably, CHF has been associated with the development of cholangiocarcinoma in only four previous instances, with this case being only the second reported distal bile duct cholangiocarcinoma. PMID:27177892

  18. Macroscopic hematuria caused by congenital portosystemic shunt and concomitant nutcracker syndrome.

    PubMed

    Lee, Sang Hyub; Lee, Dong-Gi

    2015-06-01

    Nutcracker syndrome (NCS) is an uncommon vascular abnormality that causes a variety of symptoms that range from asymptomatic microscopic hematuria to severe pelvic congestion. Congenital portosystemic shunt (CPSS) is an extremely rare anomaly that causes serious complications. Many cases of NCS and CPSS that have presented separately have been reported, but no cases of concomitant NCS and CPSS have been reported. We present a case of intermittent macroscopic hematuria in a patient with both NCS and CPSS. We diagnosed NCS on pressure gradient between the left renal vein (LRV) and the inferior vena cava. The presence of CPSS, which emerged from the LRV and connected to the extrahepatic portal vein, was confirmed on computed tomography. The interaction between NCS and CPSS resulted in mild intermittent macroscopic hematuria only, rather than the more common symptoms that occur when NCS or CPSS present separately. PMID:26113323

  19. Transjugular Intrahepatic Portosystemic Shunt in a Patient with Cavernomatous Portal Vein Occlusion

    SciTech Connect

    Kawamata, Hiroshi; Kumazaki, Tatsuo; Kanazawa, Hidenori; Takahashi, Shuji; Tajima, Hiroyuki; Hayashi, Hiromitsu

    2000-03-15

    A 23-year-old woman with liver cirrhosis secondary to primary sclerosing cholangitis was referred to us for the treatment of recurrent bleeding from esophageal varices that had been refractory to endoscopic sclerotherapy. Her portal vein was occluded, associated with cavernous transformation. A transjugular intrahepatic portosystemic shunt (TIPS) was performed after a preprocedural three-dimensional computed tomographic angiography evaluation to determine feasibility. The portal vein system was recanalized and portal blood flow increased markedly after TIPS. Esophageal varices disappeared 3 weeks after TIPS. Re-bleeding and hepatic encephalopathy were absent for 3 years after the procedure. We conclude that with adequate preprocedural evaluation, TIPS can be performed safely even in patients with portal vein occlusion associated with cavernous transformation.

  20. Could there be light at the end of the tunnel? Mesocaval shunting for refractory esophageal varices in patients with contraindications to transjugular intrahepatic portosystemic shunt

    PubMed Central

    Davis, Jessica; Chun, Albert K; Borum, Marie L

    2016-01-01

    Cirrhotic patients with recurrent variceal bleeds who have failed prior medical and endoscopic therapies and are not transjugular intrahepatic portosystemic shunt candidates face a grim prognosis with limited options. We propose that mesocaval shunting be offered to this group of patients as it has the potential to decrease portal pressures and thus decrease the risk of recurrent variceal bleeding. Mesocaval shunts are stent grafts placed by interventional radiologists between the mesenteric system, most often the superior mesenteric vein, and the inferior vena cava. This allows flow to bypass the congested hepatic system, reducing portal pressures. This technique avoids the general anesthesia and morbidity associated with surgical shunt placement and has been successful in several case reports. In this paper we review the technique, candidate selection, potential pitfalls and benefits of mesocaval shunt placement. PMID:27429715

  1. Could there be light at the end of the tunnel? Mesocaval shunting for refractory esophageal varices in patients with contraindications to transjugular intrahepatic portosystemic shunt.

    PubMed

    Davis, Jessica; Chun, Albert K; Borum, Marie L

    2016-07-01

    Cirrhotic patients with recurrent variceal bleeds who have failed prior medical and endoscopic therapies and are not transjugular intrahepatic portosystemic shunt candidates face a grim prognosis with limited options. We propose that mesocaval shunting be offered to this group of patients as it has the potential to decrease portal pressures and thus decrease the risk of recurrent variceal bleeding. Mesocaval shunts are stent grafts placed by interventional radiologists between the mesenteric system, most often the superior mesenteric vein, and the inferior vena cava. This allows flow to bypass the congested hepatic system, reducing portal pressures. This technique avoids the general anesthesia and morbidity associated with surgical shunt placement and has been successful in several case reports. In this paper we review the technique, candidate selection, potential pitfalls and benefits of mesocaval shunt placement. PMID:27429715

  2. Usefulness of Transjugular Intrahepatic Portosystemic Shunt in the Management of Bleeding Ectopic Varices in Cirrhotic Patients

    SciTech Connect

    Vidal, V.; Joly, L.; Perreault, P.; Bouchard, L.; Lafortune, M.; Pomier-Layrargues, G.

    2006-04-15

    Purpose. To evaluate the safety and efficacy of transjugular intrahepatic portosystemic shunt (TIPS) in the control of bleeding from ectopic varices. Methods. From 1995 to 2004, 24 cirrhotic patients, bleeding from ectopic varices, mean age 54.5 years (range 15-76 years), were treated by TIPS. The etiology of cirrhosis was alcoholic in 13 patients and nonalcoholic in 11 patients. The location of the varices was duodenal (n = 5), stomal (n = 8), ileocolic (n = 6), anorectal (n = 3), umbilical (n = 1), and peritoneal (n 1). Results. TIPS controlled the bleeding in all patients and induced a decrease in the portacaval gradient from 19.7 {+-} 5.4 to 6.4 {+-} 3.1 mmHg. Postoperative complications included self-limited intra-abdominal bleeding (n = 2), self-limited hemobilia (n = 1), acute thrombosis of the shunt (n = 1), and bile leak treated by a covered stent (n = 1). Median follow-up was 592 days (range 28-2482 days). Rebleeding occurred in 6 patients. In 2 cases rebleeding was observed despite a post-TIPS portacaval gradient lower than 12 mmHg and was controlled by variceal embolization; 1 patient underwent surgical portacaval shunt and never rebled; in 3 patients rebleeding was related to TIPS stenosis and treated with shunt dilatation with addition of a new stent. The cumulative rate of rebleeding was 23% and 31% at 1 and 2 years, respectively. One- and 2-year survival rates were 80% and 76%, respectively. Conclusion. The present series demonstrates that bleeding from ectopic varices, a challenging clinical problem, can be managed safely by TIPS placement with low rebleeding and good survival rates.

  3. Intravascular Ultrasound Guidance for Transjugular Intrahepatic Portosystemic Shunt Procedure in a Swine Model

    SciTech Connect

    Kew, Jacqueline; Davies, Roger P.

    2004-01-15

    A new method is described for guiding hepato-portalvenous puncture using a longitudinal side-view intravascular ultrasound(L-IVUS) transducer to assist in the performance of transjugularintrahepatic portosystemic shunt (TIPS) in three Australian swine.Simultaneous L-IVUS with an AcuNav (registered) 5-10 MHz 10 Fr transducer(Acuson Corporation, Mountain View, CA, USA) and fluoroscopy guidance was used to image and monitor the hepatic to portal venous puncture,dilatation of the tract, and deployment of the TIPS stent. Flow through the shunt could be demonstrated with both L-IVUS and angiography. TIPS was successful in all swine. The time for portal vein puncture once the target portal vein was identified was reduced at each attempt. The number of portal vein puncture attempts was 2, 1, and 1. No post-procedural complication was evident. L-IVUS-guided TIPS is practical and has the potential to improve safety by permitting simultaneous ultrasound and fluoroscopic imaging of the needle and target vascular structures. This technique allows for a more streamlined approach to TIPS, decreasing the fluoroscopic time (hence,decreasing the radiation exposure to the staff and patient) and anesthetic time. In addition, there are improved safety benefits obviating the need for wedged portography, facilitating avoidance of bile duct and hepatic arterial puncture, and minimizing hepatic injury by decreasing liver capsular puncture and the attendant risks.

  4. Embolization of Portosystemic Shunts for Treatment of Medically Refractory Hepatic Encephalopathy

    PubMed Central

    Lynn, Amanda M.; Singh, Siddharth; Congly, Stephen E.; Khemani, Disha; Johnson, David H.; Wiesner, Russell H.; Kamath, Patrick S.; Andrews, James C.; Leise, Michael D.

    2016-01-01

    Treatment options for refractory hepatic encephalopathy (HE) are limited. Patients who fail medical management may harbor large portosystemic shunts (PSSs) which are possible therapeutic targets. This study aims to describe patient selection, effectiveness, and safety of percutaneous PSS embolization in those with medically refractory HE. A retrospective evaluation of consecutive adult patients with medically refractory HE referred for PSS embolization at a tertiary center was performed (2003–2015). Patient data collected included the type of HE, medications, Model for End-Stage Liver Disease (MELD) score, shunt type, embolization approach, and materials used. Outcomes of interest were immediate (7 days), intermediate (1–4 months), and longer-term (6–12 months) effectiveness and periprocedural safety. Effectiveness was determined based on changes in hospitalization frequency, HE medications, and symptoms. Twenty-five patients with large PSS were evaluated for shunt embolization. Five were excluded due to high MELD scores (n = 1), comorbid conditions (n = 1), or technical considerations (n = 3). Of 20 patients who underwent embolization, 13 had persistent and 7 had recurrent HE; 100% (20/20) achieved immediate improvement. Durable benefit was achieved in 100% (18/18) and 92% (11/12) at 1–4 and 6–12 months, respectively. The majority (67%; 8/12) were free from HE-related hospitalizations over 1 year; 10% developed procedural complications, and all resolved. Six developed new or worsening ascites. In conclusion, PSS embolization is a safe and effective treatment strategy that should be considered for select patients with medically refractory HE. PMID:26970243

  5. ePTFE-Covered Stent-Grafts for Revision of Obstructed Transjugular Intrahepatic Portosystemic Shunt

    SciTech Connect

    Cejna, Manfred; Peck-Radosavljevic, Markus; Thurnher, Siegfried; Schoder, Maria; Rand, Thomas; Angermayr, Bernhard; Lammer, Johannes

    2002-10-15

    Purpose: To determine whether transjugular intrahepatic portosystemic shunt (TIPS) revisions with the Hemobahn stent-graft or the Viatorr endoprosthesis increase secondary patency rates. Methods: Between 1998 and June 1999,Hemobahn endoprostheses (W.L. Gore, Flagstaff, AZ, USA) were used for the revision of obstructed TIPS in seven patients, 51-67 years of age(mean 59 years). From June 1999 to 2000, the Viatorr endoprosthesis(W.L. Gore, Flagstaff, AZ, USA) was used for revision of obstructed TIPS in nine patients, 33-64 years of age (mean 49 years). Follow-up included duplex ultrasound, clinical assessment and venousportography. Results: The technical success rate of TIPS revision with the Hemobahn stent-graft was 100%. The pressure gradient decreased from a mean of 20 mmHg to 10 mmHg. The mean follow-up was 407 days (range 81-868 days). In two patients TIPS occlusion occurred at 62 and 529 days after stent-graft placement, respectively; in another two patients outflow tract stenosis occurred at 275 and 393 days,respectively. The technical success rate of TIPS revision with the Viatorr endoprosthesis was also 100%. The pressure gradient decreased from a mean of 27 mmHg to 11 mmHg. At a mean follow-up of 201 days(range 9-426 days), all Viatorr endoprostheses are still patent without in-graft stenosis, but angioplasty was required in two patients to treat a portosystemic pressure gradient > 15 mmHg. Four of the nine patients in the Viatorr group suffered from new encephalopathy after TIPS revision. Conclusion: The Viatorrendoprosthesis yielded optimal results with 100% in-graft patency rates at follow-up but had a high incidence of new encephalopathy,whereas the use of Hemobahn stent-graft for TIPS revision did not appear to improve the secondary patency rates in our series.

  6. Long-term results of complete and partial ligation of congenital portosystemic shunts in dogs.

    PubMed

    Hottinger, H A; Walshaw, R; Hauptman, J G

    1995-01-01

    The medical records of 65 dogs that underwent complete or partial ligation of a single congenital portosystemic shunt (CPSS) were reviewed to determine the long-term clinical clinical results. Information retrieved from the records included age at surgery, preligation (baseline) portal pressure, postligation portal pressure, change in portal pressure from baseline, complete or partial occlusion of the shunting vessel and fasting, and 2-hour postprandial bile acids from the preoperative, early postoperative (PO), and greater than 1 year PO time periods. A clinical rating score derived from a follow-up examination greater than 1 year PO was assigned to each dog. Of the 56 dogs that survived the perioperative period, 29 (52%) had complete and 27 (48%) had partial ligations. Age at surgery, pre- and postligation portal pressure, change in portal pressure from baseline and serum bile acid concentrations were not related to long-term clinical outcome. Clinical rating scores were significantly greater for dogs with partial CPSS ligations compared with dogs with complete ligations, indicating a less favorable clinical outcome for partial ligations. Fasting and 2-hour postprandial bile acid values at both PO time intervals were significantly greater in partial versus complete ligation groups. Follow-up information for more than 1 year was available on 18 of 29 dogs (62%) with complete ligations. All were clinically normal. Of 27 dogs with partial ligations, 11 dogs (41%) developed recurrence of clinical signs resulting in presentation to the university or referring veterinarian for additional surgery, medical management, or euthanasia. Only three dogs with partial CPSS ligation (11%) were clinically normal.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7571385

  7. Transjugular Intrahepatic Portosystemic Shunt Placement During Pregnancy: A Case Series of Five Patients

    SciTech Connect

    Ingraham, Christopher R. Padia, Siddharth A. Johnson, Guy E.; Easterling, Thomas R.; Liou, Iris W.; Kanal, Kalpana M.; Valji, Karim

    2015-10-15

    Background and AimsComplications of portal hypertension, such as variceal hemorrhage and ascites, are associated with significant increases in both mortality and complications during pregnancy. Transjugular intrahepatic portosystemic shunt (TIPS) is a well-established procedure for treating portal hypertension, but the safety of TIPS during pregnancy is largely unknown. In this series, we review five patients who underwent TIPS placement while pregnant and describe their clinical outcomes.MethodsFive pregnant patients with cirrhosis and portal hypertension underwent elective TIPS for complications of portal hypertension (four for secondary prevention of variceal bleeding and one for refractory ascites). Outcomes measured were recurrent bleeding episodes or need for further paracenteses during pregnancy, estimated radiation dose to the fetus and gestational age at delivery. All patients were followed after delivery to evaluate technical and clinical success of the procedure.ResultsAll five patients survived pregnancy and went on to deliver successfully. When TIPS was performed for secondary prevention of variceal bleeding (n = 4), no patients demonstrated variceal bleeding after TIPS placement. When TIPS was performed for refractory ascites (n = 1), no further paracenteses were required. All patients delivered successfully, albeit prematurely. Average radiation dose estimated to the fetus was 16.3 mGy.ConclusionsThis series suggests that TIPS can be performed in selective pregnant patients with portal hypertension, with little added risk to the mother or fetus.

  8. Transjugular Intrahepatic Portosystemic Shunt: Histologic and Immunohistochemical Study of Autopsy Cases

    SciTech Connect

    Terayama, Noboru; Matsui, Osamu; Kadoya, Masumi; Yoshikawa, Jun; Gabata, Toshifumi; Miyayama, Shiro; Takashima, Tsutomu; Kobayashi, Kenichi; Nakanishi, Isao; Nakanuma, Yasuni

    1997-11-15

    Purpose: To assess the histologic findings associated with stenosed and occluded transjugular intrahepatic portosystemic shunt (TIPS) tracts. Methods: Four TIPS tracts within three autopsy livers were histologically studied for vascular components by routine staining and immunohistochemical staining. TIPS had been performed for bleeding from esophageal varices in patients with cirrhosis of the liver. Results: Two TIPS, examined on days 4 and 53, showed occlusion by fibrin thrombus. In the former, no endothelial cells were detected, but coagulative necrosis of hepatocytes was found in the surrounding liver. In the latter, bile pigments were seen on the luminal surface. In the two other TIPS without tract occlusion, examined on days 49 and 293, a layer of endothelial cells, proliferation of smooth muscle cells, and deposition of an extracellular matrix such as collagen were confirmed. In the tract examined on day 293, there was protrusion of hepatocytes into the lumen through the stent wires. Conclusion: Short- and midterm TIPS occlusions were caused by thrombus forming after necrosis of hepatocytes and bile leakage, respectively. Long-term TIPS stenosis was associated with a combination of pseudointimal hyperplasia and ingrowth of hepatocytes.

  9. Combination therapy using PSE and TIO ameliorates hepatic encephalopathy due to intrahepatic portosystemic venous shunt in idiopathic portal hypertension

    PubMed Central

    Kojima, Seiichiro; Ito, Hiroyuki; Takashimizu, Shinji; Ichikawa, Hitoshi; Matsumoto, Tomohiro; Hasebe, Terumitsu

    2016-01-01

    A 64-year-old woman treated for anemia and ascites exhibited hepatic encephalopathy. Abdominal ultrasonography and computed tomography (CT) showed communication between the portal vein and the middle hepatic vein, indicating an intrahepatic portosystemic venous shunt (PSS). Since hepatic encephalopathy of the patient was resistant to medical treatment, interventional radiology was performed for the treatment of shunt obliteration. Hepatic venography showed anastomosis between the hepatic vein branches, supporting the diagnosis of idiopathic portal hypertension (IPH). To minimize the increase in portal vein pressure after shunt obliteration, partial splenic artery embolization (PSE) was first performed to reduce portal vein blood flow. Transileocolic venous obliteration (TIO) was then performed, and intrahepatic PSS was successfully obliterated using coils with n-butyl-2-cyanoacrylate (NBCA). In the present case, hepatic encephalopathy due to intrahepatic PSS in the patient with IPH was successfully treated by combination therapy using PSE and TIO.

  10. Combination therapy using PSE and TIO ameliorates hepatic encephalopathy due to intrahepatic portosystemic venous shunt in idiopathic portal hypertension.

    PubMed

    Kojima, Seiichiro; Ito, Hiroyuki; Takashimizu, Shinji; Ichikawa, Hitoshi; Matsumoto, Tomohiro; Hasebe, Terumitsu; Watanabe, Norihito

    2016-09-01

    A 64-year-old woman treated for anemia and ascites exhibited hepatic encephalopathy. Abdominal ultrasonography and computed tomography (CT) showed communication between the portal vein and the middle hepatic vein, indicating an intrahepatic portosystemic venous shunt (PSS). Since hepatic encephalopathy of the patient was resistant to medical treatment, interventional radiology was performed for the treatment of shunt obliteration. Hepatic venography showed anastomosis between the hepatic vein branches, supporting the diagnosis of idiopathic portal hypertension (IPH). To minimize the increase in portal vein pressure after shunt obliteration, partial splenic artery embolization (PSE) was first performed to reduce portal vein blood flow. Transileocolic venous obliteration (TIO) was then performed, and intrahepatic PSS was successfully obliterated using coils with n-butyl-2-cyanoacrylate (NBCA). In the present case, hepatic encephalopathy due to intrahepatic PSS in the patient with IPH was successfully treated by combination therapy using PSE and TIO. PMID:27651930

  11. Combination therapy using PSE and TIO ameliorates hepatic encephalopathy due to intrahepatic portosystemic venous shunt in idiopathic portal hypertension

    PubMed Central

    Kojima, Seiichiro; Ito, Hiroyuki; Takashimizu, Shinji; Ichikawa, Hitoshi; Matsumoto, Tomohiro; Hasebe, Terumitsu

    2016-01-01

    A 64-year-old woman treated for anemia and ascites exhibited hepatic encephalopathy. Abdominal ultrasonography and computed tomography (CT) showed communication between the portal vein and the middle hepatic vein, indicating an intrahepatic portosystemic venous shunt (PSS). Since hepatic encephalopathy of the patient was resistant to medical treatment, interventional radiology was performed for the treatment of shunt obliteration. Hepatic venography showed anastomosis between the hepatic vein branches, supporting the diagnosis of idiopathic portal hypertension (IPH). To minimize the increase in portal vein pressure after shunt obliteration, partial splenic artery embolization (PSE) was first performed to reduce portal vein blood flow. Transileocolic venous obliteration (TIO) was then performed, and intrahepatic PSS was successfully obliterated using coils with n-butyl-2-cyanoacrylate (NBCA). In the present case, hepatic encephalopathy due to intrahepatic PSS in the patient with IPH was successfully treated by combination therapy using PSE and TIO. PMID:27651930

  12. Simultaneous resection of liver cell adenomas and an intrahepatic portosystemic venous shunt with elevation of serum PIVKA-II level.

    PubMed

    Seyama, Yasuji; Sano, Keiji; Tang, Wei; Kokudo, Norihiro; Sakamoto, Yoshihiro; Imamura, Hiroshi; Makuuchi, Masatoshi

    2006-09-01

    A 27-year-old woman with no history of liver disease or oral contraceptive use presented with sudden abdominal pain. Laboratory data showed mild liver dysfunction with jaundice. Computed tomography and angiography revealed centrally located large liver cell adenomas (LCAs) and an intrahepatic portosystemic venous shunt (IHPSS) in the left lobe. The serum des-gamma-carboxy prothrombin (known as "protein induced by a lack of vitamin K or antagonist II," PIVKA-II) level was extremely high (6,647 mAU/ml), indicating malignant transformation of the tumors. Under the diagnosis of LCAs and IHPSS, the patient underwent simultaneous resection of the four liver tumors and portovenous shunt, and the hepatic vascular abnormality was resolved. The pathological diagnosis was LCAs without hepatocellular carcinoma. Immunohistochemical analysis with an anti-PIVKA-II monoclonal antibody showed positive staining of the adenoma cells. This case shows that LCA without malignant transformation can produce PIVKA-II, leading to high serum levels of PIVKA-II. Simultaneous resection of multiple tumors and closure of the portosystemic shunt are strongly recommended in a patient with LCA associated with IHPSS.

  13. Is color-Doppler US a reliable method in the follow-up of transjugular intrahepatic portosystemic shunt (TIPS)?

    PubMed Central

    Ricci, P.; Cantisani, V.; Lombardi, V.; Alfano, G.; D'Ambrosio, U.; Menichini, G.; Marotta, E.; Drudi, F.M.

    2007-01-01

    Transjugular intrahepatic portosystemic shunt (TIPS) has become a widely accepted treatment for complications of portal hypertension. Shunt or hepatic vein stenoses or occlusions are common short- and mid-term complications of the procedure, with a one-year primary patency ranging from 25% to 66%. When promptly identified, shunt stenosis or occlusion may be treated before the recurrence of gastrointestinal bleeding or ascites. The revision is usually successful and the primary-assisted patency of TIPS is approximately 85% at one year. Doppler sonography is a widely accepted screening modality for TIPS patients, both as a routine follow-up in asymptomatic patients and in those cases with clinically suspected TIPS malfunction. In a routine US follow-up, a TIPS patient is scheduled for a control 24 h after the procedure, and then after one week, 1 month, 3 months, and at 3-month intervals thereafter. Venography is at present performed solely on the basis of a suspected shunt dysfunction during the sonographic examination. Color-Doppler sonography is the most reliable method for monitoring the shunt function after TIPS implantation. Several studies have shown that Doppler sonography is a sensitive and relatively specific way to detect shunt malfunction, particularly when multiple parameters are examined. Achieving high sensitivity is optimal so that malfunctioning shunts can be identified and shunt revision can be performed before symptomatic deterioration. Venous angiography is at present indicated only on the basis of US suspicion of shunt compromise. Power-Doppler US and US contrast media can be useful in particular conditions, but are not really fundamental. PMID:23396711

  14. Three-Dimensional Path Planning Software-Assisted Transjugular Intrahepatic Portosystemic Shunt: A Technical Modification

    SciTech Connect

    Tsauo, Jiaywei Luo, Xuefeng; Ye, Linchao; Li, Xiao

    2015-06-15

    PurposeThis study was designed to report our results with a modified technique of three-dimensional (3D) path planning software assisted transjugular intrahepatic portosystemic shunt (TIPS).Methods3D path planning software was recently developed to facilitate TIPS creation by using two carbon dioxide portograms acquired at least 20° apart to generate a 3D path for overlay needle guidance. However, one shortcoming is that puncturing along the overlay would be technically impossible if the angle of the liver access set and the angle of the 3D path are not the same. To solve this problem, a prototype 3D path planning software was fitted with a utility to calculate the angle of the 3D path. Using this, we modified the angle of the liver access set accordingly during the procedure in ten patients.ResultsFailure for technical reasons occurred in three patients (unsuccessful wedged hepatic venography in two cases, software technical failure in one case). The procedure was successful in the remaining seven patients, and only one needle pass was required to obtain portal vein access in each case. The course of puncture was comparable to the 3D path in all patients. No procedure-related complication occurred following the procedures.ConclusionsAdjusting the angle of the liver access set to match the angle of the 3D path determined by the software appears to be a favorable modification to the technique of 3D path planning software assisted TIPS.

  15. Lipopolysaccharide and toll-like receptor 4 in dogs with congenital portosystemic shunts.

    PubMed

    Tivers, M S; Lipscomb, V J; Smith, K C; Wheeler-Jones, C P D; House, A K

    2015-12-01

    Surgical attenuation of a congenital portosystemic shunt (CPSS) results in increased portal vein perfusion, liver growth and clinical improvement. Portal lipopolysaccharide (LPS) is implicated in liver regeneration via toll-like receptor (TLR) 4 mediated cytokine activation. The aim of this study was to investigate factors associated with LPS in dogs with CPSS. Plasma LPS concentrations were measured in the peripheral and portal blood using a limulus amoebocyte lysate (LAL) assay. LPS concentration was significantly greater in the portal blood compared to peripheral blood in dogs with CPSS (P = 0.046) and control dogs (P = 0.002). LPS concentrations in the peripheral (P = 0.012) and portal (P = 0.005) blood of dogs with CPSS were significantly greater than those of control dogs. The relative mRNA expression of cytokines and TLRs was measured in liver biopsies from dogs with CPSS using quantitative PCR. TLR4 expression significantly increased following partial CPSS attenuation (P = 0.020). TLR4 expression was significantly greater in dogs that tolerated complete CPSS attenuation (P = 0.011) and those with good portal blood flow on pre-attenuation (P = 0.004) and post-attenuation (P = 0.015) portovenography. Serum interleukin (IL)-6 concentration was measured using a canine specific ELISA and significantly increased 24 h following CPSS attenuation (P < 0.001). Portal LPS was increased in dogs with CPSS, consistent with decreased hepatic clearance. TLR4 mRNA expression was significantly associated with portal blood flow and increased following surgery. These findings support the concept that portal LPS delivery is important in the hepatic response to surgical attenuation. Serum IL-6 significantly increased following surgery, consistent with LPS stimulation via TLR4, although this increase might be non-specific. PMID:26383860

  16. Radiofrequency Ablation for the Treatment of Hepatocellular Carcinoma in Patients with Transjugular Intrahepatic Portosystemic Shunts

    SciTech Connect

    Park, Jonathan K.; Al-Tariq, Quazi Z.; Zaw, Taryar M. Raman, Steven S. Lu, David S.K.

    2015-10-15

    PurposeTo assess radiofrequency (RF) ablation efficacy, as well as the patency of transjugular intrahepatic portosystemic shunts (TIPSs), in patients with hepatocellular carcinoma (HCC).Materials and MethodsRetrospective database review of patients with pre-existing TIPS undergoing RF ablation of HCC was conducted over a 159-month period ending in November 2013. TIPS patency pre- and post-RF ablation was assessed by ultrasound, angiography, and/or contrast-enhanced CT or MRI. Patient demographics and immediate post-RF ablation outcomes and complications were also reviewed.Results19 patients with 21 lesions undergoing 25 RF ablation sessions were included. Child-Pugh class A, B, and C scores were seen in 1, 13, and 5 patients, respectively. Eleven patients (58 %) ultimately underwent liver transplantation. Immediate technical success was seen in all ablation sessions without residual tumor enhancement (100 %). No patients (0 %) suffered liver failure within 1 month of ablation. Pre-ablation TIPS patency was demonstrated in 22/25 sessions (88 %). Of 22 cases with patent TIPS prior to ablation, post-ablation patency was demonstrated in 22/22 (100 %) at immediate post-ablation imaging and in 21/22 (95 %) at last follow-up (1 patient was incidentally noted to have occlusion 31 months later). No immediate complications were observed.ConclusionAblation efficacy was similar to the cited literature values for patients without TIPS. Furthermore, TIPS patency was preserved in the majority of cases. Patients with both portal hypertension and HCC are not uncommonly encountered, and a pre-existing TIPS does not appear to be a definite contraindication for RF ablation.

  17. Outcomes of Locoregional Tumor Therapy for Patients with Hepatocellular Carcinoma and Transjugular Intrahepatic Portosystemic Shunts

    SciTech Connect

    Padia, Siddharth A. Chewning, Rush H. Kogut, Matthew J. Ingraham, Christopher R. Johnson, Guy E.; Bhattacharya, Renuka; Kwan, Sharon W. Monsky, Wayne L. Vaidya, Sandeep; Hippe, Daniel S.; Valji, Karim

    2015-08-15

    PurposeLocoregional therapy for hepatocellular carcinoma (HCC) can be challenging in patients with a transjugular intrahepatic portosystemic shunt (TIPS). This study compares safety and imaging response of ablation, chemoembolization, radioembolization, and supportive care in patients with both TIPS and HCC.MethodsThis retrospective study included 48 patients who had both a TIPS and a diagnosis of HCC. Twenty-nine of 48 (60 %) underwent treatment for HCC, and 19/48 (40 %) received best supportive care (i.e., symptomatic management only). While etiology of cirrhosis and indication for TIPS were similar between the two groups, treated patients had better baseline liver function (34 vs. 67 % Child-Pugh class C). Tumor characteristics were similar between the two groups. A total of 39 ablations, 17 chemoembolizations, and 10 yttrium-90 radioembolizations were performed on 29 patients.ResultsAblation procedures resulted in low rates of hepatotoxicity and clinical toxicity. Post-embolization/ablation syndrome occurred more frequently in patients undergoing chemoembolization than ablation (47 vs. 15 %). Significant hepatic dysfunction occurred more frequently in the chemoembolization group than the ablation group. Follow-up imaging response showed objective response in 100 % of ablation procedures, 67 % of radioembolization procedures, and 50 % of chemoembolization procedures (p = 0.001). When censored for OLT, patients undergoing treatment survived longer than patients receiving supportive care (2273 v. 439 days, p = 0.001).ConclusionsAblation appears to be safe and efficacious for HCC in patients with TIPS. Catheter-based approaches are associated with potential increased toxicity in this patient population. Chemoembolization appears to be associated with increased toxicity compared to radioembolization.

  18. Management of Transjugular Intrahepatic Portosystemic Shunt (TIPS)-associated Refractory Hepatic Encephalopathy by Shunt Reduction Using the Parallel Technique: Outcomes of a Retrospective Case Series

    SciTech Connect

    Cookson, Daniel T. Zaman, Zubayr; Gordon-Smith, James; Ireland, Hamish M.; Hayes, Peter C.

    2011-02-15

    Purpose: To investigate the reproducibility and technical and clinical success of the parallel technique of transjugular intrahepatic portosystemic shunt (TIPS) reduction in the management of refractory hepatic encephalopathy (HE). Materials and Methods: A 10-mm-diameter self-expanding stent graft and a 5-6-mm-diameter balloon-expandable stent were placed in parallel inside the existing TIPS in 8 patients via a dual unilateral transjugular approach. Changes in portosystemic pressure gradient and HE grade were used as primary end points. Results: TIPS reduction was technically successful in all patients. Mean {+-} standard deviation portosystemic pressure gradient before and after shunt reduction was 4.9 {+-} 3.6 mmHg (range, 0-12 mmHg) and 10.5 {+-} 3.9 mmHg (range, 6-18 mmHg). Duration of follow-up was 137 {+-} 117.8 days (range, 18-326 days). Clinical improvement of HE occurred in 5 patients (62.5%) with resolution of HE in 4 patients (50%). Single episodes of recurrent gastrointestinal hemorrhage occurred in 3 patients (37.5%). These were self-limiting in 2 cases and successfully managed in 1 case by correction of coagulopathy and blood transfusion. Two of these patients (25%) died, one each of renal failure and hepatorenal failure. Conclusion: The parallel technique of TIPS reduction is reproducible and has a high technical success rate. A dual unilateral transjugular approach is advantageous when performing this procedure. The parallel technique allows repeat bidirectional TIPS adjustment and may be of significant clinical benefit in the management of refractory HE.

  19. Transjugular Intrahepatic Porto-Systemic Shunt Placement in a Patient with Left-Lateral Split-Liver Transplant and Mesenterico-Left Portal Vein by Pass Placement

    SciTech Connect

    Miraglia, Roberto Maruzzelli, Luigi; Luca, Angelo

    2011-12-15

    This is a report of a successful placement of a transjugular intrahepatic porto-systemic shunt in a young patient with previous left-lateral, split-liver transplant and mesenterico-left portal vein by pass placement after posttransplant extrahepatic portal vein thrombosis.

  20. Nationwide trends and predictors of inpatient mortality in 83884 transjugular intrahepatic portosystemic shunt

    PubMed Central

    Lee, Edward Wolfgang; Kuei, Andrew; Saab, Sammy; Busuttil, Ronald W; Durazo, Francisco; Han, Steven-Huy; El-Kabany, Mohamed M; McWilliams, Justin P; Kee, Stephen T

    2016-01-01

    AIM: To evaluate and validate the national trends and predictors of in-patient mortality of transjugular intrahepatic portosystemic shunt (TIPS) in 15 years. METHODS: Using the National Inpatient Sample which is a part of Health Cost and Utilization Project, we identified a discharge-weighted national estimate of 83884 TIPS procedures performed in the United States from 1998 to 2012 using international classification of diseases-9 procedural code 39.1. The demographic, hospital and co-morbility data were analyzed using a multivariant analysis. Using multi-nominal logistic regression analysis, we determined predictive factors related to increases in-hospital mortality. Comorbidity measures are in accordance to the Comorbidity Software designed by the Agency for Healthcare Research and Quality. RESULTS: Overall, 12.3% of patients died during hospitalization with downward trend in-hospital mortality with the mean length of stay of 10.8 ± 13.1 d. Notable, African American patients (OR = 1.809 vs Caucasian patients, P < 0.001), transferred patients (OR = 1.347 vs non-transferred, P < 0.001), emergency admissions (OR = 3.032 vs elective cases, P < 0.001), patients in the Northeast region (OR = 1.449 vs West, P < 0.001) had significantly higher odds of in-hospital mortality. Number of diagnoses and number of procedures showed positive correlations with in-hospital death (OR = 1.249 per one increase in number of procedures). Patients diagnosed with acute respiratory failure (OR = 8.246), acute kidney failure (OR = 4.359), hepatic encephalopathy (OR = 2.217) and esophageal variceal bleeding (OR = 2.187) were at considerably higher odds of in-hospital death compared with ascites (OR = 0.136, P < 0.001). Comorbidity measures with the highest odds of in-hospital death were fluid and electrolyte disorders (OR = 2.823), coagulopathy (OR = 2.016), and lymphoma (OR = 1.842). CONCLUSION: The overall mortality of the TIPS procedure is steadily decreasing, though the length of stay

  1. Acquired portosystemic collaterals: anatomy and imaging*

    PubMed Central

    Leite, Andréa Farias de Melo; Mota Jr., Américo; Chagas-Neto, Francisco Abaeté; Teixeira, Sara Reis; Elias Junior, Jorge; Muglia, Valdair Francisco

    2016-01-01

    Portosystemic shunts are enlarged vessels that form collateral pathological pathways between the splanchnic circulation and the systemic circulation. Although their causes are multifactorial, portosystemic shunts all have one mechanism in common-increased portal venous pressure, which diverts the blood flow from the gastrointestinal tract to the systemic circulation. Congenital and acquired collateral pathways have both been described in the literature. The aim of this pictorial essay was to discuss the distinct anatomic and imaging features of portosystemic shunts, as well as to provide a robust method of differentiating between acquired portosystemic shunts and similar pathologies, through the use of illustrations and schematic drawings. Imaging of portosystemic shunts provides subclinical markers of increased portal venous pressure. Therefore, radiologists play a crucial role in the identification of portosystemic shunts. Early detection of portosystemic shunts can allow ample time to perform endovascular shunt operations, which can relieve portal hypertension and prevent acute or chronic complications in at-risk patient populations. PMID:27777479

  2. Pull-Through Technique for Recanalization of Occluded Portosystemic Shunts (TIPS): Technical Note and Review of the Literature

    SciTech Connect

    Tanaka, Toshihiro Guenther, Rolf W. Isfort, Peter; Kichikawa, Kimihiko; Mahnken, Andreas H.

    2011-04-15

    Transjugular intrahepatic portosystemic shunt (TIPS) dysfunction is an important problem after creation of shunts. Most commonly, TIPS recanalization is performed via the jugular vein approach. Occasionally it is difficult to cross the occlusion. We describe a hybrid technique for TIPS revision via a direct transhepatic access combined with a transjugular approach. In two cases, bare metal stents or polytetrafluoroethylene (PTFE)-covered stent grafts had been placed in TIPS tract previously, and they were completely obstructed. The tracts were inaccessible via the jugular vein route alone. In each case, after fluoroscopy or computed tomography-guided transhepatic puncture of the stented segment of the TIPS, a wire was threaded through the shunt and snared into the right jugular vein. The TIPS was revised by balloon angioplasty and additional in-stent placement of PTFE-covered stent grafts. The patients were discharged without any complications. Doppler sonography 6 weeks after TIPS revision confirmed patency in the TIPS tract and the disappearance of ascites. We conclude that this technique is feasible and useful, even in patients with previous PTFE-covered stent graft placement.

  3. Endovascular Management of Refractory Hepatic Encephalopathy Complication of Transjugular Intrahepatic Portosystemic Shunt (TIPS): Comprehensive Review and Clinical Practice Algorithm.

    PubMed

    Pereira, Keith; Carrion, Andres F; Salsamendi, Jason; Doshi, Mehul; Baker, Reginald; Kably, Issam

    2016-02-01

    Transjugular intrahepatic portosystemic shunt (TIPS) has evolved as an effective intervention for treatment of complications of portal hypertension. The use of polytetrafluoroethylene-covered stents have improved the patency of the shunts and diminished the incidence of TIPS dysfunction. However, TIPS-related refractory hepatic encephalopathy (rHE) poses a significant challenge. Approximately 3-7 % of patients with TIPS develop rHE. Refractory hepatic encephalopathy is defined as a recurrent or persistent encephalopathy despite appropriate medical treatment. Hepatic encephalopathy can be an extremely debilitating complication that profoundly affects quality of life. The approach to management of patients with rHE is complex and typically requires collaboration between different specialties. Liver transplantation is the ultimate treatment for rHE; however, the ongoing shortage of organ donation markedly limits this treatment option. Alternative therapies such as shunt occlusion or reduction can control symptoms and serve as a 'bridge' therapy to liver transplantation. Therefore, interventional radiologists play a key role in the management of these patients by offering a variety of endovascular techniques. The purpose of this review is to highlight some of these endovascular techniques and to develop a therapeutic algorithm that can be applied in clinical practice for the management of rHE. PMID:26285910

  4. Primary Implantation of Polyester-Covered Stent-Grafts for Transjugular Intrahepatic Portosystemic Stent Shunts (TIPSS): A Pilot Study

    SciTech Connect

    Cejna, Manfred; Thurnher, Siegfried; Pidlich, Johann; Kaserer, Klaus; Schoder, Maria; Lammer, Johannes

    1999-07-15

    Purpose: To investigate whether placement of a polyester-covered stent-graft increases the primary patency of transjugular intrahepatic portosystemic stent shunts (TIPSS). Methods: Between 1995 and 1997 Cragg Endopro or Passager MIBS stent-grafts were used for the creation of TIPSS in eight male patients, 35-59 years of age (mean 48 years). All patients suffered from recurrent variceal bleeding and/or refractory ascites due to liver cirrhosis. Seven stent-grafts were dilated to a diameter of 10 mm, one to 12 mm. Follow-up was performed with duplex ultrasound, clinical assessment, and angiography. Results: The technical success rate for creation of a TIPSS was 100%. The mean portosystemic pressure gradient decreased from 25 mmHg to 12 mmHg. In seven of eight patients TIPSS dysfunction occurred between 2 days and 3 years after stent-graft placement. In one patient the TIPSS is still primarily patent (224 days after creation). The secondary patency rates are 31 days to 3 years. Conclusion: The primary use of polyester-covered stent-grafts for TIPSS did not increase primary patency rates in our small series.

  5. Bilhemia after trans-jugular intra-hepatic porto-systemic shunt and its management with biliary decompression

    PubMed Central

    Singal, Ashwani K; Kathuria, Manoj K; Malhotra, Advitya; Goodgame, Richard W; Soloway, Roger D

    2009-01-01

    Bilhemia or bile mixing with blood is a rare clinical problem. The clinical presentation is usually transient self-resolving hyperbilirubinemia, progressive and rapidly rising conjugated hyperbilirubinemia, or recurrent cholangitis. Endoscopic retrograde cholangiopancreatography (ERCP) plays an important role in diagnosis and management. Biliary decompression with endoscopic sphincterotomy is useful in treating these patients. If not recognized and treated in time, the condition can be fatal in a significant proportion of patients. This usually occurs after blunt or penetrating hepatic trauma due to a fistulous connection between the biliary radicle and portal or hepatic venous radical. Cases have been described due to iatrogenic trauma such as liver biopsy and percutaneous biliary drainage. However, the occurrence after trans-jugular intra-hepatic porto-systemic shunt (TIPS) is very rare. We report a case of bilhemia presenting as rapidly rising bilirubin after TIPS. The patient was managed successfully with ERCP and removal of a blood clot from the common bile duct. PMID:19653349

  6. A multimodality imaging approach for guiding a modified endovascular coil embolization of a single intrahepatic portosystemic shunt in dogs.

    PubMed

    Knapp, Teja; Navalòn, Iolanda; Medda, Massimo; Pradelli, Danitza; Borgonovo, Simone; Crosta, Cristina; Bussadori, Claudio Maria

    2015-12-01

    Intrahepatic portosystemic shunts (IHPSS) in dogs are aberrant vascular anomalies that connect the portal and the systemic venous vessels. In most of the patients, the surgical approach is unfavourable due to the difficulties in isolating the IHPSS, making the option of a percutaneous transvenous coil embolization (PTCE) one of the safer occlusive procedures. This study describes the treatment of eight dogs with a single IHPSS using a multimodality imaging approach to guide the modified PTCE procedure. This new technique results in a decrease of 71% of the time of the entire procedure with the reduction of 91% in the time required involved the IHPSS identification and in the fluoroscopy exposure time avoiding the need for iodinated contrast agents during the procedure. Moreover, the placement of the catheter before the caval stent ensures its greater stability, enhancing the procedural safety in the phase when the coils are released and avoiding the risk of their dislocation.

  7. Transsplenic portal vein reconstruction-transjugular intrahepatic portosystemic shunt in a patient with portal and splenic vein thrombosis.

    PubMed

    Salsamendi, Jason T; Gortes, Francisco J; Shnayder, Michelle; Doshi, Mehul H; Fan, Ji; Narayanan, Govindarajan

    2016-09-01

    Portal vein thrombosis (PVT) is a potential complication of cirrhosis and can worsen outcomes after liver transplant (LT). Portal vein reconstruction-transjugular intrahepatic portosystemic shunt (PVR-TIPS) can restore flow through the portal vein (PV) and facilitate LT by avoiding complex vascular conduits. We present a case of transsplenic PVR-TIPS in the setting of complete PVT and splenic vein (SV) thrombosis. The patient had a 3-year history of PVT complicated by abdominal pain, ascites, and paraesophageal varices. A SV tributary provided access to the main SV and was punctured percutaneously under ultrasound scan guidance. PV access, PV and SV venoplasty, and TIPS placement were successfully performed without complex techniques. The patient underwent LT with successful end-to-end anastomosis of the PVs. Our case suggests transsplenic PVR-TIPS to be a safe and effective alternative to conventional PVR-TIPS in patients with PVT and SV thrombosis.

  8. Transsplenic portal vein reconstruction-transjugular intrahepatic portosystemic shunt in a patient with portal and splenic vein thrombosis.

    PubMed

    Salsamendi, Jason T; Gortes, Francisco J; Shnayder, Michelle; Doshi, Mehul H; Fan, Ji; Narayanan, Govindarajan

    2016-09-01

    Portal vein thrombosis (PVT) is a potential complication of cirrhosis and can worsen outcomes after liver transplant (LT). Portal vein reconstruction-transjugular intrahepatic portosystemic shunt (PVR-TIPS) can restore flow through the portal vein (PV) and facilitate LT by avoiding complex vascular conduits. We present a case of transsplenic PVR-TIPS in the setting of complete PVT and splenic vein (SV) thrombosis. The patient had a 3-year history of PVT complicated by abdominal pain, ascites, and paraesophageal varices. A SV tributary provided access to the main SV and was punctured percutaneously under ultrasound scan guidance. PV access, PV and SV venoplasty, and TIPS placement were successfully performed without complex techniques. The patient underwent LT with successful end-to-end anastomosis of the PVs. Our case suggests transsplenic PVR-TIPS to be a safe and effective alternative to conventional PVR-TIPS in patients with PVT and SV thrombosis. PMID:27594947

  9. Transjugular Intrahepatic Portosystemic Shunt for Treatment of Cirrhosis-related Chylothorax and Chylous Ascites: Single-institution Retrospective Experience

    SciTech Connect

    Kikolski, Steven G. Aryafar, Hamed Rose, Steven C.; Roberts, Anne C.; Kinney, Thomas B.

    2013-08-01

    PurposeTo investigate the efficacy and safety of the use of transjugular intrahepatic portosystemic shunt (TIPS) creation to treat cirrhosis-related chylous collections (chylothorax and chylous ascites).MethodsWe retrospectively reviewed data from four patients treated for refractory cirrhosis-related chylous collections with TIPS at our institution over an 8 year period.ResultsOne patient had chylothorax, and three patients had concomitant chylothorax and chylous ascites. There were no major complications, and the only procedure-related complications occurred in two patients who had mild, treatable hepatic encephalopathy. All patients had improvement as defined by decreased need for thoracentesis or paracentesis, with postprocedure follow-up ranging from 19 to 491 days.ConclusionTIPS is a safe procedure that is effective in the treatment of cirrhosis-related chylous collections.

  10. Transjugular intrahepatic portosystemic shunt vs endoscopic therapy in preventing variceal rebleeding

    PubMed Central

    Xue, Hui; Zhang, Meng; Pang, Jack XQ; Yan, Fei; Li, Ying-Chao; Lv, Liang-Shan; Yuan, Jia; Palikhe, Muna; Li, Wei-Zhi; Wang, Zhi-Lun

    2012-01-01

    AIM: To compare early use of transjugular intrahepatic portosystemic shunt (TIPS) with endoscopic treatment (ET) for the prophylaxis of recurrent variceal bleeding. METHODS: In-patient data were collected from 190 patients between January 2007 and June 2010 who suffured from variceal bleeding. Patients who were older than 75 years; previously received surgical treatment or endoscopic therapy for variceal bleeding; and complicated with hepatic encephalopathy or hepatic cancer, were excluded from this research. Thirty-five cases lost to follow-up were also excluded. Retrospective analysis was done in 126 eligible cases. Among them, 64 patients received TIPS (TIPS group) while 62 patients received endoscopic therapy (ET group). The relevant data were collected by patient review or telephone calls. The occurrence of rebleeding, hepatic encephalopathy or other complications, survival rate and cost of treatment were compared between the two groups. RESULTS: During the follow-up period (median, 20.7 and 18.7 mo in TIPS and ET groups, respectively), rebleeding from any source occurred in 11 patients in the TIPS group as compared with 31 patients in the ET group (Kaplan-Meier analysis and log-rank test, P = 0.000). Rebleeding rates at any time point (6 wk, 1 year and 2 year) in the TIPS group were lower than in the ET group (Bonferroni correction α’ = α/3). Eight patients in the TIPS group and 16 in the ET group died with the cumulative survival rates of 80.6% and 64.9% (Kaplan-Meier analysis and log-rank test χ2 = 4.864, P = 0.02), respectively. There was no significant difference between the two groups with respect to 6-wk survival rates (Bonferroni correction α’ = α/3). However, significant differences were observed between the two groups in the 1-year survival rates (92% and 79%) and the 2-year survival rates (89% and 64.9%) (Bonferroni correction α’ = α/3). No significant differences were observed between the two treatment groups in the occurrence of

  11. Long-Term Follow-Up After Successful Transjugular Intrahepatic Portosystemic Shunt Placement in a Pediatric Patient with Budd-Chiari Syndrome

    SciTech Connect

    Carnevale, Francisco Cesar Szejnfeld, Denis Moreira, Airton Mota; Gibelli, Nelson; Gregorio, Miguel Angel De; Tannuri, Uenis; Cerri, Giovanni Guido

    2008-11-15

    Orthotopic liver transplantation is the standard of care in patients with Budd-Chiari syndrome (BCS), and transjugular intrahepatic portosystemic shunt (TIPS) has become an important adjunct procedure while the patient is waiting for a liver. No long-term follow up of TIPS in BCS patients has been published in children. We report successful 10-year follow-up of a child with BCS and iatrogenic TIPS dysfunction caused by oral contraceptive use.

  12. Transjugular Intrahepatic Portosystemic Shunt, Mechanical Aspiration Thrombectomy, and Direct Thrombolysis in the Treatment of Acute Portal and Superior Mesenteric Vein Thrombosis

    SciTech Connect

    Ferro, Carlo; Rossi, Umberto G. Bovio, Giulio; Dahamane, M'Hamed; Centanaro, Monica

    2007-09-15

    A patient was admitted because of severe abdominal pain, anorexia, and intestinal bleeding. Contrast-enhanced multidetector computed tomography demonstrated acute portal and superior mesenteric vein thrombosis (PSMVT). The patient was treated percutaneously with transjugular intrahepatic portosystemic shunt (TIPS), mechanical aspiration thrombectomy, and direct thrombolysis, and 1 week after the procedure, complete patency of the portal and superior mesenteric veins was demonstrated. TIPS, mechanical aspiration thrombectomy, and direct thrombolysis together are promising endovascular techniques for the treatment of symptomatic acute PSMVT.

  13. Technical concepts for vascular electromagnetic navigated interventions: aortic in situ fenestration and transjugular intrahepatic porto-systemic shunts.

    PubMed

    Penzkofer, Tobias; Isfort, Peter; Na, Hong-Sik; Wilkmann, Christoph; Osterhues, Sabine; Besting, Andreas; Hänisch, Christoph; Bisplinghoff, Stefan; Jansing, Johannes; von Werder, Sylvie; Gooding, Jorge; de la Fuente, Mathias; Mahnken, Andreas H; Disselhorst-Klug, Catherine; Schmitz-Rode, Thomas; Kuhl, Christiane K; Bruners, Philipp

    2014-04-01

    This work presents concepts for complex endovascular procedures using electromagnetic navigation technology (EMT). Navigation software interfacing a standard commercially available navigation system was developed, featuring registration, electromagnetic field distortion correction, breathing motion detection and gating, and state-of-the-art 3D imaging post processing. Protocols for endovascularly placed, in-situ fenestrated abdominal aortic stent grafts and an EMT guided transjugular intrahepatic portosystemic shunt (TIPSS) creation have been designed. A dedicated set of interventional devices was developed for each of the procedures: For aortic in-situ fenestration a combination of high-porosity stentgrafts, steerable catheters and electromagnetically navigated guidewires was used, for TIPSS a dual-navigated (sheath and stylet) TIPSS-device was designed and manufactured. The developed devices underwent phantom testing, in preparation for animal experiments to prove the feasibility of the approach. Once established, these systems could aid in performing these challenging interventional radiology procedures, exploiting the unique characteristics of electromagnetic navigation and solving multiple of the problems associated with these interventions being performed under X-ray fluoroscopy, such as lacking real-time 3D information or extensive exposure to ionizing radiation.

  14. Increased bone morphogenetic protein 7 signalling in the kidneys of dogs affected with a congenital portosystemic shunt.

    PubMed

    van Dongen, Astrid M; Heuving, Susanne M; Tryfonidou, Marianna A; van Steenbeek, Frank G; Rothuizen, Jan; Penning, Louis C

    2015-05-01

    Dogs with a congenital portosystemic shunt (CPSS) often have enlarged and hyper-filtrating kidneys. Although expression of different growth factors has been well-described in the livers of dogs affected with a CPSS, their expression in the kidneys has yet to be determined. Bone morphogenetic protein 7 (BMP-7), hepatocyte growth factor (HGF) and transforming growth factor (TGF)-β have been implicated in renal development (BMP-7, HGF) or the onset of renal fibrosis (TGF-β). Moreover, BMP-7 and HGF have protective properties in renal fibrosis. In this study, the expression and activity of BMP-7 were investigated in renal biopsies obtained from 13 dogs affected with a CPSS and compared to similar samples from age-matched healthy control dogs. Both quantitative reverse-transcriptase PCR and Western blotting showed up-regulated BMP-7 signalling in kidneys of CPPS-affected dogs. These research findings may help to explain the renal pathology/dysfunction in dogs affected with a CPSS.

  15. Acute Effects of Liver Vein Occlusion by Stent-Graft Placed in Transjugular Intrahepatic Portosystemic Shunt Channel: An Experimental Study

    SciTech Connect

    Keussen, Inger Bergqvist, Lennart; Rissler, Pehr; Cwikiel, Wojciech

    2006-02-15

    The purpose of this study was to evaluate the effects of hepatic vein occlusion by stent-graft used in transjugular intrahepatic portosystemic shunt (TIPS). The experiments were performed in six healthy pigs under general anesthesia. Following percutaneous transhepatic implantation of a port-a-cath in the right hepatic vein, TIPS was created with a stent-graft (Viatorr; W L Gore, Flagstaff, AZ, USA). The outflow from the hepatic vein, blocked by the stent-graft was documented by injection of contrast medium and repeated injections of {sup 99}Tc{sup m}-labeled human serum albumin through the port-a-cath. After 2 weeks, the outflow was re-evaluated, the pigs were sacrificed, and histopathologic examination of the liver was performed. Occlusion of the hepatic vein by a stent-graft had a short and temporary effect on the outflow. Histopathological examination from the affected liver segment showed no divergent pattern. Stent-grafts used in TIPS block the outflow from the liver vein, but do not have a prolonged circulatory effect and do not affect the liver parenchyma.

  16. An Approach to Endovascular and Percutaneous Management of Transjugular Intrahepatic Portosystemic Shunt (TIPS) Dysfunction: A Pictorial Essay and Clinical Practice Algorithm.

    PubMed

    Pereira, Keith; Baker, Reginald; Salsamendi, Jason; Doshi, Mehul; Kably, Issam; Bhatia, Shivank

    2016-05-01

    Transjugular intrahepatic portosystemic shunts (TIPS) have evolved as an effective and durable nonsurgical option in the treatment of portal hypertension (PH). It has been shown to improve survival in decompensated cirrhosis and may also serve as a bridge to liver transplantation. In spite of the technical improvements in the procedure, problems occur with the shunt which jeopardizes effective treatment of the PH. Appropriate management is vital to ensure the longevity of the conduit. Shunt revision techniques include endovascular revision techniques and new shunt creation or, in the appropriate patients, alternative/rescue therapies. The ability of interventional radiologists to restore adequate TIPS function has enormous implications for quality of life with palliation, morbidity/mortality related to variceal bleeding and survival if transplant candidates can live long enough to receive a new liver. As such, it is imperative that these treatment strategies are understood and employed when these patients are encountered. In this review, the restoration of appropriate shunt function using various techniques will be discussed as they apply to a variety of clinical scenarios, based on literature. In addition, illustrative case examples highlighting our experience at an academic tertiary medical center will be included. It is the intent to have this document serve as a concise and informative reference to be used by those who may encounter patients with suboptimal functioning TIPS. PMID:26604117

  17. Transjugular intrahepatic portosystemic shunt creation using a three-dimensional fluoroscopy guidance system in patients with the Budd-Chiari syndrome

    PubMed Central

    Cura, Marco; Shaw, Cathryn J.; Rees, Chet R.

    2015-01-01

    When performed for Budd-Chiari syndrome (BCS), transjugular intrahepatic portosystemic shunt (TIPS) creation can be technically difficult due to hepatic congestion and asymmetric hypertrophy. We present three female patients with decompensated BCS in whom TIPS were created using a three-dimensional fluoroscopy guidance system. On a dedicated workstation using three-dimensional volumes of computed tomography imaging, a virtual needle path was created by the operator extending from the needle entry point (hepatic vein stump or inferior vena cava) to the target portal vein. Subsequently, the virtual needle path was overlaid on the fluoroscopy image for guidance of portal venous cannulation. This technology can be used for TIPS procedures in patients with BCS and other complex TIPS cases, as it may help delimit the trajectory of the needle pass and optimally result in more efficient procedures with decreased radiation dose. PMID:26424949

  18. Evaluation of surgical outcome, complications, and mortality in dogs undergoing preoperative computed tomography angiography for diagnosis of an extrahepatic portosystemic shunt: 124 cases (2005–2014)

    PubMed Central

    Brunson, Benjamin W.; Case, J. Brad; Ellison, Gary W.; Fox-Alvarez, W. Alexander; Kim, Stanley E.; Winter, Matthew; Garcia-Pereira, Fernando L.; Farina, Lisa L.

    2016-01-01

    This study evaluated the safety of preoperative computed tomography angiography (CTA) and its effect on surgical time and clinical outcomes in dogs that underwent surgical correction of a single congenital extrahepatic portosystemic shunt (CEPSS). Patient data were retrospectively collected from medical records and owner communications for 124 dogs with single CEPSS, undergoing preoperative CTA (n = 43) or not (n = 81) which were surgically treated from 2005 to 2014. The frequency of major postoperative complications was 4.7% and 9.9% for the CTA and no CTA groups, respectively (P = 0.49). Mean ± standard deviation (SD) surgical time for the preoperative CTA group was 84 ± 40 min and 81 ± 31 min for the no CTA group (P = 0.28). We conclude that anesthetized preoperative CTA appears to be a safe method for diagnosis and surgical planning in dogs with single CEPSS, and does not appear to affect surgical procedure time, complication rate, or clinical outcome. PMID:26740699

  19. Multidetector-Row Computed Tomography in the Evaluation of Transjugular Intrahepatic Portosystemic Shunt Performed with Expanded-Polytetrafluoroethylene-Covered Stent-Graft

    SciTech Connect

    Fanelli, Fabrizio Bezzi, Mario; Bruni, Antonio; Corona, Mario; Boatta, Emanuele; Lucatelli, Pierleone; Passariello, Roberto

    2011-02-15

    We assessed, in a prospective study, the efficacy of multidetector spiral computed tomography (MDCT) in the evaluation of transjugular intrahepatic portosystemic shunt (TIPS) patency in patients treated with the Viatorr (Gore, Flagstaff, AZ) expanded-polytetrafluoroethylene (e-PTFE)-covered stent-graft. Eighty patients who underwent TIPS procedure using the Viatorr self-expanding e-PTFE stent-graft were evaluated at follow-up of 1, 3, 6, and 12 months with clinical and laboratory tests as well as ultrasound-color Doppler (USCD) imaging. In case of varices, upper gastrointestinal endoscopy was also performed. In addition, the shunt was evaluated using MDCT at 6 and 12 months. In all cases of abnormal findings and discrepancy between MDCT and USCD, invasive control venography was performed. MDCT images were acquired before and after injection of intravenous contrast media on the axial plane and after three-dimensional reconstruction using different algorithms. MDCT was successfully performed in all patients. No artefacts correlated to the Viatorr stent-graft were observed. A missing correlation between UCSD and MDCT was noticed in 20 of 80 (25%) patients. Invasive control venography confirmed shunt patency in 16 (80%) cases and shunt malfunction in 4 (20%) cases. According to these data, MDCT sensitivity was 95.2%; specificity was 96.6%; and positive (PPV) and negative predictive values (NPV) were 90.9 and 98.2%, respectively. USCD sensitivity was 90%; specificity was 75%; and PPV and NPV were 54.5 and 95.7%, respectively. A high correlation (K value = 0.85) between MDCT and invasive control venography was observed. On the basis of these results, MDCT shows superior sensitivity and specificity compared with USCD in those patients in whom TIPS was performed with the Viatorr stent-graft. MDCT can be considered a valid tool in the follow-up of these patients.

  20. Use of the Viatorr Expanded Polytetrafluoroethylene-Covered Stent-Graft for Transjugular Intrahepatic Portosystemic Shunt Creation in Children: Initial Clinical Experience

    SciTech Connect

    Mermuys, Koen; Maleux, Geert Heye, Sam; Lombaerts, Rita; Nevens, Frederik

    2008-07-15

    Four children, three boys and one girl, with a median age of 9 years 8 months, underwent transjugular intrahepatic portosystemic shunt creation with an expanded polytetrafluoroethylene (e-PTFE)-covered nitinol stent. The stent-graft was successfully placed in all four patients without any complication. Clinical and biochemical improvement was noted in all four patients during follow-up. Radiological follow-up with use of duplex ultrasound showed a recurrent stenosis of the shunt 180 days after stent-graft implantation in one patient. This was treated with placement of an additional stent-graft, re-expanding completely the recurrent stenosis. In the other three patients, the stent-graft remained fully patent until the end of the study or until orthotopic liver transplantation. These preliminary results suggest that use of the Viatorr ePTFE-covered stent-graft in children is safe and feasible, with potentially the same high patency rate and improved clinical outcome as reported in adult patients.

  1. Transjugular intrahepatic portosystemic shunting (TIPS) with balloon-expandable and self-expanding stents: Technical and clinical aspects after 3 1/2 years' experience

    SciTech Connect

    Tesdal, I. Kaare; Jaschke, Werner; Buehler, Mathias; Adamus, Ralf; Filser, Thomas; Holm, Eggert; Georgi, Max

    1997-01-15

    Purpose. To evaluate prospectively our experience with transjugular intrahepatic portosystemic shunt (TIPS) using four different metallic stents. Methods. Between November 1991 and April 1995, 57 patients (41 men and 16 women; age 35-72 years, mean 54 years) underwent the TIPS procedure. Techniques for portal vein localization before and during TIPS were fluoroscopy, computed tomography (CT) studies, wedged hepatic venography, arterial portography, and ultrasound. After predilation we deployed balloon-expandable (n=48) and self-expanding (n=45) metallic stents. Fifteen patients underwent variceal embolization. Initial follow-up angiograms (mean 6.9 months, range 3-24 months) were obtained in 39 of these patients. Results. Fifty-three patients (93%) had successful TIPS placement. The mean decrease in portal pressure was 42.7%. Besides fluoroscopy, the most helpful techniques for portal vein localization were venography and CT. Residual stenosis (n=1) and late shortening (n=4) of Wallstents resulted in shunt dysfunction. The technical problems encountered with the Palmaz stent resulted from its lack of flexibility. We combined balloon-expandable and self-expanding stents in 12 patients. The 30-day and late follow-up (mean 11.9 months) percutaneous reintervention rates were 11.3% and 64.2%, respectively. There were no clinically significant complications related to the TIPS insertions. Conclusion. An ideal stent does not exist for TIPS, and the authors recommend combining a Palmaz stent with a flexible self-expanding stent.

  2. Aberrant expression and distribution of enzymes of the urea cycle and other ammonia metabolizing pathways in dogs with congenital portosystemic shunts.

    PubMed

    van Straten, Giora; van Steenbeek, Frank G; Grinwis, Guy C M; Favier, Robert P; Kummeling, Anne; van Gils, Ingrid H; Fieten, Hille; Groot Koerkamp, Marian J A; Holstege, Frank C P; Rothuizen, Jan; Spee, Bart

    2014-01-01

    The detoxification of ammonia occurs mainly through conversion of ammonia to urea in the liver via the urea cycle and glutamine synthesis. Congenital portosystemic shunts (CPSS) in dogs cause hyperammonemia eventually leading to hepatic encephalopathy. In this study, the gene expression of urea cycle enzymes (carbamoylphosphate synthetase (CPS1), ornithine carbamoyltransferase (OTC), argininosuccinate synthetase (ASS1), argininosuccinate lyase (ASL), and arginase (ARG1)), N-acetylglutamate synthase (NAGS), Glutamate dehydrogenase (GLUD1), and glutamate-ammonia ligase (GLUL) was evaluated in dogs with CPSS before and after surgical closure of the shunt. Additionally, immunohistochemistry was performed on urea cycle enzymes and GLUL on liver samples of healthy dogs and dogs with CPSS to investigate a possible zonal distribution of these enzymes within the liver lobule and to investigate possible differences in distribution in dogs with CPSS compared to healthy dogs. Furthermore, the effect of increasing ammonia concentrations on the expression of the urea cycle enzymes was investigated in primary hepatocytes in vitro. Gene-expression of CPS1, OTC, ASL, GLUD1 and NAGS was down regulated in dogs with CPSS and did not normalize after surgical closure of the shunt. In all dogs GLUL distribution was localized pericentrally. CPS1, OTC and ASS1 were localized periportally in healthy dogs, whereas in CPSS dogs, these enzymes lacked a clear zonal distribution. In primary hepatocytes higher ammonia concentrations induced mRNA levels of CPS1. We hypothesize that the reduction in expression of urea cycle enzymes, NAGS and GLUD1 as well as the alterations in zonal distribution in dogs with CPSS may be caused by a developmental arrest of these enzymes during the embryonic or early postnatal phase. PMID:24945279

  3. MELD Score as a Predictor of Early Death in Patients Undergoing Elective Transjugular Intrahepatic Portosystemic Shunt (TIPS) Procedures

    SciTech Connect

    Montgomery, Aaron; Ferral, Hector Vasan, Rajiv; Postoak, Darren W.

    2005-04-15

    Purpose. To Evaluate the MELD score as a predictor of 30-day mortality in patients undergoing elective TIPS procedures. Methods. This was a retrospective, IRB-approved study. The medical records of all patients who underwent a TIPS procedure between May 1, 1999 and June 1, 2003 in a single institution were reviewed. Patients who underwent elective TIPS were selected. Elective TIPS was performed in 119 patients with a mean age of 55.1 ({+-} 9.6) years. The MELD and Child-Pugh scores before TIPS, etiology of cirrhosis, portosystemic gradients before and after TIPS, procedure time, and procedural complications were obtained from the medical records. The MELD and Child-Pugh scores before TIPS were compared between the survivor group (SG) and the early death (EDG) group. The early death rate was calculated for MELD score subgroups (1-10, 11-17, 18-24, and >24). Data were analyzed using the Fisher exact test, chi-square test and independent-sample t-test. A p value of less than 0.05 was considered significant. Results. Technical success rate was 100%. The early death rate was 10.9% (13/119). The mean MELD scores before TIPS were 19.4 ({+-} 5.9) (EDG) and 14 ({+-} 4.2) (SG) (p = 0.025). The early death rate was highest in the pre-TIPS MELD > 24 subgroup. The Child-Pugh scores were 9.0 ({+-} 1.6) (SG) and 9.8 {+-} 1.06 (EDG) (p 0.08). The mean portosystemic gradients before TIPS were 20.5 ({+-} 7.7) mmHg (EDG) and 22.7 ({+-} 7.3) (SG) (p > 1) and the mean portosystemic gradients after TIPS were 6.5 ({+-} 3.5) (EDG) and 6.9 ({+-} 2.4) (SG) (p > 1). The mean procedural times were 95.6 ({+-} 8.4) min (EDG) and 89.2 ({+-} 7.5) min (SG) (p > 1). No early death was attributed to a fatal complication during TIPS. Conclusion. The MELD score is useful in identifying patients at a higher risk of early death after an elective TIPS. On the basis of our results, we do not endorse elective TIPS in patients with MELD scores > 24.

  4. Safety and efficacy of 2-octyl-cyanoacrylate in the management of patients with gastric and duodenal varices who are not candidates for transjugular intrahepatic portosystemic shunts

    PubMed Central

    Burdick, James; Trotter, James F.

    2016-01-01

    Gastric variceal bleeding is associated with significant morbidity and mortality in patients with portal hypertension and cirrhosis. Options are limited for patients who are not candidates for transjugular intrahepatic portosystemic shunts (TIPS). Cyanoacrylate injections have been reported to be efficacious in previous case series. The aim of this retrospective study was to report our single-center experience with the safety and efficacy of 2-octyl-cyanoacrylate in patients who were not TIPS candidates. Electronic medical records were reviewed for 16 patients who underwent a total of 18 esophagogastroduodenoscopies for acute gastric or duodenal variceal bleeding and secondary prophylaxis of gastric varices; 14 patients had cirrhosis with an average Model for End-Stage Liver Disease score of 16, and 2 patients had noncirrhotic portal hypertension. Primary endpoints of the study included early and delayed rebleeding rate, complications, and death or liver transplantation. The rebleeding rate (early or delayed) was 7%, and no complications were found. One death was reported (unrelated to the procedure). In conclusion, 2-octyl-cyanoacrylate is a safe and effective alternative for non-TIPS candidates who present with acute gastric variceal bleeding given its low rebleeding and complication rate. PMID:27695164

  5. Safety and efficacy of 2-octyl-cyanoacrylate in the management of patients with gastric and duodenal varices who are not candidates for transjugular intrahepatic portosystemic shunts

    PubMed Central

    Burdick, James; Trotter, James F.

    2016-01-01

    Gastric variceal bleeding is associated with significant morbidity and mortality in patients with portal hypertension and cirrhosis. Options are limited for patients who are not candidates for transjugular intrahepatic portosystemic shunts (TIPS). Cyanoacrylate injections have been reported to be efficacious in previous case series. The aim of this retrospective study was to report our single-center experience with the safety and efficacy of 2-octyl-cyanoacrylate in patients who were not TIPS candidates. Electronic medical records were reviewed for 16 patients who underwent a total of 18 esophagogastroduodenoscopies for acute gastric or duodenal variceal bleeding and secondary prophylaxis of gastric varices; 14 patients had cirrhosis with an average Model for End-Stage Liver Disease score of 16, and 2 patients had noncirrhotic portal hypertension. Primary endpoints of the study included early and delayed rebleeding rate, complications, and death or liver transplantation. The rebleeding rate (early or delayed) was 7%, and no complications were found. One death was reported (unrelated to the procedure). In conclusion, 2-octyl-cyanoacrylate is a safe and effective alternative for non-TIPS candidates who present with acute gastric variceal bleeding given its low rebleeding and complication rate.

  6. Hypoxia and GABA shunt activation in the pathogenesis of Alzheimer's disease.

    PubMed

    Salminen, Antero; Jouhten, Paula; Sarajärvi, Timo; Haapasalo, Annakaisa; Hiltunen, Mikko

    2016-01-01

    We have previously observed that the conversion of mild cognitive impairment to definitive Alzheimer's disease (AD) is associated with a significant increase in the serum level of 2,4-dihydroxybutyrate (2,4-DHBA). The metabolic generation of 2,4-DHBA is linked to the activation of the γ-aminobutyric acid (GABA) shunt, an alternative energy production pathway activated during cellular stress, when the function of Krebs cycle is compromised. The GABA shunt can be triggered by local hypoperfusion and subsequent hypoxia in AD brains caused by cerebral amyloid angiopathy. Succinic semialdehyde dehydrogenase (SSADH) is a key enzyme in the GABA shunt, converting succinic semialdehyde (SSA) into succinate, a Krebs cycle intermediate. A deficiency of SSADH activity stimulates the conversion of SSA into γ-hydroxybutyrate (GHB), an alternative route from the GABA shunt. GHB can exert not only acute neuroprotective activities but unfortunately also chronic detrimental effects which may lead to cognitive impairment. Subsequently, GHB can be metabolized to 2,4-DHBA and secreted from the brain. Thus, the activation of the GABA shunt and the generation of GHB and 2,4-DHBA can have an important role in the early phase of AD pathogenesis. PMID:26617286

  7. Efficacy of TACE in TIPS Patients: Comparison of Treatment Response to Chemoembolization for Hepatocellular Carcinoma in Patients With and Without a Transjugular Intrahepatic Portosystemic Shunt

    SciTech Connect

    Kuo, Yuo-Chen Kohi, Maureen P. Naeger, David M. Tong, Ricky T. Kolli, K. Pallav Taylor, Andrew G. Laberge, Jeanne M. Kerlan, Robert K. Fidelman, Nicholas

    2013-10-15

    Purpose: To compare treatment response after transarterial chemoembolization (TACE) for hepatocellular carcinoma (HCC) in patients with and without a transjugular intrahepatic portosystemic shunt (TIPS). Materials and Methods: A retrospective review of patients who underwent conventional TACE for HCC between January 2005 and December 2009 identified 10 patients with patent TIPS. From the same time period, 23 patients without TIPS were selected to control for comparable Model for End-Stage Liver Disease and Child-Pugh-Turcotte scores. The two groups showed similar distribution of Barcelona Clinic Liver Cancer and United Network of Organ Sharing stages. Target HCC lesions were evaluated according to the modified response evaluation criteria in solid tumors (mRECIST) guidelines. Transplantation rate, time to tumor progression, and overall survival (OS) were documented. Results: After TACE, the rate of complete response was significantly greater in non-TIPS patients compared with TIPS patients (74 vs. 30 %, p = 0.03). Objective response rate (complete and partial response) trended greater in the non-TIPS group (83 vs. 50 %, p = 0.09). The liver transplantation rate was 80 and 74 % in the TIPS and non-TIPS groups, respectively (p = 1.0). Time to tumor progression was similar (p = 0.47) between the two groups. OS favored the non-TIPS group (p = 0.01) when censored for liver transplantation. Conclusion: TACE is less effective in achieving complete or partial response using mRECIST criteria in TIPS patients compared with those without a TIPS. Nevertheless, similar clinical outcomes may be achieved, particularly in TIPS patients who are liver-transplantation candidates.

  8. Impact of Anatomical, Procedural, and Operator Skill Factors on the Success and Duration of Fluoroscopy-Guided Transjugular Intrahepatic Portosystemic Shunt

    SciTech Connect

    Marquardt, Steffen Rodt, Thomas Rosenthal, Herbert Wacker, Frank Meyer, Bernhard C.

    2015-08-15

    PurposeTo assess the impact of anatomical, procedural, and operator skill factors on the success and duration of fluoroscopy-guided transjugular intrahepatic portoystemic shunt following standard operating procedure (SOP).Material and MethodsDuring a 32-month period, 102 patients underwent transjugular intrahepatic portosystemic shunt creation (TIPS) by two interventional radiologists (IR) following our institutional SOP based on fluoroscopy guidance. Both demographic and procedural data were assessed. The duration of the intervention (D{sub Int}) and of the portal vein puncture (D{sub Punct}) was analyzed depending on the skill level of the IR as well as the anatomic or procedural factors.ResultsIn 99 of the 102 patients, successful TIPS without peri-procedural complications was performed. The mean D{sub Int} (IR1: 77 min; IR2: 51 min, P < 0.005) and the mean D{sub Punct} (IR1: 19 min; IR2: 13 min, P < 0.005) were significantly higher in TIPS performed by IR1 (with 2 years of clinical experience performing TIPS, n = 38) than by IR2 (>10 years of clinical experience performing TIPS, n = 61), (P < 0.005 both, Mann–Whitney U test). D{sub Int} showed a higher correlation with D{sub Punct} for IR2 (R{sup 2} = 0.63) than for IR1 (R{sup 2} = 0.13). There was no significant difference in the D{sub Punct} for both IRs with regard to the success of the wedged portography (P = 0.90), diameter of the portal vein (P = 0.60), central right portal vein length (P = 0.49), or liver function (MELD-Score before the TIPS procedure; P = 0.14).ConclusionTIPS following SOP is safe, fast, and reliable. The only significant factor for shorter D{sub Punct} and D{sub Int} was the clinical experience of the IR. Anatomic variability, successful portography, or liver function did not alter the duration or technical success of TIPS.

  9. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    MedlinePlus

    ... ray or ultrasound equipment, a stent, and a balloon-tipped catheter are used. The equipment typically used ... the stent is in the correct position, the balloon is inflated, expanding the stent into place. The ...

  10. Transjugular intrahepatic portosystemic shunt (TIPS)

    MedlinePlus

    ... serious bleeding. Common causes of portal hypertension are: Alcohol use Blood clots in a vein that flows from the liver to the heart Too much iron in the liver ( hemochromatosis ) Hepatitis B or hepatitis ...

  11. Successful use of a transjugular intrahepatic portosystemic stent shunt to control severe refractory oesophageal variceal haemorrhage in a poor risk patient.

    PubMed Central

    Beales, I. L.; Jackson, J. E.; Rudolf, M.; Arnold, J.

    1993-01-01

    This report describes a 44 year old man with a severe gastrointestinal haemorrhage from oesophageal varices. Bleeding could not be controlled with conservative therapy and sclerotherapy. He was successfully treated with a radiologically guided transjugular intrahepatic stent shunt at a time when his condition was too poor to attempt an open surgical procedure. PMID:8121873

  12. Construction of Transjugular Intrahepatic Portosystemic Shunt: Bare Metal Stent/Stent-graft Combination versus Single Stent-graft, a Prospective Randomized Controlled Study with Long-term Patency and Clinical Analysis

    PubMed Central

    Wang, Chang-Ming; Li, Xuan; Fu, Jun; Luan, Jing-Yuan; Li, Tian-Run; Zhao, Jun; Dong, Guo-Xiang

    2016-01-01

    Background: Balanced adjustment of the portal vein shunt volume during a transjugular intrahepatic portosystemic shunt (TIPS) is critical for maintaining liver perfusion and decreasing the incidence of liver insufficiency. A stent-graft is proved to be superior to a bare metal stent (BMS) for the construction of a TIPS. However, the clinical results of the combination application of stents and stent-grafts have not been determined. This study aimed to compare the technique of using a combination of stents and stent-grafts with using a single stent-graft to construct a TIPS. Methods: From April 2011 to November 2014, a total of fifty patients were randomly assigned to a stents-combination group (Group I, n = 28) or a stent-graft group (Group II, n = 22). Primary patency rates were calculated. Clinical data, including the technical success rate, bleeding control results, incidence of encephalopathy, liver function preservation, and survival rate, were assessed. Results: Technically, the success rate was 100% for both groups. The primary patency rates at 1, 2, and 3 years for Group I were 96%, 84%, and 77%, respectively; for Group II, they were 90%, 90%, and 78%, respectively. The survival rates at 1, 2, and 3 years for Group I were 79%, 74%, and 68%, respectively; for Group II, they were 82%, 82%, and 74%, respectively. The incidence of hepatic encephalopathy was 14.3% for Group I and 13.6% for Group II. The Child-Pugh score in Group I was stable at the end of the follow-up but had significantly increased in Group II (t = −2.474, P = 0.022). Conclusions: The construction of a TIPS with either the single stent-graft or BMS/stent-graft combination is effective for controlling variceal bleeding. The BMS/stent-graft combination technique is superior to the stent-graft technique in terms of hepatic function preservation indicated by the Child-Pugh score. However, considering the clinical results of the TIPS, the two techniques are comparable in their primary shunt

  13. Improved Patency of Transjugular Intrahepatic Portosystemic Shunt: The Efficacy of Cilostazol for the Prevention of Pseudointimal Hyperplasia in Swine TIPS Models

    SciTech Connect

    Park, Sang Woo Cha, In Ho; Kim, Chul Hwan; Jeon, Hae Jeong; Park, Jeong Hee; Hong, Suk Joo; Lee, In Sik

    2007-07-15

    Purpose. To investigate the efficacy of oral administration of cilostazol to inhibit pseudointimal/intimal hyperplasia in swine TIPS models. Methods. Successful TIPS creation was carried out in 11 of 12 healthy young pigs (20-25 kg). In the treatment group (n = 6), both cilostazol and aspirin were administered daily, from the first day of TIPS creation. The control group (n = 5) was administered only aspirin. The animals were followed-up for 2 weeks and then killed. The specimen (including portal vein, hepatic parenchymal tract, hepatic vein, and inferior vena cava) and stents were carefully bisected in a longitudinal fashion. The control group was compared with the treatment group by means of a gross and histologic evaluation of the degree of pseudointimal/intimal hyperplasia in the shunt. Results. At the gross evaluation, the control group showed considerably more pseudointimal/intimal hyperplasia than the treatment group. Using microscopic evaluation, there was a statistically significant difference (p < 0.05) in the mean maximum pseudointimal/intimal hyperplasia thickness between the control group (2.97 {+-} 0.33 mm) and treatment group (0.73 {+-} 0.27 mm). Conclusion. Oral administration of cilostazol may have been effective in reducing pseudointimal/intimal hyperplasia in swine TIPS models.

  14. Pathogenesis, Diagnosis, and Treatment of Hepatic Encephalopathy

    PubMed Central

    Atluri, Dileep K; Prakash, Ravi; Mullen, Kevin D

    2011-01-01

    Hepatic encephalopathy (HE) is a neuropsychiatric disorder seen in patients with advanced liver disease or porto-systemic shunts. Based on etiology and severity of HE, the World Congress of Gastroenterology has divided HE into categories and sub-categories. Many user-friendly computer-based neuropsychiatric tests are being validated for diagnosing covert HE. Currently, emphasis is being given to view HE deficits as a continuous spectrum rather than distinct stages. Ammonia is believed to play crucial role in pathogenesis of HE via astrocyte swelling and cerebral edema. However, evidence has been building up which supports the synergistic role of oxidative stress, inflammation and neurosteroids in pathogenesis of HE. At present, treatment of HE aims at decreasing the production and intestinal absorption of ammonia. But as the role of new pathogenetic mechanisms becomes clear, many potential new treatment strategies may become available for clinician. PMID:25755319

  15. Direct measurement of porto-systemic gradient in a failing Fontan circulation.

    PubMed

    Velpula, Madhavi; Sheron, Nick; Guha, Neill; Salmon, Tony; Hacking, Nigel; Veldtman, Gruschen R

    2011-01-01

    We describe the case history of a 42-year-old man with cardiac cirrhosis, portal hypertension, and life-threatening variceal bleeding after Fontan revision surgery. Direct pressure measurements in the portal vein, though high, demonstrated only a modest portosystemic gradient (PSG), 9 mm Hg. A transjugular intrahepatic portosystemic shunt procedure was performed. This reduced the PSG (3 mm Hg). His bleeding was controlled. The patient's histopathological findings were identical to that previously documented in Fontan patients, raising the question of whether these subdiaphragmatic hemodynamics are representative of the broader failing Fontan population. PMID:21356034

  16. Post-TIPS Hepatic Encephalopathy Treated by Occlusion Balloon-Assisted Retrograde Embolization of a Coexisting Spontaneous Splenorenal Shunt

    SciTech Connect

    Shioyama, Yasukazu; Matsueda, Kiyoshi; Horihata, Koushi; Kimura, Masashi; Nishida, Norifumi; Kishi, Kazushi; Terada, Masaki; Sato, Morio; Yamada, Ryusaku

    1996-11-15

    A 51-year-old man with posthepatitis cirrhosis underwent a transjugular intrahepatic portosystemic shunt (TIPS) for bleeding of recurrent esophageal varices. The patient had a coexisting, spontaneous, splenorenal shunt. He subsequently developed hepatic encephalopathy, presumably due to excessive portosystemic shunting. Since medical management resulted in no significant improvement, the splenorenal shunt was embolized from the jugular vein approach via renal vein access during temporary balloon occlusion. Within a few days, the patient's hepatic encephalopathy resolved. Twelve months later the patient showed no recurrence of encephalopathy and had maintained a patent TIPS.

  17. Restoration of Liver Function and Portosystemic Pressure Gradient after TIPSS and Late TIPSS Occlusion

    SciTech Connect

    Maedler, U.; Hansmann, J.; Duex, M.; Noeldge, G.; Sauer, P.; Richter, G.M.

    2002-03-15

    TIPSS (transjugular intrahepatic portosystemic shunt) may be indicated to control bleeding from esophageal and gastric varicose veins, to reduce ascites, and to treat patients with Budd-Chiari syndrome and veno-occlusive disease. Numerous measures to improve the safety and methodology of the procedure have helped to increase the technical and clinical success. Follow-up of TIPSS patients has revealed shunt stenosis to occur more often in patients with preserved liver function (Child A, Child B). In addition, the extent of liver cirrhosis is the main factor that determines prognosis in the long term. Little is known about the effects of TIPSS with respect to portosystemic hemodynamics. This report deals with a cirrhotic patient who stopped drinking 7 months prior to admission. He received TIPSS to control ascites and recurrent esophageal bleeding. Two years later remarkable hypertrophy of the left liver lobe and shunt occlusion was observed. The portosystemic pressure gradient dropped from 24 mmHg before TIPSS to 11 mmHg and remained stable after shunt occlusion. The Child's B cirrhosis prior to TIPSS turned into Child's A cirrhosis and remained stable during the follow-up period of 32 months. This indicates that liver function of TIPSS patients may recover due to hypertrophy of the remaining non-cirrhotic liver tissue. In addition the hepatic hemodynamics may return to normal. In conclusion, TIPSS cannot cure cirrhosis but its progress may be halted if the cause can be removed. This may result in a normal portosystemic gradient, leading consequently to shunt occlusion.

  18. Ventriculoperitoneal shunting

    MedlinePlus

    The person may need to lie flat for 24 hours the first time a shunt is placed. How long the hospital stay is depends on the reason the shunt is needed. The health care team will ... Follow the provider's instructions about how to take care of ...

  19. Comparison of shunt fraction estimation using transcolonic iodine-123-iodoamphetamine and technetium-99m-pertechnetate in a group of dogs with experimentally-induced chronic biliary cirrhosis

    SciTech Connect

    Koblik, P.D.; Hornof, W.J.; Yen, C.K.; Komtebedde, J.; Breznock, E.; Fisher, P. )

    1991-01-01

    Portosystemic shunt fraction estimation using transcolonic iodine-123-iodoamphetamine (IMP) has been previously validated relative to portal vein macroaggregated albumin injections using an experimental model of cirrhosis. Transcolonic technetium-99m-pertechnetate (TcO4-) has been proposed as an alternative tracer to IMP to study portal circulation in cirrhotic patients. We compared shunt fraction estimates from paired transcolonic IMP and TcO4- studies performed on a group of dogs before and after common bile duct ligation surgery. Pertechnetate over-estimated shunt fraction in 6/7 postoperative studies relative to IMP. A good correlation between the two methods was demonstrated, however, the slope of the regression line was substantially less than 1.0 with TcO4- values reaching 100% at IMP shunt values of approximately 60%. This apparent inability to accurately assess high shunt flows may limit the quantitative aspects of TcO4- studies on patients with severe portosystemic shunting.

  20. Ventriculoperitoneal shunt - discharge

    MedlinePlus

    ... ventriculoperitoneal - discharge; VP shunt - discharge; Shunt revision - discharge; Hydrocephalus shunt placement - discharge ... Your child has hydrocephalus and needed a shunt placed to drain excess fluid and relieve pressure in the brain. This buildup of brain ...

  1. Direct intrahepatic portacaval shunt: An experimental study

    PubMed Central

    Luo, Jian-Jun; Yan, Zhi-Ping; Zhou, Kang-Rong; Qian, Sheng

    2003-01-01

    AIM: To determine the feasibility of creating direct intrahepatic portacaval shunt (DIPS) in swine with puncture under sonographic guidance. METHODS: DIPS was created in 10 domestic swine under sonographic guidance. Liver function, blood ammonia level and portosystemic gradient (PSG) were compared before and after the procedure. Patency of shunt was followed by portography every 7 d after DIPS. RESULTS: DIPS was successfully established in all 10 swine without any complications. One day after procedure the alanine aminotransferase (ALT), aspartate aminotransferase (AST), and blood ammonia level (BAL) of swine rose from 5.40 ± 0.69, 16.00 ± 0.79 and 35.66 ± 4.10 to 34.20 ± 3.46, 59.70 ± 2.22 and 66.94 ± 3.44 respectively (P < 0.05). The PSG decreased from 0.59 ± 0.20 kPa to 0.24 ± 0.11 kPa after DIPS (P < 0.05). The shunt of 10 swine was kept patent from 7-28 d (median patency time was 14 d). CONCLUSION: This initial experience demonstrated that creating intrahepatic portacaval shunt from retrohepatic segment of IVC to portal vein with puncture under sonographic guidance in swine is safe and feasible. Further studies are necessary to perform DIPS in cirrhosis patients. PMID:12532459

  2. Distal splenorenal shunt

    MedlinePlus

    ... shunt procedure; Renal - splenic venous shunt; Warren shunt; Cirrhosis - distal splenorenal; Liver failure - distal splenorenal ... hepatitis Blood clots Certain congenital disorders Primary biliary cirrhosis When blood cannot flow normally through the portal ...

  3. Percutaneous Mesocaval Shunt Creation in a Patient with Chronic Portal and Superior Mesenteric Vein Thrombosis.

    PubMed

    Bercu, Zachary L; Sheth, Sachin B; Noor, Amir; Lookstein, Robert A; Fischman, Aaron M; Nowakowski, F Scott; Kim, Edward; Patel, Rahul S

    2015-10-01

    The creation of a transjugular intrahepatic portosystemic shunt (TIPS) is a critical procedure for the treatment of recurrent variceal bleeding and refractory ascites in the setting of portal hypertension. Chronic portal vein thrombosis remains a relative contraindication to conventional TIPS and options are limited in this scenario. Presented is a novel technique for management of refractory ascites in a patient with hepatitis C cirrhosis and chronic portal and superior mesenteric vein thrombosis secondary to schistosomiasis and lupus anticoagulant utilizing fluoroscopically guided percutaneous mesocaval shunt creation.

  4. Percutaneous Mesocaval Shunt Creation in a Patient with Chronic Portal and Superior Mesenteric Vein Thrombosis

    SciTech Connect

    Bercu, Zachary L. Sheth, Sachin B.; Noor, Amir; Lookstein, Robert A. Fischman, Aaron M. Nowakowski, F. Scott Kim, Edward Patel, Rahul S.

    2015-10-15

    The creation of a transjugular intrahepatic portosystemic shunt (TIPS) is a critical procedure for the treatment of recurrent variceal bleeding and refractory ascites in the setting of portal hypertension. Chronic portal vein thrombosis remains a relative contraindication to conventional TIPS and options are limited in this scenario. Presented is a novel technique for management of refractory ascites in a patient with hepatitis C cirrhosis and chronic portal and superior mesenteric vein thrombosis secondary to schistosomiasis and lupus anticoagulant utilizing fluoroscopically guided percutaneous mesocaval shunt creation.

  5. Ventriculomammary shunt: an unusual ventriculoperitoneal shunt complication.

    PubMed

    Chaudhry, Nauman S; Johnson, Jeremiah N; Morcos, Jacques J

    2015-02-01

    Ventriculoperitoneal (VP) shunt malfunctions are common and can result in significant consequences for patients. Despite the prevalence of breast augmentation surgery and breast surgery for other pathologies, few breast related VP shunt complications have been reported. A 54-year-old woman with hydrocephalus post-subarachnoid hemorrhage returned 1 month after VP shunt placement complaining of painful unilateral breast enlargement. After investigation, it was determined that the distal VP shunt catheter had migrated from the peritoneal cavity into the breast and wrapped around her breast implant. The breast enlargement was the result of cerebrospinal fluid retention. We detail this unusual case and review all breast related VP shunt complications reported in the literature. To avoid breast related complications related to VP shunt procedures, it is important to illicit pre-procedural history regarding breast implants, evade indwelling implants during catheter tunneling and carefully securing the abdominal catheter to prevent retrograde catheter migration to the breast.

  6. Polytetrafluoroethylene sponge syringosubarachnoid shunt.

    PubMed

    Chagla, Aadil S; Kansal, Ritesh; Srikant, Balasubramaniam

    2011-01-01

    Syringomyelia is condition in which a cyst or cavity forms inside the spinal cavity. Its management always remains a difficult. A variety of surgical techniques have been used in management of syringomyelia. Syringosubarachnoid shunt remains an effective method in management of syringomyelia. Shunt tube obstruction remains an important complication of shunt procedure. We describe a novel technique of use of polytetrafluoroethylene sponge shunt for syringosubarachnoid shunt in patient with large syrinx and Chiari 1 malformation. Polytetrafluoroethylene sponge is a non irritant material with multiple porosities that is less susceptible to blockages or kinking. It could provide a good alternative technique in syringosubarachnoid shunting.

  7. Idiopathic Non-Cirrhotic Intrahepatic Portal Hypertension (NCIPH)—Newer Insights into Pathogenesis and Emerging Newer Treatment Options

    PubMed Central

    Goel, Ashish; Elias, Joshua E.; Eapen, Chundamannil E.; Ramakrishna, Banumathi; Elias, Elwyn

    2014-01-01

    Chronic microangiopathy of portal venules results in idiopathic non-cirrhotic intrahepatic portal hypertension (NCIPH). Recent data suggest a role for vasoactive factors of portal venous origin in the pathogenesis of this ‘pure’ vasculopathy of the liver. Enteropathies (often silent), are an important ‘driver’ of this disease. NCIPH is under-recognized and often mis-labeled as cryptogenic cirrhosis. Liver biopsy is needed to prove the diagnosis of NCIPH. In these patients, with advancing disease and increased porto-systemic shunting, the portal venous vasoactive factors bypass the liver filter and contribute to the development of pulmonary vascular endothelial disorders—porto-pulmonary hypertension and hepato-pulmonary syndrome as well as mesangiocapillary glomerulonephritis. Prognosis in NCIPH patients is determined by presence, recognition and management of associated disorders. With better understanding of the pathogenesis of NCIPH, newer treatment options are being explored. Imbalance in ADAMTS 13 (a disintegrin and metalloprotease with thrombospondin type 1 motif, member 13): vWF (von-Willebrand factor) ratio is documented in NCIPH patients and may have a pathogenic role. Therapeutic interventions to correct this imbalance may prove to be important in the management of NCIPH. PMID:25755567

  8. Ventricular shunt infections: immunopathogenesis and clinical management.

    PubMed

    Gutierrez-Murgas, Yenis; Snowden, Jessica N

    2014-11-15

    Ventricular shunts are the most common neurosurgical procedure performed in the United States. This hydrocephalus treatment is often complicated by infection of the device with biofilm-forming bacteria. In this review, we discuss the pathogenesis of shunt infection, as well as the implications of the biofilm formation on treatment and prevention of these infections. Many questions remain, including the contribution of glia and the impact of inflammation on developmental outcomes following infection. Immune responses within the CNS must be carefully regulated to contain infection while minimizing bystander damage; further study is needed to design optimal treatment strategies for these patients.

  9. Percutaneous Retroperitoneal Splenorenal Shunt for Symptomatic Portal Vein Thrombosis After Liver Transplantation.

    PubMed

    Pulitano, C; Rogan, C; Sandroussi, C; Verran, D; McCaughan, G W; Waugh, R; Crawford, M

    2015-08-01

    Acute or recurrent bleeding from ectopic varices is a potentially life-threatening condition in rare patients with extrahepatic complete portal vein thrombosis (PVT) after liver transplantation (LT). In this setting, the role of interventional radiology is very limited and surgical shunts, in particular splenorenal shunts are usually used, despite the high associated mortality. We present the first reports of the clinical use of a new minimally invasive technique, percutaneous retroperitoneal splenorenal shunt (PRESS), in two LT recipients with life-threatening variceal hemorrhage secondary to PVT. Both patients had a successful PRESS using a transplenic approach with resolution of bleeding, avoiding the need for a potentially complicated laparotomy. The PRESS procedure is a useful addition to the interventional armamentarium that can be used in cases unsuitable for surgical shunt, and refractory to endoscopic management. In the future, this technique may be an alternative to surgical shunts as the standard procedure in patients with extra-hepatic PVT, just as the transjugular intrahepatic portosystemic shunt (TIPS) procedure has become for the management of portal hypertension in the absence of PVT. Longer-term follow-up will be needed to establish the long-term success of this procedure. PMID:25980940

  10. Unusual shunt for symptomatic portal vein thrombosis after liver transplantation - Clatworthy revisited.

    PubMed

    Mali, V P; Robless, P A; Aw, M; Loh, D L; Quak, S H; Prabhakaran, K

    2012-06-01

    PV thrombosis is not an uncommon occurrence following pediatric LT. Symptomatic PHT following PV thrombosis is treated medically, surgical portosystemic shunting (mesorex, splenorenal, and mesocaval) being reserved for refractory cases. A 10-yr-old boy suffered recurrent malena and hemorrhagic shock because of chronic PV thrombosis following LT nine yr ago (1999). Extensive work-up failed to localize the bleeding source. The liver function remained normal. Initial attempts at surgical shunts failed owing to thrombosis (mesocaval 2001, splenorenal, inferior mesenteric-left renal vein, splenic-left external iliac vein 2008). In this situation, we performed a Clatworthy shunt by anastomosing the divided lower end of the LCIV to the side of SMV. There was a single, large caliber anastomosis. Post-operatively, the malena stopped completely, and clinically, there was no lower limb edema or encephalopathy. Doppler USG revealed persistence of hepatopetal flow within the portal collaterals. Follow-up at two yr reveals stable hepatic function with a patent shunt. To the best of our knowledge, we are not aware of a Clatworthy shunt being performed in a transplant setting. We reviewed the literature pertaining to this shunt in non-transplant patients with PHT.

  11. Three-dimensional multi-detector row CT portal venography in the evaluation of portosystemic collateral vessels in liver cirrhosis.

    PubMed

    Kang, Heoung Keun; Jeong, Yong Yeon; Choi, Jun Ho; Choi, Song; Chung, Tae Woong; Seo, Jeong Jin; Kim, Jae Kyu; Yoon, Woong; Park, Jin Gyoon

    2002-01-01

    Multi-detector row computed tomography (CT) offers distinct advantages over traditional spiral CT. Multi-detector row CT scanners are faster and allow thinner collimation than single-detector row spiral CT scanners. The use of multi-detector row CT combined with postprocessing of the imaging data with a variety of three-dimensional reformatting techniques (eg, maximum intensity projection, shaded surface display, volume rendering) allows creation of vascular maps whose quality equals or exceeds that of maps created at classic angiography for many applications. Three-dimensional multi-detector row CT portal venography can help determine the extent and location of portosystemic collateral vessels (eg, left gastric vein, short gastric vein, esophageal and paraesophageal varices, splenorenal and gastrorenal shunts, paraumbilical and abdominal wall veins) in patients with liver cirrhosis and is probably the optimal imaging technique in this setting.

  12. Hydrocephalus and Shunts

    MedlinePlus

    ... or anesthesia. When ventricles start to get too big, it is a strong sign that the shunt is not working right. It is important to know that some people (between 5 and 15 percent) with Spina Bilda may have ...

  13. Shunt tube calcification as a late complication of ventriculoperitoneal shunting

    PubMed Central

    Salim, Abubakr Darrag; Elzain, Mohammed Awad; Mohamed, Haddab Ahmed; Ibrahim Zayan, Baha Eldin Mohamed

    2015-01-01

    Shunt calcification is a rare complication of ventriculoperitoneal shunting that occurs years later after the initial operation this condition is rarely reported in literature. Two patients with shunt calcifications were described. The first patient was 17-year-old lady who had congenital hydrocephalus and shunted in the early infancy, she was presented recently complaining of itching of the skin along the shunt track and limitation of neck movement. The patient was then operated with removal of the old peritoneal catheter and replacing it with a new one. The second patient was 17-year-old boy originally was a case of posterior fossa pilocytic astrocytoma associated with obstructive hydrocephalus, he was operated with both shunting for the hydrocephalus and tumor removal, 6 years later he presented with shunt exposure. Calcification of the shunt tube was discovered intraoperatively upon shunt removal. Shunt calcification has been observed mainly in barium-impregnated catheters. Introducing plain silicone-coated shunt tubing may reduce the rate of this condition. The usual complaints of the patients suffering from this condition are pain in the neck and chest wall along the shunt pathway and limitation of the neck movement due to shunt tube tethering, but features of shunt dysfunction and skin irritation above the shunt may be present. In this review, plain X-ray and operative findings showed that the most extensive calcification is present in the neck, where the catheters were subject to heavy mechanical stress. Disturbed calcium and phosphate metabolisms may be involved in this condition. Shunt calcification is a rare condition that occurs due to material aging presenting with features of shunt tethering, dysfunction or overlying skin irritation. Plain X-ray is needed to detect calcification while shunt removal, replacement or endoscopic third ventriculostomy may carry solution for this condition. PMID:26396620

  14. Adrenal pseudotumors on CT due to dilated portosystemic veins

    SciTech Connect

    Mitty, H.M.; Cohen, B.A.; Sprayregen, S.; Schwartz, K.

    1983-10-01

    The adrenal and periadrenal venous systems are part of the portosystemic collateral pathways that may enlarge in portal hypertension. The cross-sectional image of the resulting enlarged venous channels may simulate an adrenal msss. Three examples of such computed tomographic (CT) scans are presented with selective venographic correlation. Patients with portal hypertension and suspected adrenal pathology may require enhanced or dynamic CT scans.

  15. Anatomy of the Portal Vein Bifurcation: Implication for Transjugular Intrahepatic Portal Systemic Shunts

    SciTech Connect

    Kwok, Philip Chong-hei Ng, Wai Fu; Lam, Christine Suk-yee; Tsui, Polly Po; Faruqi, Asma

    2003-06-15

    Purpose: The relationship of the portalvein bifurcation to the liver capsule in Asians, which is an important landmark for transjugular intrahepatic portosystemic shunt, has not previously been described. Methods: The anatomy of the portal vein bifurcation was studied in 70 adult Chinese cadavers; it was characterized as intrahepatic or extrahepatic. The length of the exposed portion of the right and left portal veins was measured when the bifurcation was extrahepatic. Results: The portal vein bifurcation was intrahepatic in 37 cadavers (53%) and extrahepatic in 33 cadavers (47%). The mean length of the right and left extrahepatic portal veins was 0.96 cm and 0.85 cm respectively.Both were less than or equal to 2 cm in 94% of the cadavers with extrahepatic bifurcation. There was no correlation between the presence of cirrhosis and the location of the portal vein bifurcation(p 1.0). There was no statistically significant difference in liver mass in cadavers with either extrahepatic or intrahepatic bifurcation (p =0.40). Conclusions: These findings suggest that fortransjugular intrahepatic portosystemic shunt placement, a portal vein puncture 2 cm from the bifurcation will be safe in most cases.

  16. Insufficient Portal Vein Inflow in Children without Major Shunt Vessels During Living Donor Liver Transplantation.

    PubMed

    Matsuura, Toshiharu; Yoshimaru, Koichiro; Yanagi, Yusuke; Esumi, Genshiro; Hayashida, Makoto; Taguchi, Tomoaki

    2016-01-01

    BACKGROUND Liver cirrhosis is frequently accompanied by insufficient portal vein inflow (IPVF) with large portosystemic shunts. However, pediatric cases often manifested IPVF without any apparent major portosystemic shunts. Although IPVF is a very critical issue, the intraoperative assessment has not been well established. In this study, we reviewed the intraoperative approach and the outcome of the IPVF cases at our department. MATERIAL AND METHODS Eighty-three living donor liver transplantations (LDLT) were performed from 1996 to 2014. The IPVF occurred in 5 cases and necessitated some additional assessments and intraoperative PV flow modulations. We retrospectively reviewed the operative records and analyzed the risk factors and the outcome of the IPVF. RESULTS All 5 IPVF cases were biliary atresia and the mean age at LDLT was 0.74±0.19 years old. The mean recipient PV diameter was 4.3±0.8 mm and the donor IMV patch grafts were applied. To increase the PV inflow, the collaterals around the spleen were ligated in all cases. Intraoperative portal venography was performed in 1 case for selective shunt vessel ligation. In 1 case, the graft was removed and returned to the back table to prevent graft loss during the IPVF. As a result, the final PVF/GV increased to 66.4±20.0 ml/min/100 g. CONCLUSIONS IPVF is a very critical problem. Intraoperative portal venography is helpful and collateral veins ligation is crucial. In some cases, returning the graft to the back table during the PV inflow modulation can prevent graft loss. PMID:27306916

  17. Subgaleal migration of a ventriculoperitoneal shunt.

    PubMed

    Al Hinai, Qasim S; Pawar, Sanjay J; Sharma, Rewati Raman; Devadas, R V

    2006-07-01

    Blockage of a ventriculoperitoneal (VP) shunt is very common. Here, we describe an unusual case of shunt blockage in an infant. He was shunted for hydrocephalus associated with a Dandy-Walker malformation diagnosed at birth. At surgery, the entire VP shunt was found to have migrated into the subgaleal space, which clinically presented as shunt obstruction. We suggest techniques to avoid this rare, but preventable, complication of shunt surgery.

  18. Ascites and abdominal pseudocyst: two uncommon ventriculoperitoneal shunt complications in two cases.

    PubMed

    Comba, Atakan; Gülenç, Nazlı; Çaltepe, Gönül; Dağçınar, Adnan; Yüce, Özlem; Kalaycı, Ayhan Gazi; Ulus, Aykan

    2013-01-01

    Ascites and abdominal pseudocysts (APC) are two rare complications that can occur following placement of a ventriculoperitoneal (VP) shunt. Both complications are characterized by abnormal intraperitoneal cerebrospinal fluid (CSF) collections. Although various factors have been implicated, the exact pathogenesis of the two conditions remains elusive. This paper presents two cases of VP shunt placement resulting from hydrocephaly. The first patient presented with generalized ascites and the other with APC, both of whom were six years old. APC and ascites after VP shunt placement are rare and distinct conditions; therefore, they may require different management strategies.

  19. MRI-Monitored Intra-Shunt Local Agent Delivery of Motexafin Gadolinium: Towards Improving Long-Term Patency of TIPS

    PubMed Central

    Meng, Yanfeng; Zhang, Tong; Willis, Patrick; Le, Thomas; Soriano, Stephanie; Ray, Erik; Valji, Karim; Zhang, Guixiang; Yang, Xiaoming

    2013-01-01

    Background Transjugular intrahepatic portosystemic shunt (TIPS) has become an important and effective interventional procedure in treatment of the complications related to portal hypertension. Although the primary patency of TIPS has been greatly improved due to the clinical application of cover stent-grafts, the long-term patency is still suboptimal. This study was to investigate the feasibility of using magnetic resonance imaging (MRI)-monitored intra-shunt local agent delivery of motexafin gadolinium (MGd) into shunt-vein walls of TIPS. This new technique aimed to ultimately inhibit shuntstenosis of TIPS. Methodology Human umbilical vein smooth muscle cells (SMCs) were incubated with various concentrations of MGd, and then examed by confocal microscopy and T1-map MRI. In addition, the proliferation of MGd-treated cells was evaluated. For in vivo validation, seventeen pigs underwent TIPS. Before placement of the stent, an MGd/trypan-blue mixture was locally delivered, via a microporous balloon, into eleven shunt-hepatic vein walls under dynamic MRI monitoring, while trypan-blue only was locally delivered into six shunt-hepatic vein walls as serve as controls. T1-weighted MRI of the shunt-vein walls was achieved before- and at different time points after agent injections. Contrast-to-noise ratio (CNR) of the shunt-vein wall at each time-point was measured. Shunts were harvested for subsequent histology confirmation. Principal Findings In vitro studies confirmed the capability of SMCs in uptaking MGds in a concentration-dependent fashion, and demonstrated the suppression of cell proliferation by MGds as well. Dynamic MRI displayed MGd/blue penetration into the shunt-vein walls, showing significantly higher CNR of shunt-vein walls on post-delivery images than on pre-delivery images (49.5±9.4 vs 11.2±1.6, P<0.01), which was confirmed by histology. Conclusion Results of this study indicate that MRI-monitored intra-shunt local MGd delivery is feasible and MGd

  20. 30 CFR 56.6401 - Shunting.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Shunting. 56.6401 Section 56.6401 Mineral....6401 Shunting. Except during testing— (a) Electric detonators shall be kept shunted until connected to the blasting line or wired into a blasting round; (b) Wired rounds shall be kept shunted...

  1. To shunt or not to shunt: hydrocephalus and dysraphism.

    PubMed

    Rekate, H L

    1985-01-01

    Objective criteria are available for decision making in children with ventriculomegaly and spina bifida cystica. Figure 29.7 is the evaluation algorithm used in the Hydrocephalus/Myelodysplasia Clinic at Rainbow Babies and Children's Hospital. In children without serious neurosurgical complications such as the Chiari crisis or problems with wound healing, we rely on three reasonably objective measurements for decision making. Head circumference: Measured daily while in hospital and at each visit. If the pattern of head growth crosses multiple percentile lines indicating that the child will be severely megalencephalic, a shunt will be performed. Ultrasonography: Ultrasound determinations are made in the first few days of life, prior to discharge, at 6 weeks of age, and each 6 weeks of age until 6 months. Some measurements of ventricular size (usually CT scan because of a small anterior fontanelle) should be made at age 1 year. Denver Developmental Testing (DDST): These are performed at age 6 weeks and each 6 weeks thereafter. If the child shows significant ventriculomegaly, a shunt is performed. When the results are questionable the decision is delayed and the test repeated in 6 weeks. Whether a shunt is or is not placed in an infant with ventriculomegaly and myelodysplasia, follow-up must remain compulsive. Following shunting, not only should the head circumference stabilize, but the cortical mantle should increase. Often children shunted in this situation fail to show signs of increased intracranial pressure with shunt malfunction and must be followed with serial head circumference measurements as well as ultrasounds and CT scans. If the decision is made not to shunt the child the work of Hall et al. (10) would suggest the possibility that later in life shunts may be needed to prevent scoliosis secondary to hydromyelia. More information is needed as the aggressively treated population become adults. PMID:2415285

  2. [Clinical analysis of pediatric shunt catheter fracture].

    PubMed

    Morishita, Akitsugu; Nagashima, Tatsuya; Kurata, Hiromitsu; Eguchi, Takahiro; Tamaki, Norihiko

    2002-08-01

    Between 1985 and 1998, 415 shunt dysfunctions occurred at Kobe Children's Hospital. The main reasons for shunt revision were obstruction of the catheter, shunt infection, and shunt disconnection. This report presents an analysis of 35 patients (36 cases) who underwent a ventriculoperitoneal (VP) shunt revision because of shunt catheter fracture. All patients were less than 18 years old. We researched their age at the time of revision, site of disruption, postoperative period, shunt system, clinical symptoms, and other factors. The mechanical aspects of shunt catheter fracture are also discussed in this report. The peak time of shunt catheter fracture was the time when children were growing up and were entering elementary school. In other words, when their height was increasing rapidly. At that time, the distal catheter is subjected to traction between the valve and the abdomen at the site of insertion in either the upper or lower direction. However, physical examination of the shunt catheter showed normal range. Additional contributory factors were chronic stimulation at the occipital bone, clavium bone, and costal arch, while movement of the neck and body rotation also caused shunt catheter fracture. These factors all originated from shearing strain at the shunt catheter. We look forward to the introduction of a stronger shunt catheter, because surgical repair time must be minimized to protect the child's mental development. In addition, shearing strain at the shunt catheter needs special attention.

  3. Ventriculoatrial shunt infection due to Cryptococcus neoformans: an ultrastructural and quantitative microbiological study.

    PubMed

    Walsh, T J; Schlegel, R; Moody, M M; Costerton, J W; Salcman, M

    1986-03-01

    A 28-year-old man presented with hydrocephalus due to an infection by Cryptococcus neoformans involving his ventriculoatrial shunt. Ultrastructural studies of the ventriculoatrial shunt demonstrated yeastlike organisms consistent with C. neoformans within a biofilm on the appliance. Quantitative microbiological studies of segments of the shunt demonstrated C. neoformans in a concentration gradient from 9 X 10(6) colony-forming units (CFU)/0.5-cm section involving the ventricular portion of the catheter to 1 X 10(2) CFU/0.5-cm section at the vascular tip. The clinical, microbiological, and ultrastructural data suggest that this cryptococcal infection started as a ventriculitis or encephalitis with extension to the meningeal surface. Future application of these methods may further elucidate the pathogenesis of ventriculoatrial shunt infections.

  4. Liver transplantation in patients with portal vein thrombosis and central portacaval shunts.

    PubMed Central

    Shaked, A; Busuttil, R W

    1991-01-01

    The authors have analyzed the impact of pre-existing portal vein pathology on the outcome of orthotopic liver transplantation. The incidence was high in patients suffering from chronic active hepatitis, hypercoagulable states, trauma or previous dissection of the porta hepatis, and splenectomy. The existence of portal vein thrombosis (23 patients) or surgical central portosystemic shunt (10 patients) was documented by preoperative Doppler sonogram or angiography (26/33), or operative findings of occluded vein (7/33). Successful thrombectomy and dismantling of portacaval shunts were achieved in most cases (24/33). Only nine patients required the placement of an interposition vein graft to the superior mesenteric vein. The intraoperative course was characterized by increased blood loss and coagulopathy, significantly higher than in patients with a patent portal vein. When compared with all liver transplants, the immediate postoperative complication rate was higher for primary nonfunction (33% versus 8%), re-exploration for intraperitoneal bleeding and hematomas, and morbid infections. Rethrombosis rate of thrombectomized veins or vein graft was low (2/33). The mortality rate was 35% in the presence of portal vein thrombosis (PVT) and 30% for portacaval shuct (PCS), both significantly higher than the 12% for other orthotopic liver transplant (OLT) patients. These results are expected to improve with better patient selection, surgical experience, and anticipation of the complex postoperative course. The authors conclude that PVT or the presence of PCS are not contraindications to orthotopic liver transplantation. PMID:1741649

  5. 49 CFR 236.838 - Wire, shunt.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Wire, shunt. 236.838 Section 236.838 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Wire, shunt. A wire forming part of a shunt circuit....

  6. 30 CFR 57.6401 - Shunting.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Shunting. 57.6401 Section 57.6401 Mineral...-Surface and Underground § 57.6401 Shunting. Except during testing— (a) Electric detonators shall be kept shunted until connected to the blasting line or wired into a blasting round; (b) Wired rounds shall...

  7. Disconnection as a cause of ventriculoperitoneal shunt malfunction in multicomponent shunt systems.

    PubMed

    Aldrich, E F; Harmann, P

    The cause of malfunction in 275 consecutive ventriculoperitoneal (VP) shunt revisions over an 8-year period were retrospectively analyzed. In all cases the shunt revised was a multicomponent (Holter) VP shunt. Disconnections in the system accounted for 41 (15%) of the malfunctions. The more distal the connection was from the ventricle, the higher the likelihood of disconnection. Furthermore, occipitally placed shunts had a significantly higher tendency to dislocate than frontally placed shunts.

  8. Students with Shunts: Program Considerations.

    ERIC Educational Resources Information Center

    French, Ron; And Others

    1997-01-01

    Examines how the medical condition of hydrocephalus can affect physical education students and physical education programs, and stresses the need to provide physical educators with information on students' medical conditions. Describes hydrocephalus and its treatment with ventricular peritoneal shunts, and offers suggestions on modifying…

  9. Ventriculoperitoneal shunt perforations of the gastrointestinal tract.

    PubMed

    Thiong'o, Grace Muthoni; Luzzio, Christopher; Albright, A Leland

    2015-07-01

    OBJECT The purposes of this study were to evaluate the frequency with which children presented with ventriculoperitoneal (VP) shunt perforations of the gastrointestinal (GI) tract, to determine the type of shunts that caused the perforations, and to compare the stiffness of perforating catheters with the stiffness of catheters from other manufacturers. METHODS Medical records were reviewed of 197 children who were admitted with VP shunt malfunction. Catheter stiffness was evaluated by measuring relative resistance to cross-sectional compression, resistance to column buckling, and elasticity in longitudinal bending. Catheter frictional force was measured per unit length. RESULTS Six children were identified whose VP shunts had perforated the GI tract; 2 shunts subsequently protruded through the anal orifice, 1 protruded through the oral cavity, and 3 presented with subcutaneous abscesses that tracked upward from the intestine to the chest. All perforating shunts were Chhabra shunts. Catheter stiffness and resistance to bending were greatest with a Medtronic shunt catheter, intermediate with a Codman catheter, and least with a Chhabra catheter. Frictional force was greatest with a Chhabra catheter and least with a Medtronic catheter. CONCLUSIONS The frequency of perforations by Chhabra shunts appears to be higher than the frequency associated with other shunts. The increased frequency does not correlate with their stiffness but may reflect their greater frictional forces.

  10. Shunt regulation electric power system

    NASA Technical Reports Server (NTRS)

    Wright, W. H.; Bless, J. J. (Inventor)

    1971-01-01

    A regulated electric power system having load and return bus lines is described. A plurality of solar cells interconnected in a power supplying relationship and having a power shunt tap point electrically spaced from the bus lines is provided. A power dissipator is connected to the shunt tap point and provides for a controllable dissipation of excess energy supplied by the solar cells. A dissipation driver is coupled to the power dissipator and controls its conductance and dissipation and is also connected to the solar cells in a power taping relationship to derive operating power therefrom. An error signal generator is coupled to the load bus and to a reference signal generator to provide an error output signal which is representative of the difference between the electric parameters existing at the load bus and the reference signal generator. An error amplifier is coupled to the error signal generator and the dissipation driver to provide the driver with controlling signals.

  11. A wireless monitoring system for Hydrocephalus shunts.

    PubMed

    Narayanaswamy, A; Nourani, M; Tamil, L; Bianco, S

    2015-08-01

    Patients with Hydrocephalus are usually treated by diverting the excess Cerebrospinal Fluid (CSF) to other parts of the body using shunts. More than 40 percentage of shunts implanted fail within the first two years. Obstruction in the shunts is one of the major causes of failure (45 percent) and the detection of obstruction reduces the complexity of the revision surgery. This paper describes a proposed wireless monitoring system for clog detection and flow measurement in shunts. A prototype was built using multiple pressure sensors along the shunt catheters for sensing the location of clog and flow rate. Regular monitoring of flow rates can be used to adjust the valve in the shunt to prevent over drainage or under drainage of CSF. The accuracy of the flow measurement is more than 90 percent.

  12. Cell shunt resistance and photovoltaic module performance

    SciTech Connect

    McMahon, T.J.; Basso, T.S.; Rummel, S.R.

    1996-09-01

    Shunt resistance of cells in photovoltaic modules can affect module power output and could indicate flawed manufacturing processes and reliability problems. The authors describe a two-terminal diagnostic method to directly measure the shunt resistance of individual cells in a series-connected module non-intrusively, without deencapsulation. Peak power efficiency vs. light intensity was measured on a 12-cell, series-connected, single crystalline module having relatively high cell shunt resistances. The module was remeasured with 0.5-, 1-, and 2-ohm resistors attached across each cell to simulate shunt resistances of several emerging technologies. Peak power efficiencies decreased dramatically at lower light levels. Using the PSpice circuit simulator, they verified that cell shunt and series resistances can indeed be responsible for the observed peak power efficiency vs. intensity behavior. They discuss the effect of basic cell diode parameters, i.e., shunt resistance, series resistance, and recombination losses, on PV module performance as a function of light intensity.

  13. [Infection of cerebrospinal fluid shunt systems].

    PubMed

    Jiménez-Mejías, Manuel E; García-Cabrera, Emilio

    2008-04-01

    Cerebrospinal fluid (CSF) shunt infection is a cause of considerable morbidity and mortality. Shunt infection is produced mainly during surgery and by surgical wound infection. Staphylococcus spp. (> 50% methicillin-resistant) are the most common causative bacteria, although gram-negative bacilli (10%-25%) and Propionibacterium acnes are becoming increasingly implicated. Shunt malfunction syndrome and fever are the most frequent clinical manifestations, whereas signs of meningeal irritation are uncommon. Other clinical manifestations depend on the location of the distal catheter. CSF should be obtained by puncture of the shunt reservoir or the distal catheter and processed for biochemical analyses, cell count, Gram stain, and aerobic and anaerobic cultures (lengthy incubation). Because of biofilm formation and to avoid recurrences, the recommended treatment is intravenous antibiotics plus removal of all components of the infected shunt, followed by placement of an external drainage catheter and a new shunt. Prophylaxis is important and can include antimicrobial prophylaxis and/or antibiotic-impregnated catheters.

  14. Arterioportal shunts on dynamic computed tomography

    SciTech Connect

    Nakayama, T.; Hiyama, Y.; Ohnishi, K.; Tsuchiya, S.; Kohno, K.; Nakajima, Y.; Okuda, K.

    1983-05-01

    Thirty-two patients, 20 with hepatocelluar carcinoma and 12 with liver cirrhosis, were examined by dynamic computed tomography (CT) using intravenous bolus injection of contrast medium and by celiac angiography. Dynamic CT disclosed arterioportal shunting in four cases of hepatocellular carcinoma and in one of cirrhosis. In three of the former, the arterioportal shunt was adjacent to a mass lesion on CT, suggesting tumor invasion into the portal branch. In one with hepatocellular carcinoma, the shunt was remote from the mass. In the case with cirrhosis, there was no mass. In these last two cases, the shunt might have been caused by prior percutaneous needle puncture. In another case of hepatocellular carcinoma, celiac angiography but not CT demonstrated an arterioportal shunt. Thus, dynamic CT was diagnostic in five of six cases of arteriographically demonstrated arterioportal shunts.

  15. 21 CFR 886.3920 - Aqueous shunt.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Aqueous shunt. 886.3920 Section 886.3920 Food and... OPHTHALMIC DEVICES Prosthetic Devices § 886.3920 Aqueous shunt. (a) Identification. An aqueous shunt is an... Review Guidance of 2/12/90 (K90-1),” and (3) “Aqueous Shunts—510(k) Submissions.”...

  16. Radiological Insertion and Management of Peritoneovenous Shunt

    SciTech Connect

    Bratby, M. J.; Hussain, F. F. Lopez, A. J.

    2007-06-15

    The purpose of the study was to report our experience of the management of complications following the insertion of a peritoneovenous shunt for intractable malignant ascites. From June 1999 to January 2006, 26 patients underwent insertion of a peritoneovenous shunt for ascites by interventional radiologists. We have used ultrasound and shuntography to assist in the diagnosis of the cause of shunt blockage. Successful techniques for the restoration of the shunt function include port- pumping, stripping of any fibrin sheath, and revision of either the venous or peritoneal catheter. The procedure was initially successful in all patients with continued patency until death in 17. A further four patients are still alive with a functioning shunt. There was one rapid postprocedure death resulting from pulmonary edema. Two patients developed pneumothorax, managed successfully with either a chest drain or aspiration. Shunt dysfunction occurred eight times in seven patients. There were five successful revisions in four patients. Overall, shunt patency has been maintained in 80.1% of patients. Shunt dysfunction is seen in a significant number of patients, but successful revision of the shunt can be achieved in the majority.

  17. [Unusual abdominal complication of ventriculoperitoneal shunt].

    PubMed

    Guillén, A; Costa, J M; Castelló, I; Claramunt, E; Cardona, E

    2002-10-01

    The most common complications after CSF shunting to treat hydrocephalus are shunt infection and obstruction. Although ventriculoperitoneal (VP) diversion of the CSF using artificial shunt devices is an accepted method for the management of hydrocephalus, high rates of various complications have been reported, ranging from 24% to 47%. Among these, abdominal complications account for approximately 25%. The incidence of bowel perforation by shunt-catheter is known to be as low as 0.1-0.7%. We describe a case of migration af a peritoneal catheter through a congenital hernia of Morgagni.

  18. Headaches in patients with shunts.

    PubMed

    Rekate, Harold L; Kranz, Dory

    2009-03-01

    Headache is one of the most common afflictions suffered by humans. Headache in patients with a shunt triggers a series of events that includes utilization of expensive technologies and often potentially dangerous surgical intervention. The purpose of this study was to determine the incidence of headaches in patients with shunts and, hopefully, the relationship of those headache disorders to the treatment of hydrocephalus. The Hydrocephalus Association maintains a self-reporting database recorded from individuals treated for hydrocephalus and their families. This database was mined to determine the incidence of severe headaches requiring treatment and interfering with normal life in patients who have been treated for hydrocephalus. There were 1,242 responders between the ages of 19 months and 45 years of age. Of these, 1,233 answered the question, "Do you or your family member suffer from (does your child complain of) frequent or chronic headaches?" This subset forms the basis of this study. Three groups were defined by age: children (19 months-12 years), adolescents (13 years-19 years), and young adults (20 years-45 years). Most respondents were initially treated during infancy (before 18 months of age); 84% of children and 69% of both adolescents and young adults were treated very early in life. Severe headaches became a more frequent problem as the age of the population treated for hydrocephalus increased. In terms of frequency and severity of headaches, direct comparisons with epidemiologic studies of normal populations are difficult because of the limitations of data available in the database. However, it is likely that this population has a higher incidence of severe headaches than normal populations. The cost of management of headaches in this population is very high, and the patients are at risk throughout life. Early treatment decisions have a significant effect on later quality of life. Strategies that lead to normalization of cerebrospinal fluid dynamics

  19. 21 CFR 882.4545 - Shunt system implantation instrument.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... the implantation of cerebrospinal fluid shunts, and includes tunneling instruments for passing shunt components under the skin. (b) Classification. Class I (general controls). When made only of surgical...

  20. 21 CFR 882.4545 - Shunt system implantation instrument.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... the implantation of cerebrospinal fluid shunts, and includes tunneling instruments for passing shunt components under the skin. (b) Classification. Class I (general controls). When made only of surgical...

  1. 49 CFR 236.802 - Shunt.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Shunt. 236.802 Section 236.802 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.802 Shunt. A...

  2. 21 CFR 874.3820 - Endolymphatic shunt.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Endolymphatic shunt. 874.3820 Section 874.3820 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3820 Endolymphatic shunt....

  3. 21 CFR 874.3820 - Endolymphatic shunt.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Endolymphatic shunt. 874.3820 Section 874.3820 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3820 Endolymphatic shunt....

  4. 21 CFR 874.3820 - Endolymphatic shunt.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Endolymphatic shunt. 874.3820 Section 874.3820 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3820 Endolymphatic shunt....

  5. 21 CFR 874.3820 - Endolymphatic shunt.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3820 Endolymphatic shunt. (a) Identification. An endolymphatic shunt is a device that consists of a tube or sheet intended to be implanted to relieve the symptons of vertigo. The device permits the unrestricted flow of excess endolymph from...

  6. 21 CFR 874.3820 - Endolymphatic shunt.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3820 Endolymphatic shunt. (a) Identification. An endolymphatic shunt is a device that consists of a tube or sheet intended to be implanted to relieve the symptons of vertigo. The device permits the unrestricted flow of excess endolymph from...

  7. 49 CFR 234.229 - Shunting sensitivity.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Shunting sensitivity. 234.229 Section 234.229 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION..., Inspection, and Testing Maintenance Standards § 234.229 Shunting sensitivity. Each highway-rail...

  8. 49 CFR 236.56 - Shunting sensitivity.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Shunting sensitivity. 236.56 Section 236.56 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION...: All Systems Track Circuits § 236.56 Shunting sensitivity. Each track circuit controlling home...

  9. 49 CFR 236.56 - Shunting sensitivity.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Shunting sensitivity. 236.56 Section 236.56 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION...: All Systems Track Circuits § 236.56 Shunting sensitivity. Each track circuit controlling home...

  10. 49 CFR 234.229 - Shunting sensitivity.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Shunting sensitivity. 234.229 Section 234.229 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION..., Inspection, and Testing Maintenance Standards § 234.229 Shunting sensitivity. Each highway-rail...

  11. 49 CFR 236.56 - Shunting sensitivity.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Shunting sensitivity. 236.56 Section 236.56 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION...: All Systems Track Circuits § 236.56 Shunting sensitivity. Each track circuit controlling home...

  12. 49 CFR 236.56 - Shunting sensitivity.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Shunting sensitivity. 236.56 Section 236.56 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION...: All Systems Track Circuits § 236.56 Shunting sensitivity. Each track circuit controlling home...

  13. 49 CFR 236.56 - Shunting sensitivity.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Shunting sensitivity. 236.56 Section 236.56 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION...: All Systems Track Circuits § 236.56 Shunting sensitivity. Each track circuit controlling home...

  14. Anthrax Pathogenesis.

    PubMed

    Moayeri, Mahtab; Leppla, Stephen H; Vrentas, Catherine; Pomerantsev, Andrei P; Liu, Shihui

    2015-01-01

    Anthrax is caused by the spore-forming, gram-positive bacterium Bacillus anthracis. The bacterium's major virulence factors are (a) the anthrax toxins and (b) an antiphagocytic polyglutamic capsule. These are encoded by two large plasmids, the former by pXO1 and the latter by pXO2. The expression of both is controlled by the bicarbonate-responsive transcriptional regulator, AtxA. The anthrax toxins are three polypeptides-protective antigen (PA), lethal factor (LF), and edema factor (EF)-that come together in binary combinations to form lethal toxin and edema toxin. PA binds to cellular receptors to translocate LF (a protease) and EF (an adenylate cyclase) into cells. The toxins alter cell signaling pathways in the host to interfere with innate immune responses in early stages of infection and to induce vascular collapse at late stages. This review focuses on the role of anthrax toxins in pathogenesis. Other virulence determinants, as well as vaccines and therapeutics, are briefly discussed.

  15. Shunt failure caused by valve collapse.

    PubMed

    Lundar, T; Langmoen, I A; Hovind, K H

    1991-06-01

    Shunt failure due to collapse of the Mini-Holter valve was observed 13 times in 11 out of 179 children with an implanted Mini-Holter ventriculo-peritoneal (VP) or ventriculo-atrial (VA) shunt during a 10 year period. Intussusception of the proximal or distal end of the valve thus caused a shunt failure rate of 6% of the children in this series. Two children experienced this complication twice. All collapsed valves were part of a VP shunt system. Because of this experience use of the mini valve was abandoned and an adult Holter valve was implanted in children over the age of one month. Breakdown of this particular valve has not occurred in 102 children and two hundred adults with the adult Holter shunt system.

  16. Distal ventriculoperitoneal shunt failure caused by silicone allergy. Case report.

    PubMed

    Hussain, Namath S; Wang, Paul P; James, Carol; Carson, Benjamin S; Avellino, Anthony M

    2005-03-01

    The placement of a ventriculoperitoneal (VP) shunt is the most common form of treatment for hydrocephalus. Although allergic reactions to the silicone in shunt hardware are very rare, the authors describe a case of silicone allergy causing multiple ventricular shunt revisions. A 24-year-old man, who had undergone multiple VP shunt revisions, presented with shunt malfunction caused by allergic reaction of the tissues surrounding the shunt tubing. The patient's existing silicone-based shunt was replaced with a new polyurethane system, including the proximal and distal catheters as well as the valve mechanism. Contrary to recommendations in previous studies of silicone shunt allergies, long-term immunosuppression was not initiated. The patient was followed up for more than 8 years without recurrence of an allergic reaction to the shunt. This outcome indicates that replacing the original silicone-based shunt system with a polyurethane-based system alone is sufficient in the treatment of a silicone shunt allergy.

  17. Transanal protrusion of a ventriculoperitoneal shunt catheter.

    PubMed

    Ozturk, Hulya; Is, Merih; Ozturk, Hayrettin; Kucuk, Adem; Dosoglu, Murat

    2012-11-01

    A two years old boy presented with a transanal protrusion of the ventriculoperitoneal (VP) shunt catheter. A VP shunt was inserted when the boy was six-month-old for congenital hydrocephalus. He was active and neurologically normal, with no signs of meningitis and peritoneal irritation. During laparotomy, the tube was seen entering the sigmoid colon, so the tube was cut at the point where it entered the sigmoid colon. The distal end of the protruding tube was pulled out from the anus. The sigmoid colon was repaired, and a delayed shunt revision was completed. The patient was discharged without abdominal and neurological deterioration.

  18. Transanal protrusion of a ventriculoperitoneal shunt catheter.

    PubMed

    Ozturk, Hulya; Is, Merih; Ozturk, Hayrettin; Kucuk, Adem; Dosoglu, Murat

    2012-11-01

    A two years old boy presented with a transanal protrusion of the ventriculoperitoneal (VP) shunt catheter. A VP shunt was inserted when the boy was six-month-old for congenital hydrocephalus. He was active and neurologically normal, with no signs of meningitis and peritoneal irritation. During laparotomy, the tube was seen entering the sigmoid colon, so the tube was cut at the point where it entered the sigmoid colon. The distal end of the protruding tube was pulled out from the anus. The sigmoid colon was repaired, and a delayed shunt revision was completed. The patient was discharged without abdominal and neurological deterioration. PMID:23146859

  19. Ventriculoperitoneal Shunt Peritoneal Catheter Knot Formation

    PubMed Central

    Ul-Haq, Anwar; Al-Otaibi, Faisal; Alshanafey, Saud; Sabbagh, Mohamed Diya; Al Shail, Essam

    2013-01-01

    The ventriculoperitoneal (VP) shunt is a common procedure in pediatric neurosurgery that carries a risk of complications at cranial and abdominal sites. We report on the case of a child with shunt infection and malfunction. The peritoneal catheter was tethered within the abdominal cavity, precluding its removal. Subsequently, laparoscopic exploration identified a knot at the distal end of the peritoneal catheter around the omentum. A new VP shunt was inserted after the infection was healed. This type of complication occurs rarely, so there are a limited number of case reports in the literature. This report is complemented by a literature review. PMID:24109528

  20. Ventriculo-peritoneal shunt performance under hyperbaric conditions.

    PubMed

    Huang, E T; Hardy, K R; Stubbs, J M; Lowe, R A; Thom, S R

    2000-01-01

    A novice scuba diver with an implanted ventriculo-peritoneal (VP) shunt inquired about the performance characteristics of his shunt while diving. A literature search revealed no information regarding shunt performance under hyperbaric conditions. The manufacturer could not certify that the shunt would function under pressure. Therefore, four VP shunts were tested according to the manufacturer's testing protocol at 1 and 4 atm abs in a multiplace hyperbaric chamber. The pressure (in mm of H2O) required to establish flow through the shunts was recorded. Trials at 1 atm abs (n = 12) and 4 atm abs (n = 12) show that all shunts performed within the pressure range specified by the manufacturer.

  1. Acute Shunt Malfunction Caused by Percutaneous Endoscopic Gastrostomy without Shunt Infection

    PubMed Central

    Choi, Jingyu; Ki, Seung Seog

    2014-01-01

    Percutaneous endoscopic gastrostomy tube placement is often performed in patients with a ventriculoperitoneal shunt and it has been accepted as a safe procedure. The authors report a case of a 50-year-old male who developed acute exacerbation of the hydrocephalus immediately after the percutaneous endoscopic gastrostomy tube placement without any signs of shunt infection, which has not been reported until now. After revision of the intraperitoneal shunt catheter, the sizes of the intracranial ventricles were normalized. PMID:25371790

  2. Syringosubarachnoid shunting using a myringotomy tube

    PubMed Central

    Leschke, Jack M.; Mumert, Michael L.; Kurpad, Shekar N.

    2016-01-01

    Background: Syringomyelia results from obstruction of cerebrospinal fluid (CSF) flow due to a multitude of causes. Often symptoms of pain, weakness, and sensory disturbance are progressive and require surgical treatment. We present here a rare technique for syringosubarachnoid shunting. Case Description: We present the case of a 38-year-old male who suffered a traumatic cervical spinal cord injury due to a motor vehicle accident. With progressive pain and motor decline, a magnetic resonance imaging was obtained and showed a new syrinx extending cervical multiple segments. A unique surgical procedure using a myringotomy tube to shunt CSF into the subarachnoid space was employed in this case. The patient's examination stabilized postoperatively, and at 2 months and 6 months follow-up visits, his strength and sensation continued to improve. Conclusion: We used a myringotomy tube for syringosubarachnoid shunting for the surgical management of a posttraumatic syrinx with good results. This technique minimizes suturing and may minimize shunt-related complications. PMID:26862456

  3. Optimal shunt compensators at nonsinusoidal busbars

    SciTech Connect

    El-Amin, I.M.; Duffuaa, S.O.; Bawah, A.U.

    1995-05-01

    A model for determining an optimal shunt capacitor value at nonsinusoidal busbars combining three basic criteria--maximizing the power factor, minimizing the line losses, and maximizing the transmission efficiency is developed. The choice of the capacitor value is constrained by the values that may cause resonance. This model was solved employing the penalty function approach and the golden Section Search algorithm for solving the linear load case. Furthermore nonlinear loads operating under nonsinusoidal conditions were investigated. The model for the nonlinear load is a two variable problem in L (inductor) and C (capacitor). The Direct Search Polytope algorithm is used. The solution of this model yields an optimal shunt LC compensator for the nonlinear load. However, since there are limitations on the practical values of shunt capacitor, a discretizing approach making use of standard shunt capacitor values is employed to guarantee a solution that can be implemented.

  4. Cell shunt resistance and photovoltaic module performance

    SciTech Connect

    McMahon, T.J.; Basso, T.S.; Rummel, S.R.

    1996-05-01

    Shunt resistance of cells in photovoltaic modules can affect module power output and could indicate flawed manufacturing processes and reliability problems. The authors describe a two-terminal diagnostic method to directly measure the shunt resistance of individual cells in a series-connected module non-intrusively, without deencapsulation. Peak power efficiency vs. light intensity was measured on a 12-cell, series-connected, single crystalline module having relatively high cell shunt resistances. The module was remeasured with 0.5-, 1-, and 2-ohm resistors attached across each cell to simulate shunt resistances of several emerging technologies. Peak power efficiencies decreased dramatically at lower light levels. Using the PSpice circuit simulator, the authors verified that cell shunt and series resistances can indeed be responsible for the observed peak power efficiency vs. intensity behavior. The authors discuss the effect of basic cell diode parameters, i.e., shunt resistance, series resistance, and recombination losses, on PV module performance as a function of light intensity.

  5. Ventriculoperitoneal shunt in cryptococcal meningitis with hydrocephalus.

    PubMed

    Tang, L M

    1990-05-01

    Fourteen patients with cryptococcal meningitis were reviewed. All patients had a ventriculoperitoneal shunt for hydrocephalus. Early recognitions and prompt relief of hydrocephalus were useful for eight patients who showed rapid deterioration of consciousness or signs of cerebral herniation. There was no surgical response in four patients who had had weeks of confusion or mental change. It seems, therefore, that the duration of disturbance of consciousness or change of mentality before shunting is critical in determination of the outcome of the treatment. Ventricular shunting was effective in relieving papilledema in five patients. However, the surgery did not prevent the development of papilledema to optic atrophy and subsequent blindness in two patients. Hence, in addition to hydrocephalus with increased intracranial pressure, conditions such as direct invasion of the optic pathways by Cryptococcus neoformans or optochiasmatic arachnoiditis may be responsible for the visual failure. Ventricular shunting was also helpful in restoring paraparesis in one patient. Of the cerebrospinal fluid determinations, low protein concentration was a favorable indicator for surgery. Of the seven patients who received the surgical procedure before the start of antifungal therapy, four showed a significant improvement despite active infection of the central nervous system. None of the seven patients deteriorated because of the surgical operation. Thus, active stage of cryptococcal meningitis does not contraindicate the necessity of shunting, and premedication with antifungal drugs is unnecessary. Also, no shunt-related morbidity and mortality was seen in this study.

  6. Simulation model for port shunting yards

    NASA Astrophysics Data System (ADS)

    Rusca, A.; Popa, M.; Rosca, E.; Rosca, M.; Dragu, V.; Rusca, F.

    2016-08-01

    Sea ports are important nodes in the supply chain, joining two high capacity transport modes: rail and maritime transport. The huge cargo flows transiting port requires high capacity construction and installation such as berths, large capacity cranes, respectively shunting yards. However, the port shunting yards specificity raises several problems such as: limited access since these are terminus stations for rail network, the in-output of large transit flows of cargo relatively to the scarcity of the departure/arrival of a ship, as well as limited land availability for implementing solutions to serve these flows. It is necessary to identify technological solutions that lead to an answer to these problems. The paper proposed a simulation model developed with ARENA computer simulation software suitable for shunting yards which serve sea ports with access to the rail network. Are investigates the principal aspects of shunting yards and adequate measures to increase their transit capacity. The operation capacity for shunting yards sub-system is assessed taking in consideration the required operating standards and the measure of performance (e.g. waiting time for freight wagons, number of railway line in station, storage area, etc.) of the railway station are computed. The conclusion and results, drawn from simulation, help transports and logistics specialists to test the proposals for improving the port management.

  7. Ventricular gallbladder shunts: an alternative procedure in hydrocephalus.

    PubMed

    West, K W; Turner, M K; Vane, D W; Boaz, J; Kalsbeck, J; Grosfeld, J L

    1987-07-01

    Hydrocephalus is a frequently encountered problem in infancy and is most commonly treated by placement of ventriculoperionteal (VP) or ventriculoatrial (VA) shunts. Other sites for insertion of the distal shunt have included the stomach, ureter, and fallopian tube. This report describes an experience with ventricular gallbladder shunts (VGB) in 25 children performed from 1970 to 1985. There were 13 girls and 12 boys ranging in age from 6 months to 16 years. Diagnosis included meningomyelocoele (7), congenital hydrocephalus (7), postmeningitic complications (5), intracranial tumor (4), and intraventricular hemorrhage (2). Indications for operation included VP shunt infection (15), massive ascites following VP shunt (3), VA shunt infection (4), and distal shunt malfunction due to fibrinous adhesions or cysts (secondary to infection; (3). Three patients had early shunt failure due to proximal obstruction (2) and gallbladder atony (1). Shunt revision was required in two and the atony was successfully treated with cholecystokinin in one. Fourteen shunts remain in place, two patients have been lost to follow-up, and three children died from unrelated causes. Seventy percent of the 20 patients available for long-term follow-up have functional shunts in place. The VGB shunt procedure remains an attractive alternative for patients with hydrocephalus in whom intraperitoneal and intravascular shunts are no longer feasible.

  8. [Glypressin and emergency sclerotherapy, deferred emergency shunt (Warren, portacaval, mesocaval): new tactics in the treatment of severe hemorrhage by esophagogastric varices in cirrhotic patients].

    PubMed

    Huscher, C; Biraghi, M; Chiodini, S; Recher, A; Torri, F; Zamboni, F

    1990-01-01

    Transplenic decompression of esophageal varices by distal splenorenal shunt according to Warren (DSRS) aims to a selective detention of the esophago-gastric varices, also assuring an adequate portal perfusion and hypertensive state of the porto-mesenteric district. The DSRS though, should and must not be performed in emergency as a high mortality rate is registered in all cases of emergency porto-systemic derivations. A mortality risk is reported even during endoscopic sclerosis if performed in emergency compared to the elective procedure. The scope of our study was to test the validity of a new approach of the hemorrhagic cirrhotic patient: the end point was to stop the bleeding with Glypressin and deferred sclerotherapy, associating a selective shunt at 40-60 days. Out of 32 patients with esophago-gastric variceal bleeding, 8 were selected also for derivative surgery. Results show Glypressin as the first and best therapeutic approach. The drug in many cases stops bleeding or at least reduces the blood loss allowing an easier endoscopic sclerosis. Further sclerosis and/or surgical therapy may assure variceal eradication.

  9. Delayed Intracerebral Hemorrhage Secondary to Ventriculoperitoneal Shunt

    PubMed Central

    Ma, Li; Chen, Yi-Li; Yang, Shu-Xu; Wang, Yi-Rong

    2015-01-01

    Abstract The ventriculoperitoneal (VP) shunt is a routine procedure for cerebrospinal fluid (CSF) diversion, and is associated with many complications. A delayed hemorrhage after the VP shunt surgery, however, is quite rare. In this study, we report a case involving late-onset hemorrhage. The 67-year-old male patient with a history of head trauma and brain surgery underwent a VP shunt placement for hydrocephalus. The surgery course was uneventful and no bleeding was revealed in the first computed tomographic (CT) scan after the procedure. However, a massive intraparenchymal and intraventricular hemorrhage occurred 8 h following adjustment of the valve system on the 8th day after surgery. Erosion of the vasculature by catheter cannulation and a sudden reduction of CSF pressure after downregulation of the valve could be one of the possible causes of the intracerebral hemorrhage (ICH). PMID:26632700

  10. Radionuclide demonstration of intrapulmonary shunting in cirrhosis

    SciTech Connect

    Bank, E.R.; Thrall, J.H.; Dantzker, D.R.

    1983-05-01

    The association of hepatic cirrhosis and severe arterial hypoxemia has been well described. Although alterations in ventilatory function may partially account for the hypoxemia, the principal mechanism is thought to be a microangiopathic change in the pulmonary vasculature resulting in intrapulmonary arteriovenous shunting with resultant systemic desaturation. Whole-body radionuclide scans with technetium-99m macroaggregated albumin labeling have been diagnostic of right-to-left shunting by their demonstration of tracer accumulation within the extrapulmonary circulation. A case of severe pulmonary arteriovenous shunting in an alcoholic patient in whom hepatic disease had not been of apparent clinical significance before radionuclide scanning is reported. He did not have cuntaeous angiomata as have all other patients with alcoholic cirrhosis and hypoxemia.

  11. Radionuclide demonstration of intrapulmonary shunting in cirrhosis

    SciTech Connect

    Bank, E.R.; Thrall, J.H.; Dantzker, D.R.

    1983-05-01

    The association of hepatic cirrhosis and severe arterial hypoxemia has been well described. Although alterations in ventilatory function may partially account for the hypoxemia, the principal mechanism is thought to be a microangiopathic change in the pulmonary arteriovenous shunting with resultant systemic desaturation. Whole-body radionuclide scans with technetium-99m macroaggrregated albumin (/sup 99m/Tc MAA) labeling have been diagnostic of right-to-left shunting by their demonstration of tracer accumulation within the extrapulmonary circulation. A case of severe pulmonary arteriovenous shunting in an alcoholic patient in whom hepatic disease had not been of apparent clinical significance before radionuclide scanning is reported. He did not have cutaneous angiomata as have all other patients with alcoholic cirrhosis and hypoxemia.

  12. Seizures in relation to shunt dysfunction in children with meningomyelocele.

    PubMed

    Hack, C H; Enrile, B G; Donat, J F; Kosnik, E

    1990-01-01

    To determine whether seizures are a reliable sign of increased intraventricular pressure in children with shunt-dependent hydrocephalus and meningomyelocele, we performed a retrospective chart review of 346 patients with meningomyelocele and shunt-dependent hydrocephalus. Fifty-one patients had seizures. Seizure episodes were investigated to determine whether they were temporally associated with shunt dysfunction. Episodes of actual or presumed shunt dysfunction were analyzed as to presenting symptoms, ventriculogram, computed tomography scan, and shunt film results. These 51 patients had 129 admissions for possible shunt dysfunction. One hundred one admissions were due to increased intraventricular pressure; nine (9%) of these, had a seizure as one of the presenting symptoms. All of the nine episodes had other common presenting symptoms of shunt dysfunction, such as headache, vomiting, lethargy, or respiratory compromise. We conclude that seizures alone are an inadequate predictor of shunt dysfunction in children with meningomyelocele, but can be seen as one of the presenting symptoms.

  13. [Temporary vascular shunt technique for resource scarce environments].

    PubMed

    Ouattara, N; Mlynski, A; Pierret, C

    2011-10-01

    The purpose of this report is to describe a simple and reproducible technique for temporary vascular shunting. This technique is appropriate only for exceptional situations involving scant resource availability. It is not intended to replace conventional vascular shunting techniques.

  14. Recovery from confabulation after normotensive hydrocephalus shunting.

    PubMed

    Dalla Barba, Gianfranco; Barbera, Claudia; Brazzarola, Marta; Marangoni, Sara

    2016-02-01

    Confabulation, the production of statements and actions that are unintentionally incongruous to the subject's history, background, present and future situation, is observed in several conditions affecting the nervous system, but it has never been described in normotensive hydrocephalus. In this article we report on a patient with normotensive hydrocephalus who suffered from an amnesic-confabulatory syndrome. After hydrocephalus shunting, both amnesia and confabulation cleared up abruptly. We discuss this finding in terms of a possible disconnection of the hippocampus, due to transitory white matter damage, which may have recovered after hydrocephalus shunting.

  15. Role of Glyoxylate Shunt in Oxidative Stress Response.

    PubMed

    Ahn, Sungeun; Jung, Jaejoon; Jang, In-Ae; Madsen, Eugene L; Park, Woojun

    2016-05-27

    The glyoxylate shunt (GS) is a two-step metabolic pathway (isocitrate lyase, aceA; and malate synthase, glcB) that serves as an alternative to the tricarboxylic acid cycle. The GS bypasses the carbon dioxide-producing steps of the tricarboxylic acid cycle and is essential for acetate and fatty acid metabolism in bacteria. GS can be up-regulated under conditions of oxidative stress, antibiotic stress, and host infection, which implies that it plays important but poorly explored roles in stress defense and pathogenesis. In many bacterial species, including Pseudomonas aeruginosa, aceA and glcB are not in an operon, unlike in Escherichia coli In P. aeruginosa, we explored relationships between GS genes and growth, transcription profiles, and biofilm formation. Contrary to our expectations, deletion of aceA in P. aeruginosa improved cell growth under conditions of oxidative and antibiotic stress. Transcriptome data suggested that aceA mutants underwent a metabolic shift toward aerobic denitrification; this was supported by additional evidence, including up-regulation of denitrification-related genes, decreased oxygen consumption without lowering ATP yield, increased production of denitrification intermediates (NO and N2O), and increased cyanide resistance. The aceA mutants also produced a thicker exopolysaccharide layer; that is, a phenotype consistent with aerobic denitrification. A bioinformatic survey across known bacterial genomes showed that only microorganisms capable of aerobic metabolism possess the glyoxylate shunt. This trend is consistent with the hypothesis that the GS plays a previously unrecognized role in allowing bacteria to tolerate oxidative stress.

  16. Role of Glyoxylate Shunt in Oxidative Stress Response.

    PubMed

    Ahn, Sungeun; Jung, Jaejoon; Jang, In-Ae; Madsen, Eugene L; Park, Woojun

    2016-05-27

    The glyoxylate shunt (GS) is a two-step metabolic pathway (isocitrate lyase, aceA; and malate synthase, glcB) that serves as an alternative to the tricarboxylic acid cycle. The GS bypasses the carbon dioxide-producing steps of the tricarboxylic acid cycle and is essential for acetate and fatty acid metabolism in bacteria. GS can be up-regulated under conditions of oxidative stress, antibiotic stress, and host infection, which implies that it plays important but poorly explored roles in stress defense and pathogenesis. In many bacterial species, including Pseudomonas aeruginosa, aceA and glcB are not in an operon, unlike in Escherichia coli In P. aeruginosa, we explored relationships between GS genes and growth, transcription profiles, and biofilm formation. Contrary to our expectations, deletion of aceA in P. aeruginosa improved cell growth under conditions of oxidative and antibiotic stress. Transcriptome data suggested that aceA mutants underwent a metabolic shift toward aerobic denitrification; this was supported by additional evidence, including up-regulation of denitrification-related genes, decreased oxygen consumption without lowering ATP yield, increased production of denitrification intermediates (NO and N2O), and increased cyanide resistance. The aceA mutants also produced a thicker exopolysaccharide layer; that is, a phenotype consistent with aerobic denitrification. A bioinformatic survey across known bacterial genomes showed that only microorganisms capable of aerobic metabolism possess the glyoxylate shunt. This trend is consistent with the hypothesis that the GS plays a previously unrecognized role in allowing bacteria to tolerate oxidative stress. PMID:27036942

  17. Recurrent Breast Cancer in a Patient with a Ventriculoperitoneal Shunt

    PubMed Central

    Copeland-Halperin, Libby R.; Cohen, Robert A.

    2015-01-01

    We report a case of a patient with recurrent infiltrating ductal carcinoma of the breast encasing a ventriculoperitoneal shunt. We also review the current literature regarding reports of breast malignancy around a ventriculoperitoneal shunt, as well as the potential relevance of such shunts to the preoperative evaluation and management of patients with breast cancer. PMID:25648450

  18. Emergency department management of ventriculoperitoneal cerebrospinal fluid shunts.

    PubMed

    Madsen, M A

    1986-11-01

    Emergency physicians must be familiar with VP shunts in order to recognize critical complications associated with these devices. Knowledge of the major types of shunt devices commonly used and the mechanics of those devices allows emergency physicians to evaluate patients with shunts in an orderly manner.

  19. 49 CFR 236.57 - Shunt and fouling wires.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Shunt and fouling wires. 236.57 Section 236.57...: All Systems Track Circuits § 236.57 Shunt and fouling wires. (a) Except as provided in paragraph (b) of this section, shunt wires and fouling wires hereafter installed or replaced shall consist of...

  20. 49 CFR 236.104 - Shunt fouling circuit.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Shunt fouling circuit. 236.104 Section 236.104 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION...: All Systems Inspections and Tests; All Systems § 236.104 Shunt fouling circuit. Shunt fouling...

  1. 49 CFR 236.725 - Circuit, switch shunting.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Circuit, switch shunting. 236.725 Section 236.725 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Circuit, switch shunting. A shunting circuit which is closed through contacts of a switch...

  2. 49 CFR 236.104 - Shunt fouling circuit.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Shunt fouling circuit. 236.104 Section 236.104 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION...: All Systems Inspections and Tests; All Systems § 236.104 Shunt fouling circuit. Shunt fouling...

  3. 49 CFR 236.60 - Switch shunting circuit; use restricted.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Switch shunting circuit; use restricted. 236.60... Instructions: All Systems Track Circuits § 236.60 Switch shunting circuit; use restricted. Switch shunting circuit shall not be hereafter installed, except where tract or control circuit is opened by the...

  4. 49 CFR 236.725 - Circuit, switch shunting.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Circuit, switch shunting. 236.725 Section 236.725 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Circuit, switch shunting. A shunting circuit which is closed through contacts of a switch...

  5. 49 CFR 236.104 - Shunt fouling circuit.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Shunt fouling circuit. 236.104 Section 236.104 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION...: All Systems Inspections and Tests; All Systems § 236.104 Shunt fouling circuit. Shunt fouling...

  6. 49 CFR 236.60 - Switch shunting circuit; use restricted.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Switch shunting circuit; use restricted. 236.60... Instructions: All Systems Track Circuits § 236.60 Switch shunting circuit; use restricted. Switch shunting circuit shall not be hereafter installed, except where tract or control circuit is opened by the...

  7. 49 CFR 236.60 - Switch shunting circuit; use restricted.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Switch shunting circuit; use restricted. 236.60... Instructions: All Systems Track Circuits § 236.60 Switch shunting circuit; use restricted. Switch shunting circuit shall not be hereafter installed, except where tract or control circuit is opened by the...

  8. 49 CFR 236.725 - Circuit, switch shunting.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Circuit, switch shunting. 236.725 Section 236.725 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Circuit, switch shunting. A shunting circuit which is closed through contacts of a switch...

  9. [Intraabdominal metastasis of cerebellar medulloblastoma through ventriculoperitoneal shunt].

    PubMed

    Carrasco Torrents, R; Sancho, M A; Juliá, V; Montaner, A; Costa, J M; Morales, L

    2001-01-01

    We present a 6-year-old girl with cerebellar medulloblastoma causing obstructive hydrocephalus that was treated by ventriculoperitoneal shunting. The patient subsequently underwent surgical excision of the tumor followed by adjuvant craniospinal radiotherapy. Nine months after shunting, multiple intraabdominal metastatic lesions were found. Although the risk is low, ventriculoperitoneal shunting may facilitate the spread of malignant cells.

  10. 49 CFR 236.60 - Switch shunting circuit; use restricted.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Switch shunting circuit; use restricted. 236.60... Instructions: All Systems Track Circuits § 236.60 Switch shunting circuit; use restricted. Switch shunting circuit shall not be hereafter installed, except where tract or control circuit is opened by the...

  11. 49 CFR 236.104 - Shunt fouling circuit.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Shunt fouling circuit. 236.104 Section 236.104 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION...: All Systems Inspections and Tests; All Systems § 236.104 Shunt fouling circuit. Shunt fouling...

  12. 49 CFR 236.725 - Circuit, switch shunting.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Circuit, switch shunting. 236.725 Section 236.725 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Circuit, switch shunting. A shunting circuit which is closed through contacts of a switch...

  13. Treatment of syringomyelia with a syringosubarachnoid shunt.

    PubMed

    Tator, C H; Briceno, C

    1988-02-01

    The surgical results in 40 patients with syringomyelia, treated with a syringosubarachnoid shunt or other procedures are reviewed. The principal indication for surgery was that of significant neurological deterioration. There were 12 patients with idiopathic syringomyelia without tonsillar ectopia, 12 with an associated Chiari malformation, 11 with post-traumatic syringomyelia and five patients with spinal arachnoiditis. There were 38 syringosubarachnoid shunts performed in 35 patients, and an excellent or good result was achieved in 26 patients (74.3%). In terms of the type of syringomyelia, the best results were obtained in the idiopathic group without tonsillar ectopia and in the post-traumatic group. A short duration of pre-operative symptoms favoured a better outcome, and in our opinion, early surgical treatment is indicated for all patients with neurological deterioration. All eight patients in whom a posterior fossa decompression was performed as the initial surgical procedure required a second operation, either a syringosubarachnoid or syringoperitoneal shunt to achieve neurological improvement or stabilization. Thus, the syringosubarachnoid shunt is an effective therapeutic modality for patients with syringomyelia, particularly for the idiopathic and post-traumatic groups. More than one surgical procedure may be required to achieve cessation of deterioration. Overall, excellent or good results were achieved in 29 (72.5%) of the 40 patients.

  14. 49 CFR 234.229 - Shunting sensitivity.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Shunting sensitivity. 234.229 Section 234.229 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... sensitivity. Each highway-rail grade crossing train detection circuit shall detect the application of a...

  15. 49 CFR 234.229 - Shunting sensitivity.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Shunting sensitivity. 234.229 Section 234.229 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... sensitivity. Each highway-rail grade crossing train detection circuit shall detect the application of a...

  16. 49 CFR 234.229 - Shunting sensitivity.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Shunting sensitivity. 234.229 Section 234.229 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... sensitivity. Each highway-rail grade crossing train detection circuit shall detect the application of a...

  17. Episodic ventriculomegaly due to hypernatremia mimicking shunt malfunction: case report.

    PubMed

    Jernigan, Sarah C; Stone, Scellig S D; Aronson, Joshua P; Putman, Melissa; Proctor, Mark R

    2015-10-01

    Patients with shunted hydrocephalus presenting with altered mental status and ventriculomegaly are generally considered to be in shunt failure requiring surgical treatment. The authors describe a case of shunted hydrocephalus secondary to a disseminated neuroectodermal tumor in a pediatric patient in whom rapid fluctuations in sodium levels due to diabetes insipidus repeatedly led to significant changes in ventricle size, with invasively confirmed normal shunt function and low intracranial pressure. This clinical picture exactly mimics shunt malfunction, requires urgent nonsurgical therapy, and underscores the importance of considering serum osmolar abnormalities in the differential diagnosis for ventriculomegaly.

  18. [Cerebrospinal fluid shunts for hydrocephalus and related disorders].

    PubMed

    Ito, Masaki; Houkin, Kiyohiro; Saito, Hisayasu; Shimbo, Daisuke; Motegi, Hiroaki; Kawabori, Masahito; Miyamoto, Michiyuki; Yamauchi, Tomohiro

    2012-10-01

    Cerebrospinal fluid (CSF) shunts are commonly employed to treat patients with hydrocephalus. A large number of papers have been published focusing on complications and failures of CSF shunts. However, there appears to be a paucity of knowledge comprehensively covering both common complications and rare ones. In this systematic review, we surveyed articles about surgical complications of CSF shunts as comprehensively as possible. Quantitative analysis was performed to determine the frequency of well-known complications, mortality and revision rates of CSF shunts. Furthermore, rare complications of CSF shunts have also been reviewed.

  19. Platypnea-Orthodeoxia Syndrome: To Shunt or Not to Shunt, That is the Question.

    PubMed

    Klein, Michael R; Kiefer, Todd L; Velazquez, Eric J

    2016-06-01

    Platypnea-orthodeoxia syndrome is a rare disease defined by dyspnea and deoxygenation, induced by an upright position, and relieved by recumbency. Causes include shunting through a patent foramen ovale and pulmonary arteriovenous malformations. A 79-year-old woman experienced 2 syncopal episodes at rest and presented at another hospital. In the emergency department, she was hypoxic, needing 6 L/min of oxygen. Her chest radiograph showed nothing unusual. Transthoracic echocardiograms with saline microcavitation evaluation were mildly positive early after agitated-saline administration, suggesting intracardiac shunting. She was then transferred to our center. Right-sided heart catheterization revealed no oximetric evidence of intracardiac shunting while the patient was supine and had a low right atrial pressure. However, her oxygen saturation dropped to 78% when she sat up. Repeat transthoracic echocardiography while sitting revealed a dramatically positive early saline microcavitation-uptake into the left side of the heart. Transesophageal echocardiograms showed a patent foramen ovale, with right-to-left shunting highly dependent upon body position. The patient underwent successful percutaneous patent foramen ovale closure, and her oxygen supplementation was suspended. In patients with unexplained or transient hypoxemia in which a cardiac cause is suspected, it is important to evaluate shunting in both the recumbent and upright positions. In this syndrome, elevated right atrial pressure is not necessary for significant right-to-left shunting. Percutaneous closure, if feasible, is first-line therapy in these patients.

  20. Platypnea-Orthodeoxia Syndrome: To Shunt or Not to Shunt, That is the Question

    PubMed Central

    Kiefer, Todd L.; Velazquez, Eric J.

    2016-01-01

    Platypnea-orthodeoxia syndrome is a rare disease defined by dyspnea and deoxygenation, induced by an upright position, and relieved by recumbency. Causes include shunting through a patent foramen ovale and pulmonary arteriovenous malformations. A 79-year-old woman experienced 2 syncopal episodes at rest and presented at another hospital. In the emergency department, she was hypoxic, needing 6 L/min of oxygen. Her chest radiograph showed nothing unusual. Transthoracic echocardiograms with saline microcavitation evaluation were mildly positive early after agitated-saline administration, suggesting intracardiac shunting. She was then transferred to our center. Right-sided heart catheterization revealed no oximetric evidence of intracardiac shunting while the patient was supine and had a low right atrial pressure. However, her oxygen saturation dropped to 78% when she sat up. Repeat transthoracic echocardiography while sitting revealed a dramatically positive early saline microcavitation-uptake into the left side of the heart. Transesophageal echocardiograms showed a patent foramen ovale, with right-to-left shunting highly dependent upon body position. The patient underwent successful percutaneous patent foramen ovale closure, and her oxygen supplementation was suspended. In patients with unexplained or transient hypoxemia in which a cardiac cause is suspected, it is important to evaluate shunting in both the recumbent and upright positions. In this syndrome, elevated right atrial pressure is not necessary for significant right-to-left shunting. Percutaneous closure, if feasible, is first-line therapy in these patients. PMID:27303248

  1. Platypnea-Orthodeoxia Syndrome: To Shunt or Not to Shunt, That is the Question.

    PubMed

    Klein, Michael R; Kiefer, Todd L; Velazquez, Eric J

    2016-06-01

    Platypnea-orthodeoxia syndrome is a rare disease defined by dyspnea and deoxygenation, induced by an upright position, and relieved by recumbency. Causes include shunting through a patent foramen ovale and pulmonary arteriovenous malformations. A 79-year-old woman experienced 2 syncopal episodes at rest and presented at another hospital. In the emergency department, she was hypoxic, needing 6 L/min of oxygen. Her chest radiograph showed nothing unusual. Transthoracic echocardiograms with saline microcavitation evaluation were mildly positive early after agitated-saline administration, suggesting intracardiac shunting. She was then transferred to our center. Right-sided heart catheterization revealed no oximetric evidence of intracardiac shunting while the patient was supine and had a low right atrial pressure. However, her oxygen saturation dropped to 78% when she sat up. Repeat transthoracic echocardiography while sitting revealed a dramatically positive early saline microcavitation-uptake into the left side of the heart. Transesophageal echocardiograms showed a patent foramen ovale, with right-to-left shunting highly dependent upon body position. The patient underwent successful percutaneous patent foramen ovale closure, and her oxygen supplementation was suspended. In patients with unexplained or transient hypoxemia in which a cardiac cause is suspected, it is important to evaluate shunting in both the recumbent and upright positions. In this syndrome, elevated right atrial pressure is not necessary for significant right-to-left shunting. Percutaneous closure, if feasible, is first-line therapy in these patients. PMID:27303248

  2. Premature fractures of platinum-cured Silastic shunts.

    PubMed

    Ramsey, D B; Chadduck, W M

    1992-10-01

    Experience with one unitized ventriculoperitoneal (VP) shunt system has disclosed an unacceptably high rate of premature distal shunt tube fracturing. From March, 1986, to February, 1989, 114 new or replacement unitized VP shunts were placed; the patients were followed through November, 1991. Twenty-two (19.3%) returned with peritoneal limb fractures, with a mean time from shunt implantation to fracture of 31.5 +/- 11.3 months (range 15-62 months). All shunts broke in the neck 1.1-11.2 cm below the valve. Of the 22 cases, there were no instances of infection, previous peritoneal limb revisions, or recognizable iatrogenic shunt injury at placement. These fractures also occurred earlier than the usual time expected for biodegradation of shunt tubing. The Silastic tubing in all of these shunts had been manufactured using a more recent platinum-curing process. This tubing has decreased elastance and is more brittle than tubing cured with the previously used dichlorobenzoyl peroxide (DCBP) catalyst. Our studies suggest that the premature shunt tube fractures were related to changes in physical characteristics of the platinum-cured Silastic tubing. Therefore, the DCBP-cured Silastic is to be considered preferable for shunting products. Neurosurgeons are asked to report recurring patterns of shunt system failure.

  3. Intraparenchymal pericatheter cyst following disconnection of ventriculoperitoneal shunt system.

    PubMed

    Balasubramaniam, S; Tyagi, D K; Sawant, H V

    2013-01-01

    Ventriculoperitoneal (VP) shunt is one of the most commonly performed procedures in neurosurgery, but it is also the procedure, which is most prone to complications. Spread of cerebrospinal fluid (CSF) into the brain parenchyma is a rare complication of VP shunt and can take the form of CSF edema or a porencephalic cyst. We describe a case of a 1½-year-old child who presented to us with seizures. Computed tomography scan revealed pericatheter porencephalic cyst. Surgical exploration revealed a disconnected VP shunt system. Patient was neurologically observed after shunt extraction. He was seizure free and radiological follow-up showed resolution of cyst. Ours is the first case to document the presence of pericatheter cyst following complete disconnection of shunt system. Though shunt revision is the accepted treatment modality, careful neurological observation can be done after shunt removal especially in asymptomatic cases with compensated hydrocephalus.

  4. Passively Shunted Piezoelectric Damping of Centrifugally-Loaded Plates

    NASA Technical Reports Server (NTRS)

    Duffy, Kirsten P.; Provenza, Andrew J.; Trudell, Jeffrey J.; Min, James B.

    2009-01-01

    Researchers at NASA Glenn Research Center have been investigating shunted piezoelectric circuits as potential damping treatments for turbomachinery rotor blades. This effort seeks to determine the effects of centrifugal loading on passively-shunted piezoelectric - damped plates. Passive shunt circuit parameters are optimized for the plate's third bending mode. Tests are performed both non-spinning and in the Dynamic Spin Facility to verify the analysis, and to determine the effectiveness of the damping under centrifugal loading. Results show that a resistive shunt circuit will reduce resonant vibration for this configuration. However, a tuned shunt circuit will be required to achieve the desired damping level. The analysis and testing address several issues with passive shunt circuit implementation in a rotating system, including piezoelectric material integrity under centrifugal loading, shunt circuit implementation, and tip mode damping.

  5. Shunt tube problems due to placement of valves on the chest wall--three case reports.

    PubMed

    Tsurushima, H; Harakuni, T; Saito, A; Hyodo, A; Yoshii, Y

    2000-06-01

    Programmable valves are often used for ventriculoperitoneal (VP) shunts with the shunt valve positioned on the chest wall. Three cases of shunt problems occurred due to placement of the valve on the chest wall. A 43-year-old male was treated with a VP shunt, and suffered shunt malfunction due to dislocation of the ventricular tube. A 21-year-old male was treated with a VP shunt, and suffered shunt malfunction due to disconnection of the shunt tube. A 4-day-old female neonate was treated with a VP shunt, and suffered migration of the shunt valve. The shunt system has two anchor sites on the head and chest wall, with the neck between the two anchor sites. High tension is sometimes caused in the shunt tube between the two points due to movement of the neck or growth, and may induce such dislocation and disconnection of the shunt tube. We recommend a longer shunt tube in such cases.

  6. Gender and diurnal effects on specific open-field behavioral patterns in the portacaval shunted rat.

    PubMed

    Theander, B; Apelqvist, G; Bugge, M; Andersson, G; Hindfelt, B; Bengtsson, F

    1997-03-01

    Hepatic encephalopathy (HE) is a frequently observed neuropsychiatric syndrome with unknown pathogenesis in patients suffering from chronic liver failure. The portacaval shunted (PCS) rat has been extensively used as an experimental model for HE and for studying the effects of portal-systemic shunting. Previous behavioral studies on PCS rats have shown a number of abnormalities but there is no consensus about which abnormalities are characteristic. We therefore made a thorough descriptive study of 100 male and female PCS rats and sham-operated controls four to six weeks after the shunting procedure in an open field. The frequency, duration and average time sequence of various kinds of defined spontaneous behavioral patterns were investigated during both night and day in order to assess behavioral differences between PCS rats and sham-operated controls. The results indicate differences especially regarding motor exploratory behaviors such as forward locomotion and rearing. There were also differences in eating and sniffing behaviors. Our results show that the overall behavioral alteration seen in PCS rats compared to sham-operated controls is that of hypoactivity.

  7. Free floating ventricular shunt catheter between lateral ventricles: a case report of an unusual ventriculoperitoneal shunt complication.

    PubMed

    Erol, Fatih Serhat; Cakin, Hakan; Ozturk, Sait; Donmez, Osman; Kaplan, Metin

    2013-01-01

    Ventriculoperitoneal (VP) shunt proximal tip disconnection is rarely seen as a shunt complication. Shunt dysfunction and hydrocephaly can develop due to this disconnection. Presented here is a case of a disconnection of the ventricular catheter from the shunt valve, which passed between both lateral ventricles by free floating in the brain CT. The patient was operated on for hydrocephaly. The dysfunctional shunt valve and peritoneal catheter were removed and a new VP shunt system was implemented. Although some publications report that the ventricular catheter can be disconnected from the shunt valve, can adhere to the intraventricular structures, and can be a source of infection, no studies similar to the current case were found in the literature reporting a free floating ventricular catheter between the lateral ventricles.

  8. Fatal cardiopulmonary complications in children treated with ventriculoatrial shunts.

    PubMed

    Lundar, T; Langmoen, I A; Hovind, K H

    1991-08-01

    During the years from 1965 to 1986, 716 children underwent a total of 2065 shunt procedures in our department. Of these, 1298 were ventriculoatrial (VA). Until 1979, Pudenz VA shunts were almost exclusively used as the primary procedure as well as in revisions. Since 1980, mini-Holter VA shunts have been implanted as a second choice, usually in cases with repeated distal failure in ventriculoperitoneal (VP) shunts. Observation time for children with VA shunts is therefore from 10 to 23 years for the great majority. The cumulative death rate for all patients is 24% (175/716), 9% (64/716) being tumor patients who eventually died as a result of their neoplasm. Most of the other deaths were caused by shunt infection or occurred in a group of children where shunts had been implanted for palliative reasons and where follow-up was only sporadic. Among the 450 children with VA shunts, 15 fatal complications occurred that were directly related to the atrial catheter, resulting in an accumulated incidence of 3% of such serious side effects from VA shunting. Three of these 15 fatal cases presented with nonspecific signs of cardiopulmonary failure following 10-21 years' shunting, and they died from irreversible pulmonary hypertension within a few months. A fourth case of late cor pulmonale has done unexpectedly well and has improved considerably while receiving anticoagulant therapy for over a period of 3 years.

  9. Who Needs a Revision? 20 Years of Cambridge Shunt Lab.

    PubMed

    Czosnyka, Zofia; Czosnyka, Marek; Pickard, John D; Chari, Aswin

    2016-01-01

    Shunt testing independent of manufacturers provides knowledge that can significantly improve the management of patients with hydrocephalus. The Cambridge Shunt Evaluation Laboratory was created 20 years ago. Thanks to financial support from the Department of Health (1993-1998), all shunts in use in the UK were systematically evaluated, with "blue reports" being published. Later new devices were tested as they appeared in public domain.Twenty-six models have been evaluated. The majority of the valves had a non-physiologically low hydrodynamic resistance that may result in over-drainage, both related to posture and during nocturnal cerebral vasogenic waves. A long distal catheter increases the resistance of these valves by 100-200 %. Drainage through valves without a siphon-preventing mechanism is very sensitive to body posture. Shunts with siphon-preventing accessories offer a reasonable resistance to negative outlet pressure. Bench parameters were used to test shunt performance in vivo using infusion tests. A criterion for correctly performing a shunt procedure was established. Pressure measured in the shunt prechamber during the plateau phase of infusion should not remain more than 5 mmHg above the le shunt's operating pressure plus hydrodynamic resistance of the valve multiplied by the infusion rate. "Critical levels" for every shunt and every performance level have been used in the shunt testing wizard of ICM+ software.

  10. Laparoscopically assisted ventriculoperitoneal shunt placement: a prospective randomized controlled trial.

    PubMed

    Schucht, Philippe; Banz, Vanessa; Trochsler, Markus; Iff, Samuel; Krähenbühl, Anna Katharina; Reinert, Michael; Beck, Jürgen; Raabe, Andreas; Candinas, Daniel; Kuhlen, Dominique; Mariani, Luigi

    2015-05-01

    OBJECT In ventriculoperitoneal (VP) shunt surgery, laparoscopic assistance can be used for placement of the peritoneal catheter. Until now, the efficacy of laparoscopic shunt placement has been investigated only in retrospective and nonrandomized prospective studies, which have reported decreased distal shunt dysfunction rates in patients undergoing laparascopic placement compared with mini-laparotomy cohorts. In this randomized controlled trial the authors compared rates of shunt failure in patients who underwent laparoscopic surgery for peritoneal catheter placement with rates in patients who underwent traditional mini-laparotomy. METHODS One hundred twenty patients scheduled for VP shunt surgery were randomized to laparoscopic surgery or mini-laparotomy for insertion of the peritoneal catheter. The primary endpoint was the rate of overall shunt complication or failure within the first 12 months after surgery. Secondary endpoints were distal shunt failure, overall complication/ failure, duration of surgery and hospitalization, and morbidity. RESULTS The overall shunt complication/failure rate was 15% (9 of 60 cases) in the laparoscopic group and 18.3% (11 of 60 cases) in the mini-laparotomy group (p = 0.404). Patients in the laparoscopic group had no distal shunt failures; in contrast, 5 (8%) of 60 patients in the mini-laparotomy group experienced distal shunt failure (p = 0.029). Intraoperative complications occurred in 2 patients (both in the laparoscopic group), and abdominal pain led to catheter removal in 1 patient per group. Infections occurred in 1 patient in the laparoscopic group and 3 in the mini-laparotomy group. The mean durations of surgery and hospitalization were similar in the 2 groups. CONCLUSIONS While overall shunt failure rates were similar in the 2 groups, the use of laparoscopic shunt placement significantly reduced the rate of distal shunt failure compared with mini-laparotomy.

  11. Incisional Hernia Following Ventriculoperitoneal Shunt Positioning

    PubMed Central

    Bonatti, Matteo; Vezzali, Norberto; Frena, Antonio; Bonatti, Giampietro

    2016-01-01

    Incisional hernia represents a rare complication after ventriculoperitoneal shunt positioning due to failure of the fascial suture in the site of abdominal entrance of ventriculoperitoneal catheter. Clinical presentation can be extremely variable, according to patient’s performance status, herniated material constitution (i.e. mesenteric fat, bowel loops or both) and complication occurrence (e.g. strangulation or intestinal obstruction). Early diagnosis is fundamental in order to surgically repair the defect and prevent further complications. We present the case of a paucisymptomatic incisional hernia following ventriculoperitoneal shunt positioning. Diagnosis was made by means of ultrasound and confirmed by means of computed tomography. The patient was successfully managed by means of surgical repositioning of herniated loop and re-suture. PMID:27761180

  12. Quantitative evaluation fo cerebrospinal fluid shunt flow

    SciTech Connect

    Chervu, S.; Chervu, L.R.; Vallabhajosyula, B.; Milstein, D.M.; Shapiro, K.M.; Shulman, K.; Blaufox, M.D.

    1984-01-01

    The authors describe a rigorous method for measuring the flow of cerebrospinal fluid (CSF) in shunt circuits implanted for the relief of obstructive hydrocephalus. Clearance of radioactivity for several calibrated flow rates was determined with a Harvard infusion pump by injecting the Rickham reservoir of a Rickham-Holter valve system with 100 ..mu..Ci of Tc-99m as pertechnetate. The elliptical and the cylindrical Holter valves used as adjunct valves with the Rickham reservoir yielded two different regression lines when the clearances were plotted against flow rats. The experimental regression lines were used to determine the in vivo flow rates from clearances calculated after injecting the Rickham reservoirs of the patients. The unique clearance characteristics of the individual shunt systems available requires that calibration curves be derived for an entire system identical to one implanted in the patient being evaluated, rather than just the injected chamber. Excellent correlation between flow rates and the clinical findings supports the reliability of this method of quantification of CSF shunt flow, and the results are fully accepted by neurosurgeons.

  13. Active shunt capacitance cancelling oscillator circuit

    DOEpatents

    Wessendorf, Kurt O.

    2003-09-23

    An oscillator circuit is disclosed which can be used to produce oscillation using a piezoelectric crystal, with a frequency of oscillation being largely independent of any shunt capacitance associated with the crystal (i.e. due to electrodes on the surfaces of the crystal and due to packaging and wiring for the crystal). The oscillator circuit is based on a tuned gain stage which operates the crystal at a frequency, f, near a series resonance frequency, f.sub.S. The oscillator circuit further includes a compensation circuit that supplies all the ac current flow through the shunt resistance associated with the crystal so that this ac current need not be supplied by the tuned gain stage. The compensation circuit uses a current mirror to provide the ac current flow based on the current flow through a reference capacitor that is equivalent to the shunt capacitance associated with the crystal. The oscillator circuit has applications for driving piezoelectric crystals for sensing of viscous, fluid or solid media by detecting a change in the frequency of oscillation of the crystal and a resonator loss which occur from contact of an exposed surface of the crystal by the viscous, fluid or solid media.

  14. Ventriculoperitoneal shunt dysfunction and constipation: a chart review.

    PubMed

    Bragg, C L; Edwards-Beckett, J; Eckle, N; Principe, K; Terry, D

    1994-10-01

    Children treated for hydrocephalus frequently experience chronic constipation. A retrospective chart review was conducted to determine if there is a population of children with ventriculoperitoneal (VP) shunt dysfunction in whom constipation might be a factor in the shunt dysfunction. Of 51 cases reviewed, 19 had documented constipation, such as no bowel movement for 2 or more days, small hard ball-like stools or fullness of the colon noted on physical examination or abdominal radiographs. In 6 cases, a bowel cleansing was performed and signs and symptoms of shunt dysfunction resolved without shunt revision. This review suggests that constipation may affect the fluid or pressure dynamics of the VP shunt and contribute to shunt dysfunction.

  15. CSF shunt complications: what the abdominal imager needs to know.

    PubMed

    Rinker, Eric K; Williams, Todd R; Myers, Daniel T

    2015-08-01

    Cerebrospinal fluid (CSF) shunting has been a mainstay in the treatment of hydrocephalus for many decades. With a reported 33,000 shunt placement procedures performed in the US annually, and a lifetime revision rate approaching 50%, abdominal radiologists must be familiar with the typical imaging appearance of an array of shunt complications. Complications related to the peritoneal portion of the shunt have been reported in up to 25% of patients. We present a comprehensive pictorial essay including computed tomography, conventional radiography, ultrasound, and nuclear medicine examples illustrating abdominal complications related to CSF shunting and a review of the current literature. The purpose of this pictorial essay is to provide multimodality imaging examples of CSF shunt complications and familiarize the abdominal imager with the spectrum of findings.

  16. Shunt current loss of the vanadium redox flow battery

    NASA Astrophysics Data System (ADS)

    Xing, Feng; Zhang, Huamin; Ma, Xiangkun

    The shunt current loss is one of main factors to affect the performance of the vanadium redox flow battery, which will shorten the cycle life and decrease the energy transfer efficiency. In this paper, a stack-level model based on the circuit analog method is proposed to research the shunt current loss of the vanadium redox flow battery, in which the SOC (state of charge) of electrolyte is introduced. The distribution of shunt current is described in detail. The sensitive analysis of shunt current is reported. The shunt current loss in charge/discharge cycle is predicted with the given experimental data. The effect of charge/discharge pattern on the shunt current loss is studied. The result shows that the reduction of the number of single cells in series, the decrease of the resistances of manifold and channel and the increase of the power of single cell will be the further development for the VRFB stack.

  17. Factors affecting ventriculoperitoneal shunt survival in adult patients

    PubMed Central

    Khan, Farid; Rehman, Abdul; Shamim, Muhammad S.; Bari, Muhammad E.

    2015-01-01

    Background: Ventriculoperitoneal (VP) shunt insertion remains the mainstay of treatment for hydrocephalus despite a high rate of complications. The predictors of shunt malfunction have been studied mostly in pediatric patients. In this study, we report our 11-year experience with VP shunts in adult patients with hydrocephalus. We also assess the various factors affecting shunt survival in a developing country setting. Methods: A retrospective chart analysis was conducted for all adult patients who had undergone shunt placement between the years 2001 and 2011. Kaplan–Meier curves were used to determine the duration from shunt placement to first malfunction and log-rank (Cox–Mantel) tests were used to determine the factors affecting shunt survival. Results: A total of 227 patients aged 18–85 years (mean: 45.8 years) were included in the study. The top four etiologies of hydrocephalus included post-cranial surgery (23.3%), brain tumor or cyst (22.9%), normal pressure hydrocephalus (15%), and intracranial hemorrhage (13.7%). The overall incidence of shunt malfunction was 15.4% with the median time to first shunt failure being 120 days. Etiology of hydrocephalus (P = 0.030) had a significant association with the development of shunt malfunction. Early shunt failure was associated with age (P < 0.001), duration of hospital stay (P < 0.001), Glasgow Coma Scale (GCS) score less than 13 (P = 0.010), excision of brain tumors (P = 0.008), and placement of extra-ventricular drains (P = 0.033). Conclusions: Patients with increased age, prolonged hospital stay, GCS score of less than 13, extra-ventricular drains in situ, or excision of brain tumors were more likely to experience early shunt malfunction. PMID:25722930

  18. Diagnostic imaging of ventriculoperitoneal shunt malfunctions and complications.

    PubMed

    Goeser, C D; McLeary, M S; Young, L W

    1998-01-01

    Most pediatric patients with hydrocephalus are treated with ventriculoperitoneal (VP) shunt placement. However, shunt malfunction is common and is usually caused by mechanical failure. Shunt obstructions may be confirmed with radioisotope examination or with fluoroscopically guided injection of iodinated contrast material into the shunt reservoir. Disconnections or breaks are more readily detected at radiography in cases in which barium-impregnated shunt tubing was used. Migration and leakage may also occur. Cerebrospinal pseudocysts may be demonstrated with plain radiography and further evaluated with computed tomography (CT) and sonography. In increasing hydrocephalus, plain radiography may reveal sutural diastasis and increased cranial cavity size, and CT can be used to evaluate ventricle size. In cases of enlarging intracranial cysts, injection of iodinated contrast material followed by CT can help document a connection between the cyst and the ventricles. Ventriculitis and meningitis can be visualized at CT and magnetic resonance imaging as enhancement of the ventricular ependymal lining or cerebral cortical sulci. Other complications associated with VP shunts include surgery-related complications, shunt overdrainage and slit-ventricle syndrome, neoplastic metastasis, pleural effusion, and complications related to shunt variants. Imaging analysis is an essential adjunct to the clinical evaluation of patients with suspected VP shunt malfunctions or complications. Radiologists should be familiar with these potential problems and the diagnostic utility of various imaging modalities.

  19. Referred shoulder pain from ventriculoperitoneal shunts. Report of three cases.

    PubMed

    Tubbs, R Shane; Wellons, John C; Blount, Jeffrey P; Grabb, Paul A; Oakes, W Jerry

    2005-03-01

    The authors report on three pediatric patients with ventriculoperitoneal (VP) shunts who presented with chronic right shoulder pain. Imaging revealed that the distal peritoneal catheter was positioned between the right hemidiaphragm and liver. Following surgical repositioning of the distal tubing, all patients experienced resolution of their shoulder pain, which has not recurred. Although seemingly rare, referred shoulder pain from a VP shunt should be added to the list of complications seen with this method of cerebrospinal fluid diversion. The clinician who cares for patients with VP shunts may wish to evaluate cases of shoulder pain without obvious neural or musculoskeletal cause by performing imaging of the distal shunt tubing.

  20. Ventriculoperitoneal shunt malfunction caused by proximal catheter fat obstruction.

    PubMed

    Mizrahi, Cezar José; Spektor, Sergey; Margolin, Emil; Shoshan, Yigal; Ben-David, Eliel; Cohen, José E; Moscovici, Samuel

    2016-08-01

    Ventriculoperitoneal (VP) shunt placement is the mainstay of treatment for hydrocephalus, yet shunts remain vulnerable to a variety of complications. Although fat droplet migration into the subarachnoid space and cerebrospinal fluid pathways following craniotomy has been observed, a VP shunt obstruction with fat droplets has never been reported to our knowledge. We present the first reported case of VP shunt catheter obstruction by migratory fat droplets in a 55-year-old woman who underwent suboccipital craniotomy for removal of a metastatic tumor of the left medullocerebellar region, without fat harvesting. A VP shunt was inserted 1month later due to communicating hydrocephalus. The patient presented with gait disturbance, intermittent confusion, and pseudomeningocele 21days after shunt insertion. MRI revealed retrograde fat deposition in the ventricular system and VP shunt catheter, apparently following migration of fat droplets from the fatty soft tissue of the craniotomy site. Spinal tap revealed signs of aseptic meningitis. Steroid treatment for aseptic "lipoid" meningitis provided symptom relief. MRI 2months later revealed partial fat resorption and resolution of the pseudomeningocele. VP shunt malfunction caused by fat obstruction of the ventricular catheter should be acknowledged as a possible complication in VP shunts after craniotomy, even in the absence of fat harvesting.

  1. Superconducting fault current-limiter with variable shunt impedance

    SciTech Connect

    Llambes, Juan Carlos H; Xiong, Xuming

    2013-11-19

    A superconducting fault current-limiter is provided, including a superconducting element configured to resistively or inductively limit a fault current, and one or more variable-impedance shunts electrically coupled in parallel with the superconducting element. The variable-impedance shunt(s) is configured to present a first impedance during a superconducting state of the superconducting element and a second impedance during a normal resistive state of the superconducting element. The superconducting element transitions from the superconducting state to the normal resistive state responsive to the fault current, and responsive thereto, the variable-impedance shunt(s) transitions from the first to the second impedance. The second impedance of the variable-impedance shunt(s) is a lower impedance than the first impedance, which facilitates current flow through the variable-impedance shunt(s) during a recovery transition of the superconducting element from the normal resistive state to the superconducting state, and thus, facilitates recovery of the superconducting element under load.

  2. Semi-shunt field emission in electronic devices

    SciTech Connect

    Karpov, V. G.; Shvydka, Diana

    2014-08-04

    We introduce a concept of semi-shunts representing needle shaped metallic protrusions shorter than the distance between a device electrodes. Due to the lightening rod type of field enhancement, they induce strong electron emission. We consider the corresponding signature effects in photovoltaic applications; they are: low open circuit voltages and exponentially strong random device leakiness. Comparing the proposed theory with our data for CdTe based solar cells, we conclude that stress can stimulate semi-shunts' growth making them shunting failure precursors. In the meantime, controllable semi-shunts can play a positive role mitigating the back field effects in photovoltaics.

  3. Osler-Weber-Rendu disease presenting as recurrent portosystemic encephalopathy in a 75-year-old female patient.

    PubMed

    Ha, Junghoon; Son, Byoung Kwan; Ahn, Sang Bong; Jo, Young Kwan; Kim, Seong Hwan; Jo, Yun Ju; Park, Young Sook; Jung, Yoon Young

    2015-01-01

    Osler-Weber-Rendu disease is a rare autosomal dominant disorder of fibrovascular tissues, characterized by a classic triad of mucocutaneous telangiectasias, recurrent hemorrhages, and a familial occurrence. Portosystemic encephalopathy in a patient with Osler-Weber-Rendu disease is rare, but we experienced a case presenting with recurrent portosystemic encephalopathy in Osler-Weber-Rendu disease. We report on a case of a 75-year-old female presenting with an altered mentality. Initial studies including brain imaging study did not reveal any specific cause for her mental status. She was diagnosed with the rare disease after a series of tests and received conservative treatment. Her neurological status recovered fully without complication after conservative treatment and she was discharged after 18 hospital days. This case demonstrated an extremely rare case of Osler-Weber-Rendu disease presenting as portosystemic encephalopathy treated successfully with conservative treatment. For patients who have shown hepatic encephalopathy without a definite cause, we recommend evaluation for the possibility of Osler-Weber-Rendu disease. Conservative treatment based on treatment of advanced liver cirrhosis could be an alternative solution. PMID:25603856

  4. A laparoscopic technique for retrieval and prevention of migration of ventriculoperitoneal shunt tubing.

    PubMed

    Klee, Vanessa M; Craft, Randall O; Zimmerman, Richard S; Harold, Kristi L

    2009-01-01

    A 31-year-old female with a history of pseudotumor cerebri presented with headache and abdominal discomfort after placement of a ventriculoperitoneal (VP) shunt. The VP shunt was placed after prior failure and revision of a lumbar peritoneal shunt. Computed tomography demonstrated shunt migration into the subcutaneous tissue. Laparoscopy was used to reposition the VP shunt, directing the shunt toward the pelvis. The patient presented for further evaluation one month later, at which point the shunt was shown to have migrated into the subcutaneous tissue once again. Laparoscopy was again used to reposition the shunt and affix it to the abdominal wall by using polytetrafluoroethylene (PTFE) mesh.

  5. Paediatric ventriculoperitoneal shunt infection caused by Actinomyces neuii.

    PubMed

    Anderson, Ian A; Jarral, Fazain; Sethi, Kavita; Chumas, Paul D

    2014-05-23

    We present the first reported case of ventriculoperitoneal shunt infection secondary to Actinomyces neuii in a paediatric patient. Our patient was managed with temporary shunt removal, intrathecal antibiotics and a prolonged course of intravenous and then oral antibiotics. She went on to make a complete recovery. Subsequent cerebrospinal fluid analysis at 5 months post-treatment demonstrated no evidence of residual infection.

  6. Spontaneous knot; a rare cause of ventriculoperitoneal shunt blockage.

    PubMed

    Mohammed, Wail; Wiig, Ulrikke; Caird, John

    2011-02-01

    A 14-year old X linked congenital hydrocephalus presented with unexplained headaches and vomiting. He had external ventricular drain and intracranial pressure monitoring (ICP). Subsequently, he underwent exploration and removal of previously inserted ventriculoperitoneal (VP) shunts. On retrieval of peritoneal catheters a double knot was noted between his two distal catheters. This case illustrates a rare cause of ventriculoperitoneal shunt malfunction.

  7. [Temporary vascular shunt technique for resource scarce environments].

    PubMed

    Ouattara, N; Mlynski, A; Pierret, C

    2011-10-01

    The purpose of this report is to describe a simple and reproducible technique for temporary vascular shunting. This technique is appropriate only for exceptional situations involving scant resource availability. It is not intended to replace conventional vascular shunting techniques. PMID:22235609

  8. Internal carotid artery rupture caused by carotid shunt insertion

    PubMed Central

    Illuminati, Giulio; Caliò, Francesco G.; Pizzardi, Giulia; Vietri, Francesco

    2015-01-01

    Introduction Shunting is a well-accepted method of maintaining cerebral perfusion during carotid endarterectomy (CEA). Nonetheless, shunt insertion may lead to complications including arterial dissection, embolization, and thrombosis. We present a complication of shunt insertion consisting of arterial wall rupture, not reported previously. Presentation of case A 78-year-old woman underwent CEA combined with coronary artery bypass grafting (CABG). At the time of shunt insertion an arterial rupture at the distal tip of the shunt was detected and was repaired via a small saphenous vein patch. Eversion CEA and subsequent CABG completed the procedure whose postoperative course was uneventful. Discussion Shunting during combined CEA-CABG may be advisable to assure cerebral protection from possible hypoperfusion due to potential hemodynamic instability of patients with severe coronary artery disease. Awareness and prompt management of possible shunt-related complications, including the newly reported one, may contribute to limiting their harmful effect. Conclusion Arterial wall rupture is a possible, previously not reported, shunt-related complication to be aware of when performing CEA. PMID:26255001

  9. 21 CFR 882.4545 - Shunt system implantation instrument.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Shunt system implantation instrument. 882.4545 Section 882.4545 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Surgical Devices § 882.4545 Shunt system implantation instrument. (a) Identification....

  10. 49 CFR 236.724 - Circuit, shunt fouling.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Circuit, shunt fouling. 236.724 Section 236.724... Circuit, shunt fouling. The track circuit in the fouling section of a turnout, connected in multiple with the track circuit in the main track....

  11. 49 CFR 236.724 - Circuit, shunt fouling.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Circuit, shunt fouling. 236.724 Section 236.724... Circuit, shunt fouling. The track circuit in the fouling section of a turnout, connected in multiple with the track circuit in the main track....

  12. 49 CFR 236.724 - Circuit, shunt fouling.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Circuit, shunt fouling. 236.724 Section 236.724... Circuit, shunt fouling. The track circuit in the fouling section of a turnout, connected in multiple with the track circuit in the main track....

  13. 21 CFR 874.3850 - Endolymphatic shunt tube with valve.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3850 Endolymphatic shunt tube with valve. (a) Identification. An endolymphatic shunt tube with valve is a device that consists... device is the FDA guidance document “Class II Special Controls Guidance Document: Endolymphatic...

  14. 21 CFR 874.3850 - Endolymphatic shunt tube with valve.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3850 Endolymphatic shunt tube with valve. (a) Identification. An endolymphatic shunt tube with valve is a device that consists... device is the FDA guidance document “Class II Special Controls Guidance Document: Endolymphatic...

  15. 21 CFR 876.5955 - Peritoneo-venous shunt.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Peritoneo-venous shunt. 876.5955 Section 876.5955 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5955 Peritoneo-venous shunt....

  16. 21 CFR 876.5955 - Peritoneo-venous shunt.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Peritoneo-venous shunt. 876.5955 Section 876.5955 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5955 Peritoneo-venous shunt....

  17. 21 CFR 876.5955 - Peritoneo-venous shunt.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Peritoneo-venous shunt. 876.5955 Section 876.5955 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5955 Peritoneo-venous shunt....

  18. 21 CFR 876.5955 - Peritoneo-venous shunt.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Peritoneo-venous shunt. 876.5955 Section 876.5955 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5955 Peritoneo-venous shunt....

  19. 49 CFR 236.724 - Circuit, shunt fouling.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Circuit, shunt fouling. 236.724 Section 236.724... Circuit, shunt fouling. The track circuit in the fouling section of a turnout, connected in multiple with the track circuit in the main track....

  20. 21 CFR 874.3850 - Endolymphatic shunt tube with valve.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Endolymphatic shunt tube with valve. 874.3850... tube with valve. (a) Identification. An endolymphatic shunt tube with valve is a device that consists of a pressure-limiting valve associated with a tube intended to be implanted in the inner ear...

  1. 21 CFR 874.3850 - Endolymphatic shunt tube with valve.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Endolymphatic shunt tube with valve. 874.3850... tube with valve. (a) Identification. An endolymphatic shunt tube with valve is a device that consists of a pressure-limiting valve associated with a tube intended to be implanted in the inner ear...

  2. 21 CFR 874.3850 - Endolymphatic shunt tube with valve.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Endolymphatic shunt tube with valve. 874.3850... tube with valve. (a) Identification. An endolymphatic shunt tube with valve is a device that consists of a pressure-limiting valve associated with a tube intended to be implanted in the inner ear...

  3. Shunt attachment and method for interfacing current collection systems

    DOEpatents

    Denney, Paul E.; Iyer, Natraj C.; Hannan, III, William F.

    1992-01-01

    A composite brush to shunt attachment wherein a volatile component of a composite but mostly metallic brush, used for current collection purposes, does not upon welding or brazing, adversely affect the formation of the interfacial bond with a conductive shunt which carries the current from the zone of the brush. The brush to shunt attachment for a brush material of copper-graphite composite and a shunt of copper, or substituting silver for copper as an alternative, is made through a hot isostatic pressing (HIP). The HIP process includes applying high pressure and temperature simultaneously at the brush to shunt interface, after it has been isolated or canned in a metal casing in which the air adjacent to the interface has been evacuated and the interfacial area has been sealed before the application of pressure and temperature.

  4. Shunt attachment and method for interfacing current collection systems

    DOEpatents

    Denney, P.E.; Iyer, N.C.; Hannan, W.F. III.

    1992-12-08

    A composite brush to shunt attachment wherein a volatile component of a composite but mostly metallic brush, used for current collection purposes, does not upon welding or brazing, adversely affect the formation of the interfacial bond with a conductive shunt which carries the current from the zone of the brush. The brush to shunt attachment for a brush material of copper-graphite composite and a shunt of copper, or substituting silver for copper as an alternative, is made through a hot isostatic pressing (HIP). The HIP process includes applying high pressure and temperature simultaneously at the brush to shunt interface, after it has been isolated or canned in a metal casing in which the air adjacent to the interface has been evacuated and the interfacial area has been sealed before the application of pressure and temperature. 6 figs.

  5. The role of lumboperitoneal shunts in the treatment of syringomyelia.

    PubMed

    Oluigbo, Chima O; Thacker, Karen; Flint, Graham

    2010-07-01

    OBJECT The role of thecoperitoneal shunts in the management of syringomyelia is not well defined. In this study, the authors analyze the outcome of lumboperitoneal shunt procedures carried out to treat syringomyelia in their institution. METHODS The authors retrospectively reviewed the medical records of 19 patients who underwent lumboperitoneal shunt procedures for syringomyelia. RESULTS The mean follow-up duration was 25 months (range 3-51 months). Of 16 cases followed up, only 5 patients reported clinical improvement in their preoperative symptoms, but of these, 2 had clear radiological evidence of improvement. Three of 6 patients with syringomyelia due to spinal arachnoiditis improved. CONCLUSIONS Lumboperitoneal shunts may lead to useful improvement in the symptoms of a patient with syringomyelia while avoiding the risk of neurological deterioration inherent in myelotomies required for syrinx shunting procedures.

  6. Biosynthetic route towards saxitoxin and shunt pathway.

    PubMed

    Tsuchiya, Shigeki; Cho, Yuko; Konoki, Keiichi; Nagasawa, Kazuo; Oshima, Yasukatsu; Yotsu-Yamashita, Mari

    2016-02-04

    Saxitoxin, the most potent voltage-gated sodium channel blocker, is one of the paralytic shellfish toxins (PSTs) produced by cyanobacteria and dinoflagellates. Recently, putative biosynthetic genes of PSTs were reported in these microorganisms. We previously synthesized genetically predicted biosynthetic intermediates, Int-A' and Int-C'2, and also Cyclic-C' which was not predicted based on gene, and identified them all in the toxin-producing cyanobacterium Anabaena circinalis (TA04) and the dinoflagellate Alexandrium tamarense (Axat-2). This study examined the incorporation of (15)N-labeled intermediates into PSTs (C1 and C2) in A. circinalis (TA04). Conversions from Int-A' to Int-C'2, from Int-C'2 to Cyclic-C', and from Int-A' and Int-C'2 to C1 and C2 were indicated using high resolution-LC/MS. However, Cyclic-C' was not converted to C1 and C2 and was detected primarily in the extracellular medium. These results suggest that Int-A' and Int-C'2 are genuine precursors of PSTs, but Int-C'2 converts partially to Cyclic-C' which is a shunt product excreted to outside the cells. This paper provides the first direct demonstration of the biosynthetic route towards saxitoxin and a shunt pathway.

  7. Ventriculoperitoneal shunt infection with Listeria innocua.

    PubMed

    Karli, Arzu; Sensoy, Gulnar; Unal, Nevzat; Yanik, Keramettin; Cigdem, Halit; Belet, Nursen; Sofuoglu, Ayse

    2014-08-01

    Listeria species may cause life-threatening events including meningitis and invasive infection in newborns, pregnant women, older and immunodeficient people. The most common Listeria species that causes infection is L. monocytogenes. It is known that Listeria innocua has no pathogenicity. A 9-month-old baby had ventriculoperitoneal shunt and was treated with adrenocorticotropic hormone because of infantile spasms. He was brought to hospital with fever and vomiting. Upon physical examination, the patient seemed uncomfortable and had a temperature of 38.6°C. Laboratory results were as follows: hemoglobin, 6.7 g/dL; leukocyte count, 5420/mm(3) ; platelet count, 169,000/mm(3) ; and C-reactive protein, 100 mg/L (normal <5 mg/L). On analysis of cerebrospinal fluid (CSF), leukocyte count was 480/mm(3) , protein was 46 mg/dL and CSF glucose was 35 mg/dL. L. innocua was isolated in CSF culture. We describe this unusual case of ventriculoperitoneal shunt infection with L. innocua.

  8. Flexural waves focusing through shunted piezoelectric patches

    NASA Astrophysics Data System (ADS)

    Yi, K.; Collet, M.; Ichchou, M.; Li, L.

    2016-07-01

    In this paper, we designed and analyzed a piezo-lens to focus flexural waves in thin plates. The piezo-lens is comprised of a host plate and piezoelectric arrays bonded on the surfaces of the plate. The piezoelectric patches are shunted with negative capacitance circuits. The effective refractive indexes inside the piezo-lens are designed to fit a hyperbolic secant distribution by tuning the negative capacitance values. A homogenized model of a piezo-mechanical system is adopted in the designing process of the piezo-lens. The wave focusing effect is studied by the finite element method. Numerical results show that the piezo-lens can focus flexural waves by bending their trajectories, and is effective in a large frequency band. The piezo-lens has the ability to focus flexural waves at different locations by tuning the shunting negative capacitance values. The piezo-lens is shown to be effective for flexural waves generated by different types of sources.

  9. Parylene MEMS patency sensor for assessment of hydrocephalus shunt obstruction.

    PubMed

    Kim, Brian J; Jin, Willa; Baldwin, Alexander; Yu, Lawrence; Christian, Eisha; Krieger, Mark D; McComb, J Gordon; Meng, Ellis

    2016-10-01

    Neurosurgical ventricular shunts inserted to treat hydrocephalus experience a cumulative failure rate of 80 % over 12 years; obstruction is responsible for most failures with a majority occurring at the proximal catheter. Current diagnosis of shunt malfunction is imprecise and involves neuroimaging studies and shunt tapping, an invasive measurement of intracranial pressure and shunt patency. These patients often present emergently and a delay in care has dire consequences. A microelectromechanical systems (MEMS) patency sensor was developed to enable direct and quantitative tracking of shunt patency in order to detect proximal shunt occlusion prior to the development of clinical symptoms thereby avoiding delays in treatment. The sensor was fabricated on a flexible polymer substrate to eventually allow integration into a shunt. In this study, the sensor was packaged for use with external ventricular drainage systems for clinical validation. Insights into the transduction mechanism of the sensor were obtained. The impact of electrode size, clinically relevant temperatures and flows, and hydrogen peroxide (H2O2) plasma sterilization on sensor function were evaluated. Sensor performance in the presence of static and dynamic obstruction was demonstrated using 3 different models of obstruction. Electrode size was found to have a minimal effect on sensor performance and increased temperature and flow resulted in a slight decrease in the baseline impedance due to an increase in ionic mobility. However, sensor response did not vary within clinically relevant temperature and flow ranges. H2O2 plasma sterilization also had no effect on sensor performance. This low power and simple format sensor was developed with the intention of future integration into shunts for wireless monitoring of shunt state and more importantly, a more accurate and timely diagnosis of shunt failure.

  10. Parylene MEMS patency sensor for assessment of hydrocephalus shunt obstruction.

    PubMed

    Kim, Brian J; Jin, Willa; Baldwin, Alexander; Yu, Lawrence; Christian, Eisha; Krieger, Mark D; McComb, J Gordon; Meng, Ellis

    2016-10-01

    Neurosurgical ventricular shunts inserted to treat hydrocephalus experience a cumulative failure rate of 80 % over 12 years; obstruction is responsible for most failures with a majority occurring at the proximal catheter. Current diagnosis of shunt malfunction is imprecise and involves neuroimaging studies and shunt tapping, an invasive measurement of intracranial pressure and shunt patency. These patients often present emergently and a delay in care has dire consequences. A microelectromechanical systems (MEMS) patency sensor was developed to enable direct and quantitative tracking of shunt patency in order to detect proximal shunt occlusion prior to the development of clinical symptoms thereby avoiding delays in treatment. The sensor was fabricated on a flexible polymer substrate to eventually allow integration into a shunt. In this study, the sensor was packaged for use with external ventricular drainage systems for clinical validation. Insights into the transduction mechanism of the sensor were obtained. The impact of electrode size, clinically relevant temperatures and flows, and hydrogen peroxide (H2O2) plasma sterilization on sensor function were evaluated. Sensor performance in the presence of static and dynamic obstruction was demonstrated using 3 different models of obstruction. Electrode size was found to have a minimal effect on sensor performance and increased temperature and flow resulted in a slight decrease in the baseline impedance due to an increase in ionic mobility. However, sensor response did not vary within clinically relevant temperature and flow ranges. H2O2 plasma sterilization also had no effect on sensor performance. This low power and simple format sensor was developed with the intention of future integration into shunts for wireless monitoring of shunt state and more importantly, a more accurate and timely diagnosis of shunt failure. PMID:27589973

  11. Pathogenesis of Hepatic Encephalopathy

    PubMed Central

    Ciećko-Michalska, Irena; Szczepanek, Małgorzata; Słowik, Agnieszka; Mach, Tomasz

    2012-01-01

    Hepatic encephalopathy can be a serious complication of acute liver failure and chronic liver diseases, predominantly liver cirrhosis. Hyperammonemia plays the most important role in the pathogenesis of hepatic encephalopathy. The brain-blood barrier disturbances, changes in neurotransmission, neuroinflammation, oxidative stress, GABA-ergic or benzodiazepine pathway abnormalities, manganese neurotoxicity, brain energetic disturbances, and brain blood flow abnormalities are considered to be involved in the development of hepatic encephalopathy. The influence of small intestine bacterial overgrowth (SIBO) on the induction of minimal hepatic encephalopathy is recently emphasized. The aim of this paper is to present the current views on the pathogenesis of hepatic encephalopathy. PMID:23316223

  12. Vascular collateralization along ventriculoperitoneal shunt catheters in moyamoya disease.

    PubMed

    Singla, Amit; Lin, Ning; Ho, Allen L; Scott, R Michael; Smith, Edward R

    2013-06-01

    Surgically created openings such as bur holes can serve as avenues for the development of collateral blood supply to the brain in patients with moyamoya disease. When such collateralization occurs through preexisting shunt catheter sites, the potential exists for perioperative stroke if these vessels are damaged during revision of a ventricular catheter for shunt malfunction. In this paper the authors report on a series of patients with a history of ventriculoperitoneal (VP) shunts who later developed moyamoya disease and were found to have spontaneous transdural collateral vessels at ventricular catheter sites readily visualized on diagnostic angiography. A consecutive surgical series of 412 patients with moyamoya disease treated at Boston Children's Hospital from 1990 to 2010 were reviewed to identify patients with concomitant moyamoya and a VP shunt. The clinical records and angiograms of these patients were reviewed to determine the extent of bur hole collaterals through the shunt site. Three patients were identified who had VP shunts placed for hydrocephalus and subsequently developed moyamoya disease. All 3 patients demonstrated spontaneous transdural collaterals at the ventricular catheter bur hole, as confirmed by angiography during the workup for moyamoya disease. No patients required subsequent revision of their ventricular catheters following the diagnosis of moyamoya. All patients have remained stroke free and clinically stable following pial synangiosis. Although the association of moyamoya and shunted hydrocephalus is rare, it may present a significant potential problem for the neurosurgeon treating a shunt malfunction in this patient population, because shunt bur holes may become entry sites for the ingrowth of significant cortical transdural collateral blood supply to the underlying brain. Shunt revision might therefore be associated with an increased risk of postoperative stroke or operative-site hemorrhage in this population if this

  13. Hepatitis E Pathogenesis

    PubMed Central

    Lhomme, Sébastien; Marion, Olivier; Abravanel, Florence; Chapuy-Regaud, Sabine; Kamar, Nassim; Izopet, Jacques

    2016-01-01

    Although most hepatitis E virus (HEV) infections are asymptomatic, some can be severe, causing fulminant hepatitis and extra-hepatic manifestations, including neurological and kidney injuries. Chronic HEV infections may also occur in immunocompromised patients. This review describes how our understanding of the pathogenesis of HEV infection has progressed in recent years. PMID:27527210

  14. Hepatitis E Pathogenesis.

    PubMed

    Lhomme, Sébastien; Marion, Olivier; Abravanel, Florence; Chapuy-Regaud, Sabine; Kamar, Nassim; Izopet, Jacques

    2016-01-01

    Although most hepatitis E virus (HEV) infections are asymptomatic, some can be severe, causing fulminant hepatitis and extra-hepatic manifestations, including neurological and kidney injuries. Chronic HEV infections may also occur in immunocompromised patients. This review describes how our understanding of the pathogenesis of HEV infection has progressed in recent years. PMID:27527210

  15. The hydrokinetic parameters of shunts for hydrocephalus might be inadequate.

    PubMed

    Sotelo, Julio

    2012-01-01

    Long-term treatment of hydrocephalus continues to be dismal. Shunting is the neurosurgical procedure more frequently associated with complications, which are mostly related with dysfunctions of the shunting device, rather than to mishaps of the rather simple surgical procedure. Overdrainage and underdrainage are the most common dysfunctions; of them, overdrainage is a conspicuous companion of most devices. Even when literally hundreds of different models have been proposed, developed, and tested, overdrainage has plagued all shunts for the last 60 years. Several investigations have demonstrated that changes in the posture of the subject induce unavoidable and drastic differences of intraventricular hydrokinetic pressure and cerebrospinal fluid (CSF) drainage through the shunt. Of all the parameters that participate in the pathophysiology of hydrocephalus, the only invariable one is cerebrospinal fluid production at a constant rate of approximately 0.35 ml/min. However, this feature has not been considered in the design of currently available shunts. Our experimental and clinical studies have shown that a simple shunt, whose drainage capacity complies with this unique parameter, would prevent most complications of shunting for hydrocephalus.

  16. Exploration of nonlinearly shunted piezoelectrics as vibration absorbers

    NASA Astrophysics Data System (ADS)

    Zhou, B.; Zang, C.; Wang, X.

    2016-09-01

    Practical realization of a nonlinearly shunted piezoelectric vibration absorber is numerically explored in this research. It is widely known that the linear resonant piezoelectric shunting strategy, acting as a tuned mass damper, is limited by the massive inductance required in low-frequency cases and sensitivity to drifts in structural frequencies. In order to overcome this limitation, a nonlinear piezoelectric shunting strategy is proposed based on the nonlinear energy sink theory. The essential idea is to passively absorb vibrational energy from the host structure through the intentional use of nonlinearity in piezoelectric shunting. The nonlinearly shunted piezoelectrics are supposed to work over a broad frequency band with a smaller inductance requirement compared with the linear resonant shunting. The nonlinearly shunted piezoelectric vibration absorber is built and applied in a cantilevered beam. Major challenges coming from the nonlinear tuning design for an effective vibration absorber exempted from high isolated response curves will be covered in this research. This numerical study is supposed to pave the way for experimental investigations that are currently in process.

  17. Shunt malfunction presenting with symptomatic syringomyelia: Demonstrated on contrast ventriculogram

    PubMed Central

    Aniruddha, T. J; Pruthi, Nupur

    2014-01-01

    Ventriculoperitoneal (VP) shunt malfunction commonly presents as raised intracranial pressure. Rarely, when the central canal of the spinal cord communicates with the 4th ventricle, shunt malfunction can present as an expanding syrinx. The diagnosis is often delayed, resulting in severe morbidity. Some of these patients undergo repeated syrinx surgeries without much benefits. We report a case of chronic tuberculous meningitis with shunt malfunction presenting as an expanding spinal canal syrinx and quadriparesis. Fourth ventricular communication with syrinx was demonstrated with the help of a contrast ventriculogram. After shunt revision, syrinx resolved completely and the patient made significant improvement in his neurological deficits. The present case illustrates that a historical and rarely used investigation like contrast ventriculogram aids in the diagnosis and management even in the current neurosurgical practice. All patients with late onset syrinx and a previous VP shunt need to be investigated for shunt malfunction before considering syrinx surgery. A simple shunt revision resolves the syrinx in such conditions and avoids more complex procedures like Foramen magnum decompression. Relevant literature has been reviewed; pathophysiology and management options have been discussed. PMID:25250067

  18. The hydrokinetic parameters of shunts for hydrocephalus might be inadequate.

    PubMed

    Sotelo, Julio

    2012-01-01

    Long-term treatment of hydrocephalus continues to be dismal. Shunting is the neurosurgical procedure more frequently associated with complications, which are mostly related with dysfunctions of the shunting device, rather than to mishaps of the rather simple surgical procedure. Overdrainage and underdrainage are the most common dysfunctions; of them, overdrainage is a conspicuous companion of most devices. Even when literally hundreds of different models have been proposed, developed, and tested, overdrainage has plagued all shunts for the last 60 years. Several investigations have demonstrated that changes in the posture of the subject induce unavoidable and drastic differences of intraventricular hydrokinetic pressure and cerebrospinal fluid (CSF) drainage through the shunt. Of all the parameters that participate in the pathophysiology of hydrocephalus, the only invariable one is cerebrospinal fluid production at a constant rate of approximately 0.35 ml/min. However, this feature has not been considered in the design of currently available shunts. Our experimental and clinical studies have shown that a simple shunt, whose drainage capacity complies with this unique parameter, would prevent most complications of shunting for hydrocephalus. PMID:22530174

  19. The hydrokinetic parameters of shunts for hydrocephalus might be inadequate

    PubMed Central

    Sotelo, Julio

    2012-01-01

    Long-term treatment of hydrocephalus continues to be dismal. Shunting is the neurosurgical procedure more frequently associated with complications, which are mostly related with dysfunctions of the shunting device, rather than to mishaps of the rather simple surgical procedure. Overdrainage and underdrainage are the most common dysfunctions; of them, overdrainage is a conspicuous companion of most devices. Even when literally hundreds of different models have been proposed, developed, and tested, overdrainage has plagued all shunts for the last 60 years. Several investigations have demonstrated that changes in the posture of the subject induce unavoidable and drastic differences of intraventricular hydrokinetic pressure and cerebrospinal fluid (CSF) drainage through the shunt. Of all the parameters that participate in the pathophysiology of hydrocephalus, the only invariable one is cerebrospinal fluid production at a constant rate of approximately 0.35 ml/min. However, this feature has not been considered in the design of currently available shunts. Our experimental and clinical studies have shown that a simple shunt, whose drainage capacity complies with this unique parameter, would prevent most complications of shunting for hydrocephalus. PMID:22530174

  20. Atrial-caval shunting (ACS) after trauma.

    PubMed

    Kudsk, K A; Sheldon, G F; Lim, R C

    1982-02-01

    Since 1968 the atrial-caval shunt (ACS), along with inflow occlusion at the porta hepatis, has been used at San Francisco General Hospital in 18 trauma patients to control massive hemorrhage from the inferior vena cava, hepatic veins, or liver. Thirteen patients died from irreversible shock. Five patients survived their initial injuries; one of them died 45 days later from the complications of shock and sepsis. No patients survived who sustained blunt trauma and were admitted in cardiac arrest. Only one of ten patients with BP less than 70 mm Hg after resuscitation survived, whereas four of eight with BP greater than 70 mm Hg survived. ACS was used to control caval injuries in seven patients (one survivor), severe hepatic parenchymal fractures in four patients (two survivors), and combined hepatic and caval injuries in seven patients (two survivors). Survivors had an average of 5.75 associated injuries; nonsurvivors had 3.8. No complications of ACS occurred in the surviving patients.

  1. 49 CFR 236.309 - Loss of shunt protection; where required.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Loss of shunt protection; where required. 236.309... Standards § 236.309 Loss of shunt protection; where required. (a) A loss of shunt of 5 seconds or less shall not permit an established route to be changed at an automatic interlocking. (b) A loss of shunt of...

  2. Serum Cytokines in Young Pediatric Patients with Congenital Cardiac Shunts and Altered Pulmonary Hemodynamics

    PubMed Central

    Zorzanelli, Leína; Maeda, Nair Yukie; Clavé, Mariana Meira; Aiello, Vera Demarchi; Rabinovitch, Marlene

    2016-01-01

    Background and Objective. Inflammation is central in the pathogenesis of pulmonary hypertension. We investigated how serum cytokines correlate with clinical features, hemodynamics, and lung histology in young patients with pulmonary hypertension associated with congenital cardiac shunts. Design. Prospective, observational study. Methods and Results. Patients (n = 44) were aged 2.6 to 37.6 months. Group I patients (n = 31) were characterized by pulmonary congestion and higher pulmonary blood flow compared to group II (p = 0.022), with no need for preoperative cardiac catheterization. Group II patients (n = 13) had no congestive features. At catheterization, they had elevated pulmonary vascular resistance (5.7 [4.4–7.4] Wood units·m2, geometric mean with 95% CI). Cytokines were measured by chemiluminescence. Macrophage migration inhibitory factor (MIF) was found to be inversely related to pulmonary blood flow (r = −0.33, p = 0.026) and was higher in group II (high pulmonary vascular resistance) compared to group I (high pulmonary blood flow) (p = 0.017). In contrast, RANTES chemokine (regulated on activation, normal T cell expressed and secreted) was characteristically elevated in Group I (p = 0.022). Interleukin 16 was also negatively related to pulmonary blood flow (rS = −0.33, p = 0.029) and was higher in patients with obstructive vasculopathy at intraoperative lung biopsy (p = 0.021). Conclusion. Cytokines seem to be important and differentially regulated in subpopulations of young patients with cardiac shunts.

  3. Serum Cytokines in Young Pediatric Patients with Congenital Cardiac Shunts and Altered Pulmonary Hemodynamics

    PubMed Central

    Zorzanelli, Leína; Maeda, Nair Yukie; Clavé, Mariana Meira; Aiello, Vera Demarchi; Rabinovitch, Marlene

    2016-01-01

    Background and Objective. Inflammation is central in the pathogenesis of pulmonary hypertension. We investigated how serum cytokines correlate with clinical features, hemodynamics, and lung histology in young patients with pulmonary hypertension associated with congenital cardiac shunts. Design. Prospective, observational study. Methods and Results. Patients (n = 44) were aged 2.6 to 37.6 months. Group I patients (n = 31) were characterized by pulmonary congestion and higher pulmonary blood flow compared to group II (p = 0.022), with no need for preoperative cardiac catheterization. Group II patients (n = 13) had no congestive features. At catheterization, they had elevated pulmonary vascular resistance (5.7 [4.4–7.4] Wood units·m2, geometric mean with 95% CI). Cytokines were measured by chemiluminescence. Macrophage migration inhibitory factor (MIF) was found to be inversely related to pulmonary blood flow (r = −0.33, p = 0.026) and was higher in group II (high pulmonary vascular resistance) compared to group I (high pulmonary blood flow) (p = 0.017). In contrast, RANTES chemokine (regulated on activation, normal T cell expressed and secreted) was characteristically elevated in Group I (p = 0.022). Interleukin 16 was also negatively related to pulmonary blood flow (rS = −0.33, p = 0.029) and was higher in patients with obstructive vasculopathy at intraoperative lung biopsy (p = 0.021). Conclusion. Cytokines seem to be important and differentially regulated in subpopulations of young patients with cardiac shunts. PMID:27656048

  4. Return to the emergency department after ventricular shunt evaluation.

    PubMed

    Sarda, Samir; Simon, Harold K; Hirsh, Daniel A; Wang, Andrew; Shane Tubbs, R; Chern, Joshua J

    2016-04-01

    OBJECT Patients with CSF shunts are medically complex and frequently present to the emergency department (ED) with suspected shunt malfunction. After adequate evaluation in the ED and proper disposition, some patients return to the ED within a short period of time. In this study, the authors examined the reasons for ED revisits within 7 days of the index ED visit to discern possible preventable returns. METHODS There were 3080 index ED visits made by patients with shunted hydrocephalus between 2010 and 2013. Index ED visits preceded by another ED visit or neurosurgical procedure within 60 days were excluded. Index ED visits for reasons unrelated to shunt function and those that led directly to admissions and shunt revision surgeries were also excluded. The remaining 1509 ED visits were eligible for analysis in this study. Final dispositions from the index ED visit included home (1176 cases), admission to the neurosurgery service for observation (134 cases), and admission to other services (199 cases). Subsequent events within 7 days, including ED revisits, hospital admissions, and shunt-related surgery were recorded, and reasons for the ED revisits were categorized based on whether the visit was related to shunt function concerns. Clinical and socioeconomic factors were analyzed for their association with ED revisits by using statistical methods. RESULTS Of the 1176 patients discharged home from the ED after shunt function evaluation, 101 (8.6%) returned to the ED within 7 days. Of the 134 patients admitted to the neurosurgery service for observation only, 8 (6.0%) returned to the ED within 7 days of discharge. Of the 199 patients admitted to hospital services other than neurosurgery, 13 (6.5%) returned to the ED within 7 days of discharge. The reasons for ED revisits vary (total of 122 visits combining the 3 groups), but at least 60% of the revisits were clearly unrelated to shunt function. A younger age, daytime arrival to the ED, and living within the

  5. Delayed intracerebellar hemorrhage secondary to lumboperitoneal shunt insertion

    PubMed Central

    Er, Uygur; Akyol, Çetin; Bavbek, Murad

    2016-01-01

    Aim of this paper is to present and discuss a case of a delayed cerebellar parenchymal hemorrhage developing after L/P shunt placement with a NPH patient. A hypertensive patient admitted to our clinic with a diagnosis of NPH. The patient was placed a pressure adjustable L/P shunt without any surgical complication. He was discharged with an uneventful period. The patient was admitted to the emergency clinic of our hospital with a 1.5 × 1.5 cm diameter hematoma at the left cerebellar hemisphere on 2 days after his discharge. CSF drainage by an L/P shunt can generate intracerebellar hemorrhages especially in hypertensive patients.

  6. [Abdominal pseudocyst as a complication of ventriculoperitoneal shunt].

    PubMed

    Shakir, Shawnim; Hegelund, Sture

    2013-09-16

    The abdominal pseudocyst is an unfrequent complication in patients with ventriculoperitoneal shunts. Although many cases have been reported in children, it is rare in adult patients. However, a 47-year-old man with congenital hydrocephalus who had been treated with ventriculoperitoneal shunt since the age of three months, was admitted to hospital due to abdominal pain. He was eventually diagnosed radiologically as having an abdominal pseudocyst. Despite this complication being rare, especially in adults, it should be highly suspected whenever an abdominal cyst co-occurs with a ventriculoperitoneal shunt.

  7. Ion beam sputter-etched ventricular catheter for hydrocephalus shunt

    NASA Technical Reports Server (NTRS)

    Banks, B. A. (Inventor)

    1983-01-01

    A cerebrospinal fluid shunt in the form of a ventricular catheter for controlling the condition of hydrocephalus by relieving the excessive cerebrospinal fluid pressure is described. A method for fabrication of the catheter and shunting the cerebral fluid from the cerebral ventricles to other areas of the body is also considered. Shunt flow failure occurs if the ventricle collapse due to improper valve function causing overdrainage. The ventricular catheter comprises a multiplicity of inlet microtubules. Each microtubule has both a large openings at its inlet end and a multiplicity of microscopic openings along its lateral surfaces.

  8. Pollutants removal in subsurface infiltration systems by shunt distributing wastewater with/without intermittent aeration under different shunt ratios.

    PubMed

    Pan, Jing; Yuan, Fang; Zhang, Yang; Huang, Linli; Yu, Long; Zheng, Fanping; Cheng, Fan; Zhang, Jiadi

    2016-10-01

    Matrix dissolved oxygen (DO), removal of COD, TP and nitrogen in subsurface infiltration systems (SISs), named SIS A (without intermittent aeration and shunt distributing wastewater), SIS B (with shunt distributing wastewater) and SIS C (with intermittent aeration and shunt distributing wastewater) were investigated. Aerobic conditions were developed in 50cm depth and anoxic or anaerobic conditions were not changed in 80 and 110cm depth by intermittent aeration. Under appropriate shunt ratios, shunt distributing wastewater improved denitrification and had little influence on COD, TP and NH3-N removal. Under the optimal shunt ratio of 1:2 for SIS C, high average removal rates of COD (90.06%), TP (93.17%), NH3-N (88.20%) and TN (85.79%) were obtained, which were higher than those in SIS A (COD: 82.56%, TP: 92.76%, NH3-N: 71.08%, TN: 49.24%) and SIS B (COD: 81.12%, TP: 92.58%, NH3-N: 69.14%, TN: 58.73%) under the optimal shunt ratio of 1:3.

  9. A neonate with a meningomyelocele complicated by Aeromonas caviae ventriculoperitoneal shunt infection.

    PubMed

    den Butter, C P; Mahieu, L M

    2013-01-01

    We report on a newborn girl with a Aeromonas caviae shunt infection and meningitis after insertion of a ventriculoperitoneal shunt and surgical repair of a meningomyelocele in one procedure. This pathogen has never been reported, related to ventriculoperitoneal shunt infections. Beside the need for surgical revision of the shunt because of shunt obstruction and septa formation in the ventricles, the clinical outcome was good with intravenous cefotaxime therapy.

  10. [Pathogenesis of psoriasis].

    PubMed

    Schäkel, K; Schön, M P; Ghoreschi, K

    2016-06-01

    Psoriasis is an inflammatory T cell-mediated autoimmune disease of skin and joints that affects 2-4 % of the adult population and 0.1-1 % of children. Genetic susceptibility, environmental triggering factors, and innate immune processes initiate psoriasis pathogenesis that results in an adaptive autoreactive response. The T cell response is orchestrated by CD 8(+) T cells in the epidermis and by CD 4(+) T cells in the dermis that predominantly produce interleukin-17 (IL‑17). Research of the past 15 years unraveled cellular and molecular mechanisms as well as cytokines like TNF-α or IL‑23 that contribute to psoriatic inflammation. This knowledge has been translated into clinical practice and a number of antipsoriatic small molecules and immunobiologics are now available. Here, we discuss the current principles of psoriasis pathogenesis in the context of modern therapies.

  11. Malignant cause of ventriculoperitoneal shunt 'pseudocyst': a case report.

    PubMed

    Awori, Jonathan; Wu, Chris Y; Maher, Cormac O

    2015-01-01

    Abdominal pseudocysts are an uncommon complication of ventriculoperitoneal (VP) shunts. We present the case of a 4-year-old boy with a history of complicated hydrocephalus managed with a VP shunt due to sequelae of prematurity. The patient presented with abdominal distention, and a pseudocyst was diagnosed. Despite shunt externalization and aspiration, the pseudocyst continued to produce up to 1 liter of serosanguineous fluid per day. After MRI revealed malignant features within the pseudocyst, laparotomy was performed and the pseudocyst was partially excised. Pathology reports suggested sarcoma. The cystic mass grew back aggressively, accompanied by distant metastasis. The patient's condition deteriorated and he died from his disease. To our knowledge, this represents the first report of an abdominal malignancy mimicking a pseudocyst and causing VP shunt failure.

  12. Zero tolerance to shunt infections: can it be achieved?

    PubMed Central

    Choksey, M; Malik, I

    2004-01-01

    Objective: To evaluate the rigid application of a technique of shunt placement aimed at the eradication of postoperative shunt infection in neurosurgical practice. Method: All shunt procedures were performed or closely supervised by the senior author (MSC). The essentials were the use of intravenous peri- and postoperative antimicrobials, rigid adherence to classical aseptic technique, liberal use of topical antiseptic (Betadine®), and avoidance of haematomas. Results: Of 176 operations, 93 were primary procedures; 33 patients underwent revisions, some multiple. Only one infection occurred, seven months postoperatively, secondary to appendicitis with peritonitis. The infecting Streptococcus faecalis appeared to ascend from the abdominal cavity. Conclusion: A rigidly applied protocol and strict adherence to sterile technique can reduce shunt infections to a very low level. PMID:14707314

  13. Percutaneous ultrasound-guided insertion of ventriculo-atrial shunts.

    PubMed

    McCracken, James Albert; Bahl, Anuj; McMullan, John

    2016-08-01

    Ventriculo-atrial (VA) shunts have been in use for >60 years but less frequently so of late. This is due to a combination of the risk of cardiac complications, lack of expertise and a lengthy operation. We present our consecutive prospective series of 10 VA shunts inserted using a percutaneous method employing the Sonowand Invite™ neuronavigation system for both the distal and proximal catheters, over a 13-month period. We had two complications of cases needing revision, but our series highlights a safe and reproducible method of inserting a VA shunt. About 30% of the procedures were carried out by a trainee as the primary surgeon. This technique does not necessarily require the expertise of a complex hydrocephalus surgeon and is thus able to be in the armoury of any neurosurgeon needing to do a VA shunt procedure. The indications, operative data and outcomes of our patients are discussed.

  14. Shunting inhibitory cellular neural networks with chaotic external inputs

    NASA Astrophysics Data System (ADS)

    Akhmet, M. U.; Fen, M. O.

    2013-06-01

    Taking advantage of external inputs, it is shown that shunting inhibitory cellular neural networks behave chaotically. The analysis is based on the Li-Yorke definition of chaos. Appropriate illustrations which support the theoretical results are depicted.

  15. Shunting inhibitory cellular neural networks with chaotic external inputs.

    PubMed

    Akhmet, M U; Fen, M O

    2013-06-01

    Taking advantage of external inputs, it is shown that shunting inhibitory cellular neural networks behave chaotically. The analysis is based on the Li-Yorke definition of chaos. Appropriate illustrations which support the theoretical results are depicted.

  16. Routine cerebrospinal fluid analysis during 'de novo' ventriculoperitoneal shunt insertion: Single Institution Experience.

    PubMed

    Khalil, Ayman; Mandiwanza, Tafadzwa; Zakaria, Zaitun; Crimmins, Darach

    2016-08-01

    Background Cerebrospinal fluid (CSF) sampling is performed during ventriculoperitoneal (VP) shunting procedure surgery for early detection of infection. We have performed a retrospective study to determine whether routine intraoperative CSF sampling at new VP shunt insertion has predicted shunt infection or changed subsequent surveillance or management. Method From January 2011 to December 2013, 99 patients underwent first time VP shunt insertion at our hospital. The data collected from Beaumont Hospital Information System and operating theatre logbook. The reviewed data were patient demographics, the clinical condition requiring VP shunt procedure, shunt type, date of VP shunt insertion, date of VP shunt infection or malfunction and laboratory data. Results A first time VP shunt insertion procedure was performed in 99 patients. During the VP shunt insertion procedure, 64 patients had CSF sampling for microbiological analysis. The CSF culture was negative in all samples. All patients were followed up for 12 months. During the follow-up period, a total of 15 patients underwent VP shunt revision. Three of the shunt revisions were secondary to infection. The three infected shunt cases had sterile CSF cultures at the time of insertion. Conclusion There appears to be no correlation between CSF sampling during first time VP shunt insertion and the later development VP shunt infection. This questions the need for routine CSF sampling at the time of insertion. This would be confirmed as a part of future randomised trials.

  17. In vitro flow measurements in ion sputtered hydrocephalus shunts

    NASA Technical Reports Server (NTRS)

    Cho, Y. I.; Back, L. H.

    1989-01-01

    This paper describes an experimental procedure for accurate measurements of the pressure-drop/flow rate relationship in hydrocephalus shunts. Using a fish-hook arrangement, small flow rates in a perforated ion-sputtered Teflon microtubule were measured in vitro in a pressured system and were correlated with pressure in the system. Results indicate that appropriate drainage rates could be obtained in the physiological range for hydrocephalus shunts.

  18. Ventriculo-peritoneal shunt infection in a patient on hemodialysis.

    PubMed

    Thet, Yupar; Myint, Win; Myint, Wynne; Hughes, David; Crowe, Alex V; Banerjee, Anindya

    2008-07-01

    Sepsis is an important and serious complication in hemodialysis (HD) patients. Here we report on a case of spina bifida with ventriculo-peritoneal (VP) shunt infection who was on HD and underwent at least 5 months of investigations before a source of the infection was found and eventually treated successfully. We believe this to be the first reported case of VP shunt-associated sepsis in a patient on HD.

  19. Hearing Loss in Patients with Shunt-Treated Hydrocephalus.

    PubMed

    Panova, Margarita V; Geneva, Ina E; Madjarova, Kalina I; Bosheva, Miroslava N

    2015-01-01

    Hearing loss is a common manifestation of the long-term complications in patients with shunt treated hydrocephalus along with motor development disturbance, cognitive and visual impairment, epilepsy and endocrine disorders. The aim of the present study was to investigate the alterations of hearing in patients with shunt treated hydrocephalus of non-tumor etiology and at least one year after implantation of ventriculo-peritoneal shunt, as well as their impact on the quality of life of patients. The study included 70 patients (age range 1.25 years - 21.25 years) with shunted non-tumor hydrocephalus and at least one year after placement of the shunt system. Hearing alterations were proved by measuring the brainstem auditory evoked potentials (BAEP) for children up to 5 years of age and children with mental retardation; audiograms was used for children older than 5 years with normal neuro-psychological development (NPD). Of the 70 studied patients 17 (24%) had hearing loss (10 bilateral and 7-unilateral) and all of them had sensorineural hearing loss, which is associated with low weight at birth, posthemorrhagic hydrocephalus and brainstem symptoms at the time of diagnosis of hydrocephalus. Hearing pathology was found more often in shunt-treated patients with NPD retardation, poor functional status and low quality of life. Children with shunt-treated hydrocephalus have hearing loss of sensorineural type. Children with brain stem symptomatology at diagnosing hydrocephalus and children with post-hemorrhagic hydrocephalus show higher risk of hearing loss. Children with shunted hydrocephalus and hearing loss show lower NPD, lower quality of life and lower functional status.

  20. Hearing Loss in Patients with Shunt-Treated Hydrocephalus.

    PubMed

    Panova, Margarita V; Geneva, Ina E; Madjarova, Kalina I; Bosheva, Miroslava N

    2015-01-01

    Hearing loss is a common manifestation of the long-term complications in patients with shunt treated hydrocephalus along with motor development disturbance, cognitive and visual impairment, epilepsy and endocrine disorders. The aim of the present study was to investigate the alterations of hearing in patients with shunt treated hydrocephalus of non-tumor etiology and at least one year after implantation of ventriculo-peritoneal shunt, as well as their impact on the quality of life of patients. The study included 70 patients (age range 1.25 years - 21.25 years) with shunted non-tumor hydrocephalus and at least one year after placement of the shunt system. Hearing alterations were proved by measuring the brainstem auditory evoked potentials (BAEP) for children up to 5 years of age and children with mental retardation; audiograms was used for children older than 5 years with normal neuro-psychological development (NPD). Of the 70 studied patients 17 (24%) had hearing loss (10 bilateral and 7-unilateral) and all of them had sensorineural hearing loss, which is associated with low weight at birth, posthemorrhagic hydrocephalus and brainstem symptoms at the time of diagnosis of hydrocephalus. Hearing pathology was found more often in shunt-treated patients with NPD retardation, poor functional status and low quality of life. Children with shunt-treated hydrocephalus have hearing loss of sensorineural type. Children with brain stem symptomatology at diagnosing hydrocephalus and children with post-hemorrhagic hydrocephalus show higher risk of hearing loss. Children with shunted hydrocephalus and hearing loss show lower NPD, lower quality of life and lower functional status. PMID:27180348

  1. Small bowel perforation: a rare complication of ventriculoperitoneal shunt placement

    PubMed Central

    Bourm, Kelsey; Pfeifer, Cory; Zarchan, Adam

    2016-01-01

    Small bowel perforation is a rare complication of ventriculoperitoneal (VP) shunt placement. When seen, it most commonly affects the stomach or colon. We describe a case and image findings of an 8-year-old female who presented with sepsis and erosion of the VP shunt into the small bowel. The imaging findings were confirmed surgically. We also provide an overview of the current literature discussing previously reported cases, clinical features, and treatment.

  2. Disproportionately Enlarged Subarachnoid Space Hydrocephalus in Idiopathic Normal-Pressure Hydrocephalus and Its Implication in Pathogenesis.

    PubMed

    Ishikawa, Masaatsune; Oowaki, Hisayuki; Takezawa, Masahiro; Takenaka, Tomofumi; Yamada, Shigeki; Yamamoto, Kazuo; Okamoto, Shinichiro

    2016-01-01

    Idiopathic normal-pressure hydrocephalus (iNPH) has become socially significant in Japan. Japanese guidelines for iNPH in 2011 described the diagnostic importance of "disproportionately enlarged subarachnoid space hydrocephalus" (DESH) on magnetic resonance imaging (MRI). However, some patients with iNPH have equivocal or no features of DESH. To clarify the diversity of MRI findings in iNPH, we classified iNPH into three types based on MRI findings. Using this, we investigate predictable MRI findings for shunt effectiveness in iNPH. A total of 83 patients with suspected iNPH who were treated with shunt surgery were reviewed in this study. All patients had a positive cerebrospinal fluid (CSF) tap test. Among the 83 patients, DESH was noted in 64 %, incomplete DESH in 23 %, and no DESH in 13 % (see Fig. 3). Among the three types of incomplete DESH, incomplete DESH-v (ventricle) was 0 %, DESH-c (convexity) in 13 %, and DESH-s (Sylvian fissure) in 10 %. A high improvement rate after the shunt surgery was noted in the DESH and incomplete DESH-s groups, showing 73.5 % and 87.5 %, respectively. The non-DESH group showed a fairly large improvement of 63.6 %. A common MRI finding in DESH and incomplete DESH-s was high convexity tightness with ventriculomegaly. This combination was promising for shunt effectiveness in patients with suspected iNPH. Further study is necessary to elucidate the pathogenesis. PMID:27165923

  3. Design of an intelligent and personalised shunting system for hydrocephalus.

    PubMed

    Momani, Lina; Alkharabsheh, Abdel Rahman; Al-Nuaimy, Waleed

    2008-01-01

    Hydrocephalus is a neurological disease that manifests itself in an elevated fluid pressure within the brain, and if left untreated, may be fatal. It is currently treated using shunt implants, which consist of a mechanical valve and tubes that regulate the pressure of cerebrospinal fluid (CSF) by draining excess fluid into the abdomen. Hydrocephalus shunting systems are no longer expected simply to regulate the intracranial pressure (ICP), but also to offer the option of regaining independence of the shunt. Additionally, they could offer personalised valve management which is one of the main limitations of current shunts. This paper describes the design of a multi-agent system for an intelligent and personalised CSF management system. Patient feedback and intracranial pressure readings will play important roles in the process of CSF regulation and weaning, introduces an element of personalisation to the treatment. The new shunting system would deliver both reactive and goal-driven solutions for the treatment, at the same time the intelligent part of the system will be monitoring how well the shunt is performing. These tasks can be achieved by implementing an agent approach in designing this system. Such system would help us to understand more about the dynamics of hydrocephalus.

  4. First Report of Ventriculoperitoneal Shunt Infection due to Cyberlindnera fabianii

    PubMed Central

    Baghdadi, Jonathan; Hemarajata, Peera; Humphries, Romney; Kelesidis, Theodoros

    2015-01-01

    Fungal infections in the central nervous system (CNS) are associated with significant morbidity and death. Transient fungemia in immunocompetent patients without any other risk factors for fungemia has been suggested as a possible mechanism that may lead to serious fungal ventriculoperitoneal (VP) shunt infections, but evidence is lacking. The clinical spectrum, diagnosis, and optimal therapy of Cyberlindnera fabianii infections remain to be determined. We describe the first case of CNS infection due to C. fabianii that occurred in an immunocompetent adult with a VP shunt. Spontaneous translocation with yeast that is not part of the normal gastrointestinal flora in the setting of ingestion of multiple servings of a fermentation product was the likely source from which Cyberlindnera fabianii gained entrance into the VP shunt system, causing meningitis in this patient. The authors conclude that, in view of the high morbidity associated with yeast infection of the CNS, long-term antifungal therapy should be strongly considered in cases where the VP shunt cannot be completely removed. Transient fungemia may lead to invasive disease in an immunocompetent host with VP shunt, even in the absence of any other risk factors for fungemia and even after remote placement of the VP shunt. PMID:26618013

  5. Shunt switched resistor regulator with diode snubber

    SciTech Connect

    Ekstrand, J.

    1989-03-21

    This patent describes a shunt switched resistor regulator power supply for supplying a variable amount of power to a load comprising: a rectifier means for accepting AC input voltage and converting it to DC output voltage at a positive and a negative terminal; first, second, third, and fourth nodes wherein the first and the fourth nodes are coupled to the positive and negative terminals, respectively; a current limiting resistor coupled between the first and second nodes; a capacitor coupled between the second and fourth nodes; a resistor having parasitic inductance coupled between the second and third nodes; a switch coupled between the third and fourth nodes; and a diode having its anode coupled to the third node and having its cathode coupled to the second node; means coupled to the load terminals for sensing the power being delivered to the load and for controlling the switch to have a duty cycle which results in the desired load current flowing through and a desired voltage appearing across the load in accordance with control input signals received at a control input.

  6. Pathogenesis of Necrotizing Enterocolitis

    PubMed Central

    Tanner, Scott M.; Berryhill, Taylor F.; Ellenburg, James L.; Jilling, Tamas; Cleveland, Dava S.; Lorenz, Robin G.; Martin, Colin A.

    2016-01-01

    Necrotizing enterocolitis (NEC) is a major cause of morbidity and mortality in premature infants. The pathophysiology is likely secondary to innate immune responses to intestinal microbiota by the premature infant's intestinal tract, leading to inflammation and injury. This review provides an updated summary of the components of the innate immune system involved in NEC pathogenesis. In addition, we evaluate the animal models that have been used to study NEC with regard to the involvement of innate immune factors and histopathological changes as compared to those seen in infants with NEC. Finally, we discuss new approaches to studying NEC, including mathematical models of intestinal injury and the use of humanized mice. PMID:25447054

  7. Pathogenesis of varicose veins.

    PubMed

    Oklu, Rahmi; Habito, Roy; Mayr, Manuel; Deipolyi, Amy R; Albadawi, Hassan; Hesketh, Robin; Walker, T Gregory; Linskey, Katy R; Long, Chandler A; Wicky, Stephan; Stoughton, Julianne; Watkins, Michael T

    2012-01-01

    Despite the high prevalence of varicose veins and the recent surge in research on the condition, the precise mechanisms underlying their development remain uncertain. In the past decade, there has been a shift from initial theories based on purely mechanical factors to hypotheses pointing to complex molecular changes causing histologic alterations in the vessel wall and extracellular matrix. Despite progress in understanding the molecular aspects of venous insufficiency, therapies for symptomatic varicose veins are directed toward anatomic and physical interventions. The present report reviews current evidence identifying the underlying biochemical alterations in the pathogenesis of varicose veins.

  8. Pathogenesis of Tourette's syndrome.

    PubMed

    Leckman, J F; Peterson, B S; Anderson, G M; Arnsten, A F; Pauls, D L; Cohen, D J

    1997-01-01

    This review presents a models of disease pathogenesis in the context of CNS development. It begins with an exploration of the clinical features and natural history of Tourette's syndrome. This is followed by a consideration of the role of genetic and nongenetic factors. An effort is then made to review the anatomical organization of the basal ganglia and related cortical sites. These circuits are intimately involved in the normal processing of sensorimotor, cognitive, and emotionally laden information. Evidence implicating these circuits in the pathobiology of Tourette's syndrome is then considered. The review closes with the prospects for advances in interdisciplinary research and therapeutics using this model as a guide.

  9. [A case of repeated shunt malfunctions with eosinophilic meningitis caused by silicone allergy].

    PubMed

    Kambara, Mizuki; Miyazaki, Takeshi; Yoshikane, Tsutomu; Sugimoto, Keiji; Akiyama, Yasuhiko

    2014-12-01

    The ventricular-peritoneal shunt for hydrocephalus is a well-known and established method but is sometimes complicated by shunt malfunction due to several causes. Eosinophilic meningitis is a rare disease, but has occasionally been reported as a cause of shunt malfunction. Here, we report the case of a 74-year-old woman with repeated shunt malfunction and eosinophilic meningitis due to a silicone allergy. Originally, the patient received a ventricular-peritoneal shunt for normal pressure hydrocephalus secondary to subarachnoid hemorrhage. However, shunt malfunction was identified 6 weeks later, and the first shunt revision was performed using a new shunt system from a different company. Further evaluation to identify the cause of the shunt malfunction revealed no abnormal findings, except for eosinophilia in the serum and cerebrospinal fluid. A second shunt malfunction was identified 16 weeks after the first shunt revision. We therefore concluded that eosinophilic meningitis caused by a silicone allergy might be the real culprit and a second shunt revision was performed using a silicone "extracted" tube. Since then, the patient's course has been free from shunt malfunction. In this case, the serum and cerebrospinal fluid eosinophilia were useful markers for identifying the cause of repeated shunt malfunctions. The silicone "extracted" tube may be helpful for diagnosis and therapy.

  10. Temporary arterial shunts to maintain limb perfusion after arterial injury: an animal study

    NASA Technical Reports Server (NTRS)

    Dawson, D. L.; Putnam, A. T.; Light, J. T.; Ihnat, D. M.; Kissinger, D. P.; Rasmussen, T. E.; Bradley, D. V. Jr

    1999-01-01

    BACKGROUND: Temporary shunt placement can quickly restore perfusion after extremity arterial injury. This study examined the adequacy of limb blood flow with shunt use, non-heparin-bonded shunt patency over prolonged periods, and the safety of this technique. METHODS: Common iliac arteries were divided and 4.0-mm Silastic Sundt shunts placed in 16 anesthetized pigs. Eight (group I) had shunts placed immediately; eight others (group II) were shunted after an hour of limb ischemia and hemorrhagic shock. Physiologic parameters and femoral artery blood flow in both hindlimbs were continuously monitored. Limb lactic acid generation, oxygen utilization, and hematologic and metabolic effects were serially evaluated for 24 hours. RESULTS: Shunts remained patent in 13 of 16 pigs. Shunts thrombosed in two group I animals because of technical errors, but functioned well after thrombectomy and repositioning. Patency could not be maintained in one animal that died from shock. Flow in group I shunted limbs was 57 (+/-11 SD) % of control. For group II animals in shock, shunted limb flow initially averaged 46 +/- 15% of control, but 4 hours after shunt placement, the mean limb blood flow was the same as in group I. Increased oxygen extraction compensated for the lower flow. Lactic acid production was not increased in comparison to control limbs. CONCLUSION: Shunts provided adequate flow in this model of extremity trauma. Correctly placed shunts stayed patent for 24 hours, without anticoagulation, if shunt placement followed resuscitation.

  11. The right-to-left shunt of crocodilians serves digestion.

    PubMed

    Farmer, C G; Uriona, T J; Olsen, D B; Steenblik, M; Sanders, K

    2008-01-01

    Abstract All amniotes except birds and mammals have the ability to shunt blood past the lungs, but the physiological function of this ability is poorly understood. We studied the role of the shunt in digestion in juvenile American alligators in the following ways. First, we characterized the shunt in fasting and postprandial animals and found that blood was shunted past the lungs during digestion. Second, we disabled the shunt by surgically sealing the left aortic orifice in one group of animals, and we performed a sham surgery in another. We then compared postprandial rates of gastric acid secretion at body temperatures of 19 degrees and 27 degrees C and rates of digestion of bone at 27 degrees C. Twelve hours after eating, maximal rates of gastric acid secretion when measured at 19 degrees and 27 degrees C were significantly less in the disabled group than in sham-operated animals. Twenty-four hours postprandial, a significant decrease was found at 27 degrees C but not at 19 degrees C. For the first half of digestion, dissolution of cortical bone was significantly slower in the disabled animals. These data suggest the right-to-left shunt serves to retain carbon dioxide in the body so that it can be used by the gastrointestinal system. We hypothesize that the foramen of Panizza functions to enrich with oxygen blood that is destined for the gastrointestinal system to power proton pumps and other energy-demanding processes of digestion and that the right-to-left shunt serves to provide carbon dioxide to gastrointestinal organs besides the stomach, such as the pancreas, spleen, upper small intestine, and liver.

  12. Shunt insufficiency due to knot formation in the peritoneal catheter.

    PubMed

    Fekete, Gábor; Nagy, Andrea; Pataki, István; Bognar, László; Novák, László

    2013-07-30

    The authors report a rare case of the peripheral obstruction of a ventriculoperitoneal shunt. Premature baby was operated on hydrocephalus due to germinal matrix bleeding. After two months of implantation of venticuloperitoneal shunt peripheral insufficiency of the system was emerged. During the shunt revision extensive knot formation became visible. We simply cut the catheter above the knot and the working shunt was replaced into the abdominal cavity. The postoperative course was uneventful and the baby was free of complaints for more than one year. The pathomechanism of knot formation is not clear thus the discovery of the problem during the operation is an unexpected event. In our opinion tight knot cannot be spontaneously formed intraabdominally. Loose knots can be developed and can reduce the capacity of liquor flow. We think that the knot tightens during pulling out. Longer peritoneal catheters can precipitate multiple looping and/or axial torquations and increase the peripheral resistance of the shunt. In such cases when the pulling out is challenged conversion to laparotomy is suggested.

  13. Favorable results with syringosubarachnoid shunts for treatment of syringomyelia.

    PubMed

    Tator, C H; Meguro, K; Rowed, D W

    1982-04-01

    From 1969 to 1979, 20 patients with syringomyelia were treated with a syringosubarachnoid shunt. The principal indications for this procedure were: significant progressive neurological deterioration and absent or minimal tonsillar ectopia. There were 15 patients with idiopathic syringomyelia, four with posttraumatic syringomyelia, and one with syringomyelia secondary to spinal arachnoiditis. The operations were performed with an operating microscope, and attention was directed to preserving thearachnoid membrane to ensure proper placement of the distal end of the shunt in an intact subarachnoid space. In all cases, a silicone rubber ventricular catheter was inserted into the syrinx through a posterior midline myelotomy. The average follow-up period was 5 years. A favorable result was obtained in 15 of the 20 patients (75%), including an excellent result with improvement of neurological deficit in 11 patients and a good result with cessation of progression in four patients. In the remaining five patients the result was poor with further progression of neurological deficit. A short duration of preoperative symptoms was usually a favorable prognostic feature. Four patients with a history of less than 6 months all had excellent results. Thirteen patients had a syringosubarachnoid shunt only, and all had good or excellent results. Seven patients had other surgical procedures, before, accompanying, or after shunt placement, and two had favorable results. Thus, the syringosubarachnoid shunt is an effective therapeutic modality for many patients with syringomyelia, particularly if there is little or no tonsillar herniation.

  14. A simplified technique of performing splenorenal shunt (Omar's technique).

    PubMed

    Shah, Omar Javed; Robbani, Irfan

    2005-01-01

    The splenorenal shunt procedure introduced by Robert Linton in 1947 is still used today in those regions of the world where portal hypertension is a common problem. However, because most surgeons find Linton's shunt procedure technically difficult, we felt that a simpler technique was needed. We present the surgical details and results of 20 splenorenal anastomosis procedures performed within a period of 30 months. Half of the patients (Group I) underwent Linton's conventional technique of splenorenal shunt; the other half (Group II) underwent a newly devised, simplified shunt technique. This new technique involves dissection of the fusion fascia of Toldt. The outcome of the 2 techniques was identical with respect to the reduction of preshunt portal pressure. However, our simplified technique was advantageous in that it significantly reduced the duration of surgery (P <0.001) and the amount of intraoperative blood loss (P <0.003). No patient died after either operation. Although Linton's splenorenal shunt is difficult and technically demanding, it is still routinely performed. The new technique described here, in addition to being simpler, helps achieve good vascular control, permits easier dissection of the splenic vein, enables an ideal anastomosis, decreases intraoperative blood loss, and reduces the duration of surgery. Therefore, we recommend the routine use of this simplified technique (Omar's technique) for the surgical treatment of portal hypertension. PMID:16429901

  15. An overview of the literature on congenital lower urinary tract obstruction and introduction to the PLUTO trial: percutaneous shunting in lower urinary tract obstruction.

    PubMed

    Morris, R Katie; Kilby, Mark D

    2009-02-01

    Congenital lower urinary tract obstruction (LUTO) comprises a heterogeneous group of pathologies causing obstruction to the urethra, the most common being posterior urethral valves. Such pathology is often associated with high perinatal mortality and varying degrees of perinatal and infant morbidity. A high proportion of LUTO may be visualised during routine second trimester (and first trimester) ultrasound giving rise to the possibility of determining individual fetal prognosis and treatments such as vesico-amniotic shunting, with a view to altering pathogenesis. The aims of the percutaneous shunting in low urinary tract obstruction (PLUTO) trial are to determine the effectiveness of these treatments and accuracy of the investigations with the primary outcome measures being perinatal mortality and postnatal renal function. PMID:19281572

  16. An overview of the literature on congenital lower urinary tract obstruction and introduction to the PLUTO trial: percutaneous shunting in lower urinary tract obstruction.

    PubMed

    Morris, R Katie; Kilby, Mark D

    2009-02-01

    Congenital lower urinary tract obstruction (LUTO) comprises a heterogeneous group of pathologies causing obstruction to the urethra, the most common being posterior urethral valves. Such pathology is often associated with high perinatal mortality and varying degrees of perinatal and infant morbidity. A high proportion of LUTO may be visualised during routine second trimester (and first trimester) ultrasound giving rise to the possibility of determining individual fetal prognosis and treatments such as vesico-amniotic shunting, with a view to altering pathogenesis. The aims of the percutaneous shunting in low urinary tract obstruction (PLUTO) trial are to determine the effectiveness of these treatments and accuracy of the investigations with the primary outcome measures being perinatal mortality and postnatal renal function.

  17. Pathogenesis of pituitary tumors.

    PubMed

    Yu, Run; Melmed, Shlomo

    2010-01-01

    Pituitary tumors are common and mostly benign neoplasia which cause excess or deficiency of pituitary hormones and compressive damage to adjacent organs. Oncogene activation [e.g. PTTG (pituitary tumor-transforming gene) and HMGA2], tumor suppressor gene inactivation (e.g. MEN1 and PRKAR1A), epigenetic changes (e.g. methylation) and humoral factors (e.g. ectopic production of stimulating hormones) are all possible pituitary tumor initiators; the micro-environment of pituitary tumors including steroid milieu, angiogenesis and abnormal cell adhesion further promote tumor growth. Senescence, a cellular defence mechanism against malignant transformation, may explain the benign nature of at least some pituitary tumors. We suggest that future research on pituitary tumor pathogenesis should incorporate systems approaches, and address regulatory mechanisms for pituitary cell proliferation, development of new animal models of pituitary tumor and isolation of functional human pituitary tumor cell lines. PMID:20541667

  18. Pathogenesis of infantile haemangioma.

    PubMed

    Greenberger, S; Bischoff, J

    2013-07-01

    Haemangioma is a vascular tumour of infancy that is well known for its rapid growth during the first weeks to months of a child's life, followed by a spontaneous but slow involution. During the proliferative phase, the vessels are disorganized and composed of immature endothelial cells. When the tumour involutes, the vessels mature and enlarge but are reduced in number. Fat, fibroblasts and connective tissue replace the vascular tissue, with few, large, feeding and draining vessels evident. Both angiogenesis and vasculogenesis have been proposed as mechanisms contributing to the neovascularization in haemangioma tumours. In recent years, several of the 'building blocks', the cells comprising the haemangioma, have been isolated. Among them are haemangioma progenitor/stem cells, endothelial cells and pericytes. This review focuses on these cell types, and the molecular pathways within these cells that have been implicated in driving the pathogenesis of infantile haemangioma.

  19. Pathogenesis of glomerular haematuria.

    PubMed

    Yuste, Claudia; Gutierrez, Eduardo; Sevillano, Angel Manuel; Rubio-Navarro, Alfonso; Amaro-Villalobos, Juan Manuel; Ortiz, Alberto; Egido, Jesus; Praga, Manuel; Moreno, Juan Antonio

    2015-05-01

    Haematuria was known as a benign hallmark of some glomerular diseases, but over the last decade, new evidences pointed its negative implications on kidney disease progression. Cytotoxic effects of oxidative stress induced by hemoglobin, heme, or iron released from red blood cells may account for the tubular injury observed in human biopsy specimens. However, the precise mechanisms responsible for haematuria remain unclear. The presence of red blood cells (RBCs) with irregular contours and shape in the urine indicates RBCs egression from the glomerular capillary into the urinary space. Therefore glomerular haematuria may be a marker of glomerular filtration barrier dysfunction or damage. In this review we describe some key issues regarding epidemiology and pathogenesis of haematuric diseases as well as their renal morphological findings. PMID:25949932

  20. Fungal Sex and Pathogenesis

    PubMed Central

    Butler, Geraldine

    2010-01-01

    Summary: Human fungal pathogens are associated with diseases ranging from dandruff and skin colonization to invasive bloodstream infections. The major human pathogens belong to the Candida, Aspergillus, and Cryptococcus clades, and infections have high and increasing morbidity and mortality. Many human fungal pathogens were originally assumed to be asexual. However, recent advances in genome sequencing, which revealed that many species have retained the genes required for the sexual machinery, have dramatically influenced our understanding of the biology of these organisms. Predictions of a rare or cryptic sexual cycle have been supported experimentally for some species. Here, I examine the evidence that human pathogens reproduce sexually. The evolution of the mating-type locus in ascomycetes (including Candida and Aspergillus species) and basidiomycetes (Malassezia and Cryptococcus) is discussed. I provide an overview of how sex is suppressed in different species and discuss the potential associations with pathogenesis. PMID:20065328

  1. Molecular Pathogenesis of NASH

    PubMed Central

    Caligiuri, Alessandra; Gentilini, Alessandra; Marra, Fabio

    2016-01-01

    Nonalcoholic steatohepatitis (NASH) is the main cause of chronic liver disease in the Western world and a major health problem, owing to its close association with obesity, diabetes, and the metabolic syndrome. NASH progression results from numerous events originating within the liver, as well as from signals derived from the adipose tissue and the gastrointestinal tract. In a fraction of NASH patients, disease may progress, eventually leading to advanced fibrosis, cirrhosis and hepatocellular carcinoma. Understanding the mechanisms leading to NASH and its evolution to cirrhosis is critical to identifying effective approaches for the treatment of this condition. In this review, we focus on some of the most recent data reported on the pathogenesis of NASH and its fibrogenic progression, highlighting potential targets for treatment or identification of biomarkers of disease progression. PMID:27657051

  2. Fungal sex and pathogenesis.

    PubMed

    Butler, Geraldine

    2010-01-01

    Human fungal pathogens are associated with diseases ranging from dandruff and skin colonization to invasive bloodstream infections. The major human pathogens belong to the Candida, Aspergillus, and Cryptococcus clades, and infections have high and increasing morbidity and mortality. Many human fungal pathogens were originally assumed to be asexual. However, recent advances in genome sequencing, which revealed that many species have retained the genes required for the sexual machinery, have dramatically influenced our understanding of the biology of these organisms. Predictions of a rare or cryptic sexual cycle have been supported experimentally for some species. Here, I examine the evidence that human pathogens reproduce sexually. The evolution of the mating-type locus in ascomycetes (including Candida and Aspergillus species) and basidiomycetes (Malassezia and Cryptococcus) is discussed. I provide an overview of how sex is suppressed in different species and discuss the potential associations with pathogenesis. PMID:20065328

  3. Microbial pathogenesis meets biomechanics.

    PubMed

    Charles-Orszag, Arthur; Lemichez, Emmanuel; Tran Van Nhieu, Guy; Duménil, Guillaume

    2016-02-01

    Introducing concepts from soft matter physics and mechanics has largely contributed to our understanding of a variety of biological processes. In this review, we argue that this holds true for bacterial pathogenesis. We base this argument on three examples of bacterial pathogens and their interaction with host cells during infection: (i) Shigella flexneri exploits actin-dependent forces to come into close contact with epithelial cells prior to invasion of the epithelium; (ii) Neisseria meningitidis manipulates endothelial cells to resist shear stress during vascular colonization; (iii) bacterial toxins take advantage of the biophysical properties of the host cell plasma membrane to generate transcellular macroapertures in the vascular wall. Together, these examples show that a multidisciplinary approach integrating physics and biology is more necessary than ever to understand complex infectious phenomena. Moreover, this avenue of research will allow the exploration of general processes in cell biology, highlighted by pathogens, in the context of other non-communicable human diseases. PMID:26849533

  4. The pathogenesis of measles.

    PubMed

    de Vries, Rory D; Mesman, Annelies W; Geijtenbeek, Teunis B H; Duprex, W Paul; de Swart, Rik L

    2012-06-01

    Measles is an important cause of childhood morbidity and mortality in developing countries. Measles virus (MV) is transmitted via the respiratory route and causes systemic disease. Over the last decade, identification of new cellular receptors and studies in animal models have challenged the historic concepts of measles pathogenesis. It is thought that MV enters the host by infection of alveolar macrophages and/or dendritic cells in the airways, and is amplified in local lymphoid tissues. Viremia mediated by infected CD150+ lymphocytes results in systemic dissemination. Infection of lymphocytes and dendritic cells in the respiratory submucosa facilitates basolateral infection of epithelial cells via the newly identified receptor Nectin-4. Concomitant and extensive epithelial damage may contribute to efficient transmission to the next host.

  5. Molecular pathogenesis of emphysema

    PubMed Central

    Taraseviciene-Stewart, Laimute; Voelkel, Norbert F.

    2008-01-01

    Emphysema is one manifestation of a group of chronic, obstructive, and frequently progressive destructive lung diseases. Cigarette smoking and air pollution are the main causes of emphysema in humans, and cigarette smoking causes emphysema in rodents. This review examines the concept of a homeostatically active lung structure maintenance program that, when attacked by proteases and oxidants, leads to the loss of alveolar septal cells and airspace enlargement. Inflammatory and noninflammatory mechanisms of disease pathogenesis, as well as the role of the innate and adaptive immune systems, are being explored in genetically altered animals and in exposure models of this disease. These recent scientific advances support a model whereby alveolar destruction resulting from a coalescence of mechanical forces, such as hyperinflation, and more recently recognized cellular and molecular events, including apoptosis, cellular senescence, and failed lung tissue repair, produces the clinically recognized syndrome of emphysema. PMID:18246188

  6. [Pathogenesis of rheumatoid arthritis].

    PubMed

    Branimir Anić; Miroslav Mayer

    2014-01-01

    Rheumatoid arthritis (RA) is an autoimmune systemic disease that primarily affects joints. Etiology and the pathogenesis of RA are complex, involving many types of cells, among others macrophages, T and B cells, fibro- blasts, chondrocytes and dendritic cells. Despite well documented role of many genes and epigenetic modifications in the development and evolution of the disease, in most RA patients there is no clear predisposing factor present. Environmental factors involved in RA pathogenesis are cigarette smoke, industrial pollutants like silica crystals, disturbances of intestinal, lung, and oral microbiota and some specific bacterial and viral infectious agents and their components. In the initial disease stage there are qualitative and quantitative disturbances ofpeptide citrulination as well as other protein modifications, followed by antigen presenting cell (APC) (macrophages and dendritic cells) and fibroblast like synoviocytes (FLS) activation. Some microbes foster this processes by APC and FLS direct and indirect activation. In the second stage APC's elicit specific humoral B cell re- sponse resulting in specific antibodies production and T cell autoreactivity. Inherited and acquired defects in T and B cell responses caused by repeated activation of innate immunity as well as loss of tolerance, elicit chronic autoimmune inflammation, primarily of synovial membranes, and development of cellular panus. Pathologic activation of the osteoclasts and release of the immune system effector molecules and the proteolytic enzymes damage the cartilage, bone and tendons composition and structure. Persistent inflammation through its complex mechanisms results in many systemic and extraarticular RA manifestations of almost all organ systems, resulting in severe complications and comorbidities such as rheumatoid lung, carditis, vasculitis, cahexia, anemia, accelerated atherosclerosis, myocardial and cerebrovascular vascular disease, lymphoma, osteoporosis, depression etc

  7. A Subglandular Breast Cerebrospinal Fluid Pseudocyst Following Postsurgical Shunt Migration

    PubMed Central

    Mlynek, Karolina; Frautschi, Russell; Halasa, Brianna; Kwiecien, Grzegorz

    2015-01-01

    Summary: Cerebrospinal fluid (CSF) drainage catheters have been associated with numerous complications in various anatomic locations, because of migration, infection, and obstruction. However, breast-related CSF shunt complications tend to occur infrequently or have seldom been reported in the empirical literature. Therefore, a case is presented detailing a breast pseudocyst caused by migration and subsequent coiling of a ventriculoperitoneal shunt in the right breast pocket. To the best of the authors’ knowledge, this is the first case that has been reported in the peer-reviewed literature of a pseudocyst resulting from a CSF drainage catheter coiling around the breast implant post pancreaticoduodenectomy. Moreover, this case highlights the importance of cross-disciplinary procedural awareness, particularly in regards to breast, ventriculoperitoneal shunt, and pancreatic procedures. PMID:26894004

  8. Temporal and spatial distributions of carbon shunting arc plasma

    NASA Astrophysics Data System (ADS)

    Takaki, Koichi; Konishi, Takumi; Mikawa, Ryota; Takahashi, Kazunori; Yukimura, Ken

    2015-01-01

    The temporal and spatial distributions of a magnetically driven shunting arc plasma were obtained using time-resolved probe measurement. A shunting arc was produced using a carbon rod and accelerated along a pair of rail electrodes by a Lorenz force. The pulse current for driving and maintaining the plasma was supplied from a 20 µF capacitor charged by a dc power supply. Double and single probes were employed to obtain the ion density of the shunting arc plasma. An ion density of 1 × 1019 m-3 was obtained at a distance of 50 mm from the carbon rod 15 µs after applying voltage. The ion density decreased to 2.0 × 1018 m-3 with increasing distance from 50 to 150 mm. The ion density changed with the energy inputted into the plasma.

  9. Executive function improvement in normal pressure hydrocephalus following shunt surgery.

    PubMed

    Gleichgerrcht, Ezequiel; Cervio, Andrés; Salvat, Jorge; Loffredo, Anselmo Rodríguez; Vita, Luciana; Roca, María; Torralva, Teresa; Manes, Facundo

    2009-01-01

    The aim of this investigation was to evaluate improvement of executive functions after shunt surgery in patients with early normal pressure hydrocephalus (NPH). Patients with NPH were assessed before and after shunt surgery with tests shown to be sensitive to damage to the prefrontal cortex (PFC). Significant differences were found between basal and follow-up performances on the Boston Naming Test, the backwards digits span, Part B of the Trail Making Test, and the number of words produced on the phonological fluency task. In conclusion, our study reveals that patients with NPH who respond positively to continuous slow lumbar cerebral spinal fluid drainage and receive a ventriculoperitoneal shunt implant, improve their performance on tasks of executive function. Due to the high demand for this form of mental processing in real-life complex scenarios, and based on the severe executive deficits present in both demented and non-demented NPH patients, we encourage the assessment of executive functions in this clinical group.

  10. Intraperitoneal cerebrospinal fluid pseudocyst. A rare complication of ventriculoperitoneal shunt.

    PubMed

    Birbilis, Th; Kontogianidis, K; Matis, G; Theodoropoulou, E; Efremidou, E; Argyropoulou, P

    2008-01-01

    The abdominal intraperitoneal cerebrospinal fluid pseudocyst is a rare but important complication in patients with ventriculoperitoneal shunts. We report a case of a 31-year-old female, in which a large abdominal pseudocyst was developed 1 year after insertion of a ventriculoperitoneal shunt for hydrocephalus. The abdominal CT scan and the ultrasonographical evaluation of the abdomen showed a well defined, cystic mass lesion with a volume of 50 cm3, in the recessus hepato-renal. The peritoneal tip of the shunt was located within the mass lesion. A distal externalization of the peritoneal catheter without excision of the pseudocyst was performed. Cerebrospinal fluid culture demonstrated a Staphylococcus epidermis infection and adequate antibiotic treatment was administrated. The previous symptoms improved 4 weeks later and a new catheter was placed intraperitoneally in a different quadrant. The postoperative course was uneventful. We suggest that chronic inflammation or subclinical peritonitis is a predisposing factor for this complication. PMID:18717287

  11. Delayed intracerebellar hemorrhage secondary to lumboperitoneal shunt insertion

    PubMed Central

    Er, Uygur; Akyol, Çetin; Bavbek, Murad

    2016-01-01

    Aim of this paper is to present and discuss a case of a delayed cerebellar parenchymal hemorrhage developing after L/P shunt placement with a NPH patient. A hypertensive patient admitted to our clinic with a diagnosis of NPH. The patient was placed a pressure adjustable L/P shunt without any surgical complication. He was discharged with an uneventful period. The patient was admitted to the emergency clinic of our hospital with a 1.5 × 1.5 cm diameter hematoma at the left cerebellar hemisphere on 2 days after his discharge. CSF drainage by an L/P shunt can generate intracerebellar hemorrhages especially in hypertensive patients. PMID:27695558

  12. Rare sequelae following ventriculoatrial shunt: Case report and review of literature

    PubMed Central

    Gopal, Vinu Venu; Peethambaran, Anil Kumar

    2016-01-01

    Ventriculoatrial shunt (VA) is one of the oldest solutions for hydrocephalus. However over subsequent years various complication of VA shunt such as obstructions, malposition, shunt infections, cardiac complications such as endocarditis, traumatic perforation, heart failure, tricuspid regurgitation, intraatrial thrombus, and pulmonary hypertension are reported. Hence, VA shunt procedure has fallen into disrepute. Still VA shunt may be a good option in selected patients with hostile peritoneum. Newer placement strategies and monitoring methods have been put forward to reduce complication following VA shunt. In this case report, we share a rare case of endocarditis with tricuspid regurgitation following a migrated retained calcified shunt tube in the right ventricle of heart 30 years after of VA shunt that was successfully managed. PMID:27057231

  13. Breast-related CSF shunt complications: literature review with illustrative case.

    PubMed

    Schrot, Rudolph J; Ramos-Boudreau, Christine; Boggan, James E

    2012-09-01

    In this article, we discuss and classify breast-related ventriculoperitoneal (VP) cerebrospinal fluid (CSF) shunt complications, and provide a literature review. Shunt complications related to pre-existing breast implants comprise nearly half of the breast-related shunt complications reported thus far. We present a complication of shunt failure in a 61-year-old woman who had previously undergone mastectomies for breast cancer with implant reconstruction. Following shunting, she developed headaches, fever, and right-sided breast swelling and erythma consequent to breast implant rupture, distal shunt migration, and CSF pseudocyst. This case is unique in that it involved rupture of a breast implant from VP shunt insertion. For complication avoidance, neurosurgeons should be aware of the potential pitfalls in shunting patients with breast implants.

  14. Time-related patterns of ventricular shunt failure.

    PubMed

    Kast, J; Duong, D; Nowzari, F; Chadduck, W M; Schiff, S J

    1994-11-01

    Proximal obstruction is reported to be the most common cause of ventriculoperitoneal (VP) shunt failure, suggesting that imperfect ventricular catheter placement and inadequate valve mechanisms are major causes. This study retrospectively examined patterns of shunt failure in 128 consecutive patients with symptoms of shunt malfunction over a 2-year period. Factors analyzed included site of failure, time from shunt placement or last revision to failure, age of patient at time of failure, infections, and primary etiology of the hydrocephalus. One hundred of these patients required revisions; 14 revisions were due to infections. In this series there was a higher incidence of distal (43%) than of proximal (35%) failure. The difference was not statistically significant when the overall series was considered; however, when factoring time to failure as a variable, marked differences were noted regardless of the underlying cause of hydrocephalus or the age of the patient. Of the 49 patients needing a shunt revision or replacement within 2 years of the previous operation, 50% had proximal malfunction, 14% distal, and 10% had malfunctions attributable directly to the valve itself. Also, 12 of the 14 infections occurred during this time interval. In sharp contrast, of the 51 patients having shunt failure from 2 to more than 12 years after the previous procedure, 72% had distal malfunction, 21% proximal, and only 6% had a faulty valve or infection. This difference between time to failure for proximal versus distal failures was statistically significant (P < 0.00001 for both Student's t-test and non-parametric Mann-Whitney U-test).(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Utility of Operative Glaucoma Tube Shunt Viscoelastic Bolus Flush

    PubMed Central

    Groth, Sylvia L; Greider, Kelsi L

    2015-01-01

    ABSTRACT Objective: To assess the utility of viscoelastic injection to induce bleb expansion and decrease intraocular pressure (IOP) in eyes with encapsulated glaucoma tube shunt blebs. Design: Case series. Subjects and participants: Forty-three glaucomatous eyes, including 13 eyes with congenital, 13 uveitic, 5 neovascular, 5 open angle, 4 narrow angle and 3 traumatic glaucomas. Methods, interventions or testing: All patients underwent viscoelastic flush procedure. A pre-bent 27 or 30-gauge cannula was passed through a 25-gauge paracentesis, advanced over the iris across the anterior chamber, and insinuated into the tube shunt lumen. Once the cannula was firmly lodged in position, 0.45 to 0.85 ml of viscoelastic was injected to hyperinflate the bleb. Main outcome measures: Paired t-tests were performed comparing preoperative IOP and number of medications used preoperatively vs levels measured at 1, 6, 12, 18 and 24 months. Results: Intraocular pressure was reduced from a mean preoperative level of 26.0 ± 1.2 (sem) mm Hg to 15.8 ± 1.0 at 1 month, remaining stable thereafter at each 6-month interval with 15.1 ± 1.1 mm Hg at 24 months (p < 0.0001). Medication use did not vary significantly from baseline. Pressure remained < 21 mm Hg after 2 years in 85% of eyes cannulated within 1 year of primary tube shunt implantation (n = 23), and in 62% of eyes cannulated more than 1 year after tube shunt placement (n = 20). Conclusion: Tube shunt expansion with bolus viscoelastic flush successfully restored encapsulated bleb function, providing a substantial (~10 mm Hg) IOP decrease into the mid-normal pressure range. This persisted in the majority of treated eyes for the entire study period. How to cite this article: Groth SL, Greider KL, Sponsel WE. Utility of Operative Glaucoma Tube Shunt Viscoelastic Bolus Flush. J Curr Glaucoma Pract 2015;9(3):73-76. PMID:26997840

  16. In Vitro and In Vivo Comparison of Two Suprachoroidal Shunts

    PubMed Central

    Oatts, Julius T.; Zhang, Ze; Tseng, Harry; Shields, M. Bruce; Sinard, John H.; Loewen, Nils A.

    2013-01-01

    Purpose. To compare fibrosis, aqueous humor dynamics, and intraocular pressure (IOP) of two suprachoroidal shunts as part of a new class of glaucoma drainage devices. Methods. Following proliferation analysis in vitro, 20 rabbits were implanted with either a gold shunt (GS, GMSplus+, SOLX) or a polypropylene shunt (PS, Aquashunt, OPKO). Ten eyes received mitomycin C (MMC) and triamcinolone. Peak and trough IOP were monitored with a pneumatonometer and tono-pen for 15 weeks. Aqueous humor dynamics were evaluated fluorophotometrically and tonographically. Fibrosis was quantified. Results. In vitro proliferation was similar. In vivo, both shunts were devoid of foreign body reaction but exhibited fibrosis, and GS showed vascularization. There was no significant difference in aqueous or uveoscleral flow. Preoperative morning IOP was 23.7 ± 2 mm Hg, and evening IOP was 26.5 ± 2 mm Hg (P = 0.000). Morning IOP was decreased through 15 weeks and evening IOP through 8 weeks in all groups. The morning IOP decrease was most profound at 15 weeks in PS (41%) compared to GS (18%). Antifibrotics initially enhanced but eventually diminished shunt performance. At 15 weeks, thickness of scleral fibrosis was greater in GS (246 ± 47 μm) and PS (188 ± 47 μm, P = 0.285) compared with GS+MMC (109 ± 26 μm, P = 0.023 to GS) and PS+MMC (48 ± 30 μm, P = 0.028 to PS). Conclusions. In a rabbit model, suprachoroidal polypropylene and gold shunts allow access to a new drainage pathway with different IOP profiles that can be modified with antifibrotics. PMID:23847318

  17. Shunted Piezoelectric Vibration Damping Analysis Including Centrifugal Loading Effects

    NASA Technical Reports Server (NTRS)

    Min, James B.; Duffy, Kirsten P.; Provenza, Andrew J.

    2011-01-01

    Excessive vibration of turbomachinery blades causes high cycle fatigue problems which require damping treatments to mitigate vibration levels. One method is the use of piezoelectric materials as passive or active dampers. Based on the technical challenges and requirements learned from previous turbomachinery rotor blades research, an effort has been made to investigate the effectiveness of a shunted piezoelectric for the turbomachinery rotor blades vibration control, specifically for a condition with centrifugal rotation. While ample research has been performed on the use of a piezoelectric material with electric circuits to attempt to control the structural vibration damping, very little study has been done regarding rotational effects. The present study attempts to fill this void. Specifically, the objectives of this study are: (a) to create and analyze finite element models for harmonic forced response vibration analysis coupled with shunted piezoelectric circuits for engine blade operational conditions, (b) to validate the experimental test approaches with numerical results and vice versa, and (c) to establish a numerical modeling capability for vibration control using shunted piezoelectric circuits under rotation. Study has focused on a resonant damping control using shunted piezoelectric patches on plate specimens. Tests and analyses were performed for both non-spinning and spinning conditions. The finite element (FE) shunted piezoelectric circuit damping simulations were performed using the ANSYS Multiphysics code for the resistive and inductive circuit piezoelectric simulations of both conditions. The FE results showed a good correlation with experimental test results. Tests and analyses of shunted piezoelectric damping control, demonstrating with plate specimens, show a great potential to reduce blade vibrations under centrifugal loading.

  18. Fetal ovarian cyst mimicking a CSF pseudocyst in the setting of shunt failure.

    PubMed

    Calayag, Mark; Malone, Christian Cantillano; Drake, Brian; Chavhan, Govind; Rutka, James T

    2015-01-01

    Fetal ovarian cysts are common congenital lesions encountered in the neonatal population. These cysts are typically benign and rarely require any invasive intervention. Abdominal pseudocyst formation as a result of a ventriculoperitoneal shunt is a relatively infrequent occurrence and is similarly an uncommon cause of shunt failure. The authors present the case of a 4-month-old girl with shunted hydrocephalus who presented with shunt failure from a suspected abdominal pseudocyst that was found to be a fetal ovarian cyst.

  19. Ventriculoperitoneal shunt complications in hydrocephalus patients with intracranial tumors: an analysis of relevant risk factors.

    PubMed

    Reddy, G Kesava; Bollam, Papireddy; Caldito, Gloria; Willis, Brian; Guthikonda, Bharat; Nanda, Anil

    2011-06-01

    Patients with intracranial tumors are predisposed to persistent hydrocephalus, often requiring a permanent CSF diversion procedure with shunts. This study reviews the long-term experience with ventriculoperitoneal shunts for the management of hydrocephalus in patients with intracranial tumors. Patients with intracranial tumors who underwent ventriculoperitoneal shunt placement for hydrocephalus from October 1990 to October 2009 were included in this study. During the 19-year period, medical charts, operative reports, imaging studies, and clinical follow- up evaluations were reviewed and analyzed retrospectively for all patients. A total of 187 intracranial tumor patients with hydrocephalus were included. The median follow up was 391 days. Malignant tumors were present in 40% of the patients. Overall shunt failure was 27.8%. Single shunt revision occurred in 13% of the patients and 14% had multiple shunt revision. Tumor histology, age and a procedure prior to shunt placement (ventriculostomy/Ommaya reservoirs) were significantly associated with the shunt revisions. Shunt system replacement and proximal shunt complication were significantly attributed to multiple shunt revisions. The overall shunt revision within 3 months, 6 months, 1 year and 5 years was 17.7%, 18.7%, 19.8% and 24.1%, respectively. The results of the study demonstrate that VP shunting is an effective for the management of hydrocephalus in patients with intracranial tumors. The overall incidence of shunt revision was 27.8%. Age, tumor histology, and a procedure prior to shunt placement (ventriculostomy/Ommaya reservoirs) were significantly associated with the shunt revisions. Additional studies using minimally invasive techniques are being explored for the management of hydrocephalus in patients with intracranial tumors.

  20. Endophthalmitis associated with Glaucoma Shunt Intraluminal Stent Exposure.

    PubMed

    Kwon, Hye Jin; Kerr, Nathan M; Ruddle, Jonathan B; Ang, Ghee Soon

    2016-01-01

    Endophthalmitis post glaucoma drainage implant (GDI) surgery is rare, often associated with tube or plate exposure. We report a case of endophthalmitis following glaucoma shunt intraluminal stent exposure in a patient who underwent Baerveldt glaucoma implant surgery. Endophthalmitis following manipulation of intraluminal stents is a rare complication of GDIs but potentially vision threatening condition that needs to be carefully screened for and treated immediately. How to cite this article: Kwon HJ, Kerr NM, Ruddle JB, Ang GS. Endophthalmitis associated with Glaucoma Shunt Intraluminal Stent Exposure. J Curr Glaucoma Pract 2016;10(1):36-37.

  1. CSF shunts 50 years on--past, present and future.

    PubMed

    Drake, J M; Kestle, J R; Tuli, S

    2000-11-01

    Cerebrospinal fluid (CSF) shunts were invented almost 50 years ago. While their introduction revolutionized the treatment of hydrocephalus, their complications have become legendary, and the focus of much investigation and development of new devices. New devices have been based upon improved understanding of the pathophysiology of hydrocephalus or shunt complications. Despite the rational, or frequently "more physiological," functioning of these devices, all too often unexpected complications have ensued, and the initial enthusiasm for the devices has waned. Assessing the efficacy of the devices has been difficult, owing to the lack of properly conducted studies. Nevertheless, the overall impact of shunt design improvements has seemed very limited. A recent randomized trial of CSF shunt design, examining the failure rates of two new and widely used valves (the Cordis Orbis Sigma and the Medtronic PS Medical Delta valves) failed to find any advantage of these over standard valve designs, many of which have been used almost since the inception of CSF shunts. A search for risk factors for failure, in a post hoc analysis of the data, indicated only that the etiology of the hydrocephalus and the position and local environment of the ventricular catheter tip were probably important. Remarkably, the rate of change in the size of the ventricles and the final ventricular size were not different despite the substantial differences in flow characteristics of the two new valves. Shunt failure rates of less than 5% at 1 year, with infection rates of less than 1%, seem like reasonable goals for the next decade in the new millenium. This can be achieved through basic research into the pathophysiology of shunt failure with improved mathematical models, and perhaps animal models of shunt failure. Efficacy of new devices or treatments must be scrutinized scientifically so as not to waste valuable resources and time on unproven treatments. Uncontrolled series and testimonial

  2. A Retrospective Analysis of Ventriculoperitoneal Shunt Revision Cases of a Single Institute

    PubMed Central

    Park, Man-Kyu; Kim, Myungsoo; Park, Ki-Su; Park, Seong-Hyun; Hwang, Jeong-Hyun

    2015-01-01

    Objective Ventriculoperitoneal (VP) shunt complication is a major obstacle in the management of hydrocephalus. To study the differences of VP shunt complications between children and adults, we analyzed shunt revision surgery performed at our hospital during the past 10 years. Methods Patients who had undergone shunt revision surgery from January 2001 to December 2010 were evaluated retrospectively by chart review about age distribution, etiology of hydrocephalus, and causes of revision. Patients were grouped into below and above 20 years old. Results Among 528 cases of VP shunt surgery performed in our hospital over 10 years, 146 (27.7%) were revision surgery. Infection and obstruction were the most common causes of revision. Fifty-one patients were operated on within 1 month after original VP shunt surgery. Thirty-six of 46 infection cases were operated before 6 months after the initial VP shunt. Incidence of shunt catheter fracture was higher in younger patients compared to older. Two of 8 fractured catheters in the younger group were due to calcification and degradation of shunt catheters with fibrous adhesion to surrounding tissue. Conclusion The complications of VP shunts were different between children and adults. The incidence of shunt catheter fracture was higher in younger patients. Degradation of shunt catheter associated with surrounding tissue calcification could be one of the reasons of the difference in facture rates. PMID:26113963

  3. Management for traumatic chronic subdural hematoma patients with well-controlled shunt system for hydrocephalus.

    PubMed

    Yamada, Shoko Mitrrt; Tomia, Yusuke; Murakami, Hideki; Nakane, Makoto

    2015-07-01

    Traumatic CSDH enlarged in two cases with VP or LP shunt system although the shunt valve pressure was increased to 200 mmH2O. In surgery, the hematoma cavity pressure was found to be 130 and 140 mmH2O, suggesting that to raise the shunt valve pressure is not effective for decreasing CSDH volume.

  4. Successful Embolization of a Spontaneous Mesocaval Shunt Using the Amplatzer Vascular Plug II

    SciTech Connect

    Boixadera, Helena; Tomasello, Alejandro; Quiroga, Sergi; Cordoba, Joan; Perez, Mercedes; Segarra, Antoni

    2010-10-15

    A 48-year-old man with alcoholic liver cirrhosis and hepatic encephalopathy was found to have a large, spontaneous mesocaval shunt. The shunt was successfully occluded with the use of an Amplatzer Vascular Plug. To our knowledge, this is the first report of the use of this device to embolize a mesocaval shunt involving the superior mesenteric vein.

  5. Pathogenesis of rhinitis.

    PubMed

    Eifan, A O; Durham, S R

    2016-09-01

    Rhinitis is a heterogeneous condition that has been associated with inflammatory responses as in allergic rhinitis but can also occur in the absence of inflammation such as in so-called idiopathic (previously 'vasomotor') rhinitis. Allergic rhinitis affects approximately one in four of the population of westernized countries and is characterized by typical symptoms of nasal itching, sneezing, watery discharge and congestion. The intention of this review is to illustrate key concepts of the pathogenesis of rhinitis. Imbalance in innate and adaptive immunity together with environmental factors is likely to play major roles. In allergic rhinitis, initial allergen exposure and sensitization involves antigen-presenting cells, T and B lymphocytes and results in the generation of allergen-specific T cells and allergen-specific IgE antibodies. On re-exposure to relevant allergens, cross-linking of IgE on mast cells results in the release of mediators of hypersensitivity such as histamine and immediate nasal symptoms. Within hours, there is an infiltration by inflammatory cells, particularly Th2 T lymphocytes, eosinophils and basophils into nasal mucosal tissue that results in the late-phase allergic response. Evidence for nasal priming and whether or not remodelling may be a feature of allergic rhinitis will be reviewed. The occurrence of so-called local allergic rhinitis in the absence of systemic IgE will be discussed. Non-allergic (non-IgE-mediated) rhinitis will be considered in the context of inflammatory and non-inflammatory disorders. PMID:27434218

  6. Pathogenesis of liver cirrhosis

    PubMed Central

    Zhou, Wen-Ce; Zhang, Quan-Bao; Qiao, Liang

    2014-01-01

    Liver cirrhosis is the final pathological result of various chronic liver diseases, and fibrosis is the precursor of cirrhosis. Many types of cells, cytokines and miRNAs are involved in the initiation and progression of liver fibrosis and cirrhosis. Activation of hepatic stellate cells (HSCs) is a pivotal event in fibrosis. Defenestration and capillarization of liver sinusoidal endothelial cells are major contributing factors to hepatic dysfunction in liver cirrhosis. Activated Kupffer cells destroy hepatocytes and stimulate the activation of HSCs. Repeated cycles of apoptosis and regeneration of hepatocytes contribute to pathogenesis of cirrhosis. At the molecular level, many cytokines are involved in mediation of signaling pathways that regulate activation of HSCs and fibrogenesis. Recently, miRNAs as a post-transcriptional regulator have been found to play a key role in fibrosis and cirrhosis. Robust animal models of liver fibrosis and cirrhosis, as well as the recently identified critical cellular and molecular factors involved in the development of liver fibrosis and cirrhosis will facilitate the development of more effective therapeutic approaches for these conditions. PMID:24966602

  7. Pathogenesis of Nonalcoholic Steatohepatitis.

    PubMed

    Machado, Mariana Verdelho; Diehl, Anna Mae

    2016-06-01

    Nonalcoholic steatohepatitis (NASH) is a necro-inflammatory response that ensues when hepatocytes are injured by lipids (lipotoxicity). NASH is a potential outcome of nonalcoholic fatty liver (NAFL), a condition that occurs when lipids accumulate in hepatocytes. NASH may be reversible, but it can also result in cirrhosis and primary liver cancer. We are beginning to learn about the mechanisms of progression of NAFL and NASH. NAFL does not inevitably lead to NASH because NAFL is a heterogeneous condition. This heterogeneity exists because different types of lipids with different cytotoxic potential accumulate in the NAFL, and individuals with NAFL differ in their ability to defend against lipotoxicity. There are no tests that reliably predict which patients with NAFL will develop lipotoxicity. However, NASH encompasses the spectrum of wound-healing responses induced by lipotoxic hepatocytes. Differences in these wound-healing responses among individuals determine whether lipotoxic livers regenerate, leading to stabilization or resolution of NASH, or develop progressive scarring, cirrhosis, and possibly liver cancer. We review concepts that are central to the pathogenesis of NASH.

  8. Staphylococcus epidermidis pathogenesis.

    PubMed

    Otto, Michael

    2014-01-01

    Staphylococcus epidermidis is the most frequently encountered member of the coagulase-negative staphylococci on human epithelial surfaces. It has emerged as an important nosocomial pathogen, especially in infections of indwelling medical devices. The mechanisms that S. epidermidis uses to survive during infection are in general of a passive nature, reflecting their possible origin in the commensal life of this bacterium. Most importantly, S. epidermidis excels in forming biofilms, sticky agglomerations that inhibit major host defense mechanisms. Furthermore, S. epidermidis produces a series of protective surface polymers and exoenzymes. Moreover, S. epidermidis has the capacity to secrete strongly cytolytic members of the phenol-soluble modulin (PSM) family, but PSMs in S. epidermidis overall appear to participate primarily in biofilm development. Finally, there is evidence for a virulence gene reservoir function of S. epidermidis, as it appears to have transferred important immune evasion and antibiotic resistance factors to Staphylococcus aureus. Conversely, S. epidermidis also has a beneficial role in balancing the microflora on human epithelial surfaces by controlling outgrowth of harmful bacteria such as in particular S. aureus. Recent research yielded detailed insight into key S. epidermidis virulence determinants and their regulation, in particular as far as biofilm formation is concerned, but we still have a serious lack of understanding of the in vivo relevance of many pathogenesis mechanisms and the factors that govern the commensal life of S. epidermidis.

  9. Pathogenesis of liver cirrhosis.

    PubMed

    Zhou, Wen-Ce; Zhang, Quan-Bao; Qiao, Liang

    2014-06-21

    Liver cirrhosis is the final pathological result of various chronic liver diseases, and fibrosis is the precursor of cirrhosis. Many types of cells, cytokines and miRNAs are involved in the initiation and progression of liver fibrosis and cirrhosis. Activation of hepatic stellate cells (HSCs) is a pivotal event in fibrosis. Defenestration and capillarization of liver sinusoidal endothelial cells are major contributing factors to hepatic dysfunction in liver cirrhosis. Activated Kupffer cells destroy hepatocytes and stimulate the activation of HSCs. Repeated cycles of apoptosis and regeneration of hepatocytes contribute to pathogenesis of cirrhosis. At the molecular level, many cytokines are involved in mediation of signaling pathways that regulate activation of HSCs and fibrogenesis. Recently, miRNAs as a post-transcriptional regulator have been found to play a key role in fibrosis and cirrhosis. Robust animal models of liver fibrosis and cirrhosis, as well as the recently identified critical cellular and molecular factors involved in the development of liver fibrosis and cirrhosis will facilitate the development of more effective therapeutic approaches for these conditions.

  10. Pathogenesis of Mucormycosis

    PubMed Central

    Spellberg, Brad; Walsh, Thomas J.; Kontoyiannis, Dimitrios P.

    2012-01-01

    Mucormycosis is a life-threatening infection that occurs in patients who are immunocompromised because of diabetic ketoacidosis, neutropenia, organ transplantation, and/or increased serum levels of available iron. Because of the increasing prevalence of diabetes mellitus, cancer, and organ transplantation, the number of patients at risk for this deadly infection is increasing. Despite aggressive therapy, which includes disfiguring surgical debridement and frequently adjunctive toxic antifungal therapy, the overall mortality rate is high. New strategies to prevent and treat mucormycosis are urgently needed. Understanding the pathogenesis of mucormycosis and the host response to invading hyphae ultimately will provide targets for novel therapeutic interventions. In this supplement, we review the current knowledge about the virulence traits used by the most common etiologic agent of mucormycosis, Rhizopus oryzae. Because patients with elevated serum levels of available iron are uniquely susceptible to mucormycosis and these infections are highly angioinvasive, emphasis is placed on the ability of the organism to acquire iron from the host and on its interactions with endothelial cells lining blood vessels. Several promising therapeutic strategies in preclinical stages are identified. PMID:22247441

  11. Recent progress in melasma pathogenesis.

    PubMed

    Lee, Ai-Young

    2015-11-01

    Melasma is a common skin pigmentation condition. Given therapeutic difficulty as one of the biggest concerns, understanding of the etiology and pathogenesis of melasma becomes essential. UV irradiation, female sex hormones, and inflammatory processes are addressed as triggering factors with genetic predisposition. The mechanism of UV-induced melanogenesis has been extensively investigated as a model system to study melasma pathogenesis. Hitherto, treatment modalities for melasma are similar to other hyperpigmentation disorders. However, individual triggering factors induce a separate pigmentation disease, whose pathogenic mechanisms and clinical phenotypes are different from the ones encountered in melasma. Fortunately, there have been ongoing updates on melasma pathogenesis with regard to major triggering factors. Presence of certain factors working independently of UV exposure and role of dermal factors and microRNAs are being identified as novel discoveries about melasma pathogenesis. In this review, the melasma pathogenesis is reviewed in association with updated and new findings.

  12. High-Flow Arterio-Hepatic Venous Shunt in Hepatocellular Carcinoma: Use of Multi-Electrode Radiofrequency for Shunt Obliteration

    SciTech Connect

    Pua, Uei

    2015-10-15

    Intra-tumoral arterio-hepatic venous shunting (AHVS) poses an impediment to transarterial chemoembolization of liver tumors. Not only does it present a potential hazard for systemic shunting and embolization, but also the altered flow dynamics may also result in poor delivery of drug/embolics to the target tumor bed. Current available techniques to overcome AVHS include arterial embolization (particles, coils, glue, etc.) or temporary venous occlusion using balloons. We hereby illustrate the use of radiofrequency ablation to obliterate a complex AHVS consisting of a varix-like venous aneurysm.

  13. Risk factors for shunt malfunction in pediatric hydrocephalus: a multicenter prospective cohort study.

    PubMed

    Riva-Cambrin, Jay; Kestle, John R W; Holubkov, Richard; Butler, Jerry; Kulkarni, Abhaya V; Drake, James; Whitehead, William E; Wellons, John C; Shannon, Chevis N; Tamber, Mandeep S; Limbrick, David D; Rozzelle, Curtis; Browd, Samuel R; Simon, Tamara D

    2016-04-01

    OBJECT The rate of CSF shunt failure remains unacceptably high. The Hydrocephalus Clinical Research Network (HCRN) conducted a comprehensive prospective observational study of hydrocephalus management, the aim of which was to isolate specific risk factors for shunt failure. METHODS The study followed all first-time shunt insertions in children younger than 19 years at 6 HCRN centers. The HCRN Investigator Committee selected, a priori, 21 variables to be examined, including clinical, radiographic, and shunt design variables. Shunt failure was defined as shunt revision, subsequent endoscopic third ventriculostomy, or shunt infection. Important a priori-defined risk factors as well as those significant in univariate analyses were then tested for independence using multivariate Cox proportional hazard modeling. RESULTS A total of 1036 children underwent initial CSF shunt placement between April 2008 and December 2011. Of these, 344 patients experienced shunt failure, including 265 malfunctions and 79 infections. The mean and median length of follow-up for the entire cohort was 400 days and 264 days, respectively. The Cox model found that age younger than 6 months at first shunt placement (HR 1.6 [95% CI 1.1-2.1]), a cardiac comorbidity (HR 1.4 [95% CI 1.0-2.1]), and endoscopic placement (HR 1.9 [95% CI 1.2-2.9]) were independently associated with reduced shunt survival. The following had no independent associations with shunt survival: etiology, payer, center, valve design, valve programmability, the use of ultrasound or stereotactic guidance, and surgeon experience and volume. CONCLUSIONS This is the largest prospective study reported on children with CSF shunts for hydrocephalus. It confirms that a young age and the use of the endoscope are risk factors for first shunt failure and that valve type has no impact. A new risk factor-an existing cardiac comorbidity-was also associated with shunt failure.

  14. Complications and subsequent removal of retained shunt hardware after endoscopic third ventriculostomy: case series.

    PubMed

    Pindrik, Jonathan; Jallo, George I; Ahn, Edward S

    2013-06-01

    This case series highlights multiple complications and subsequent removal of retained shunt hardware in pediatric patients after successful endoscopic third ventriculostomy (ETV). Removal or retention of existing shunt hardware following ETV represents an important dilemma. Prior studies have reported infections and organ perforation related to nonfunctioning shunts but none in the context of successful ETV. Data obtained in 3 children with hydrocephalus treated at the authors' institution were retrospectively reviewed after the patients experienced complications due to retained shunt hardware following ETV. Etiologies of hydrocephalus included tectal glioma and intraventricular hemorrhage. All 3 patients had a history of multiple shunt revisions and underwent urgent ETV in the setting of a shunt malfunction. In each case, the entire shunt system was left in situ, but it became the source of subsequent complications. Two of the 3 patients presented with the shunt infected by gram-negative bacilli 10 days and 4.5 months postoperatively, respectively. The remaining patient experienced wound dehiscence over the shunt valve 4.5 months after ETV. In all patients, the complications were managed successfully by removing the shunt hardware. None of the patients required repeat shunt insertion from the time of removal throughout the follow-up period (mean 24 months, range 9-36 months). During the study period, a total of 6 patients with indwelling shunt hardware underwent ETV with the expectation of being shunt independent. Among these 6 patients, 3 experienced no complications from the retained hardware whereas 3 patients (50%) ultimately experienced adverse consequences related to retained hardware. This case series illustrates complications involving retained shunt hardware after successful ETV. These examples support consideration of shunt removal at the time of ETV in the appropriate context.

  15. Pathogenesis of bovine neosporosis.

    PubMed

    Dubey, J P; Buxton, D; Wouda, W

    2006-05-01

    The protozoan parasite Neospora caninum is a major pathogen of cattle and dogs, being a significant cause of abortion in cattle in many countries. It is one of the most efficiently transmitted parasites, with up to 90% of cattle infected in some herds. The pathogenesis of abortion due to Neospora is complex and only partially understood. Losses occur after a primary infection during pregnancy but more commonly as the result of recrudescence of a persistent infection during pregnancy. Parasitaemia is followed by invasion of the placenta and fetus. It is suggested that abortion occurs when primary parasite-induced placental damage jeopardises fetal survival directly or causes release of maternal prostaglandins that in turn cause luteolysis and abortion. Fetal damage may also occur due to primary tissue damage caused by the multiplication of N. caninum in the fetus or due to insufficient oxygen/nutrition, secondary to placental damage. In addition, maternal immune expulsion of the fetus may occur associated with maternal placental inflammation and the release of maternal pro-inflammatory cytokines in the placenta. Thus N. caninum is a primary pathogen capable of causing abortion either through maternal placental inflammation, maternal and fetal placental necrosis, fetal damage, or a combination of all three. The question of how N. caninum kills the fetus exposes the complex and finely balanced biological processes that have evolved to permit bovine and other mammalian pregnancies to occur. Defining these immunological mechanisms will shed light on potential methods of control of bovine neosporosis and enrich our understanding of the continuity of mammalian and protozoal survival. PMID:16712863

  16. Comparison of passive inductor designs for piezoelectric shunt damping

    NASA Astrophysics Data System (ADS)

    Lossouarn, Boris; Thierry, Olivier; Aucejo, Mathieu; Deü, Jean-François

    2016-04-01

    Considering piezoelectric damping, a resonant shunt can lead to a significant vibration reduction when tuned to the mechanical mode to control. However, limits appear when looking at practical applications in a low frequency range: the required inductance is often too high to be satisfied with standard passive components. Moreover, even if the inductor is eventually available, the internal resistance of the component generally exceeds the value which is required for a shunt optimization. Suitable inductors can be designed for applications requiring high inductance and low resistance values. Indeed, the permeance of a magnetic circuit can be significantly increased by the use of closed cores made of high permeability materials. In this paper, three designs are described and compared: an inductor from standard series and two handmade inductors involving a ferrite core and a nanocrystalline toroid. The components are successively integrated into a piezoelectric shunt dedicated to the vibration control of a cantilever beam. Depending on the frequency of the target mechanical mode to control, the benefits and the limits of the different inductors are observed. It is shown that custom designs can definitely extend to lower frequency the application of the passive resonant shunt strategy.

  17. CONTEXT VIEW ALONG EXISTING PERIMETER TRACKS LOOKING TOWARDS SHUNTS IN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    CONTEXT VIEW ALONG EXISTING PERIMETER TRACKS LOOKING TOWARDS SHUNTS IN THEIR PRESENT-DAY POSITIONS, STORAGE SHED, AND MACHINE SHOP. LOOKING NORTHEAST. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

  18. Shunt impedance measurement of the APS BBC injector.

    SciTech Connect

    Sun, Y.-E.; Lewellen, J. W.

    2006-01-01

    The injector test stand (ITS) at Advanced Photon Source (APS) presently incorporates a ballistic bunch compression (BBC) gun, and it is used as a beam source for a number of experiments, including THz generation, beam position monitor testing for the Linac Coherent Light Source (LCLS), novel cathode testing, and radiation therapy source development. The BBC gun uses three independently powered and phased rf cavities, one cathode cell, and two full cells to provide beam energies from 2 to 10 MeV with variable energy spread, energy chirp, and, to an extent, bunch duration. The shunt impedance of an rf accelerator determines how effectively the accelerator can convert supplied rf power to accelerating gradient. The calculation of the shunt impedance can be complicated if the beam energy changes substantially during its transit through a cavity, such as in a cathode cell. We present the results of direct measurements of the shunt impedance of the APS BBC gun on an individual cavity basis, including the cathode cell, and report on achieved gradients. We also present a comparison of the measured shunt impedance with theoretical values calculated from the rf models of the cavities.

  19. Ascites-induced LeVeen shunt coagulopathy.

    PubMed Central

    Ragni, M V; Lewis, J H; Spero, J A

    1983-01-01

    Ten of 11 patients undergoing peritoneovenous (LeVeen) shunt placement for intractable ascites had disseminated intravascular coagulation (DIC) following the shunt procedure. Intraoperative ascitic fluid specimens revealed fibrin split products (FSP) in high titer (1:100-1:1600) in all patients. Endotoxin was found in 6 of 11 ascitic fluid samples but in no plasma samples. Activated clotting factors, clot inhibitors, excess protein, and fibrinolytic activity were not found in ascitic fluid. Clotting factor levels were much lower than in plasma. Bleeding occurred after operation in two patients; this appeared to be related to the severity of liver dysfunction as demonstrated by elevations of bilirubin, serum glutamic oxalocetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), and preoperative DIC. It is concluded that the LeVeen shunt coagulopathy is DIC, and may be related to exposure of the systemic circulation to FSP-rich ascitic fluid that may activate the coagulation mechanism. Bleeding complications do not appear to be related to the severity of the post shunt coagulopathy, but rather to the severity of liver dysfunction and presence of preoperative DIC (probably caused by the liver disease). PMID:6859998

  20. Constipation as a reversible cause of ventriculoperitoneal shunt failure. Report of two cases.

    PubMed

    Powers, Ciaran J; George, Timothy; Fuchs, Herbert E

    2006-09-01

    Ventriculoperitoneal (VP) shunt failure is a common problem encountered by pediatric neurosurgeons. The majority of such failures are due to obstruction of the device. Conditions in which intraabdominal pressure is chronically elevated, such as pregnancy, have been associated with shunt failure. Chronic constipation may also result in abnormally elevated intraabdominal pressure and may be an underrecognized cause of distal VP shunt failure. The authors describe the cases of two children who presented with clinical and imaging evidence of VP shunt failure and who were also severely constipated. Treatment of their constipation resulted in both clinical and imaging-documented resolution of their shunt failure.

  1. Inferior vena cava stent grafting closure of a high-flow portacaval shunt.

    PubMed

    Alhaizaey, Abdullah; Ghanekar, Anand; Oreopoulos, George

    2016-01-01

    Portacaval (PC) shunts can be of congenital or acquired types. Acquired PC shunts are usually created in patients with end-stage liver disease to manage complications associated with portal hypertension or may be part of selected adult-adult living donor liver transplantation procedures to decrease the chance of the small-for-size syndrome. The main potential complication of these acquired high-flow PC shunts is early hepatic encephalopathy. We present a case of a high-flow acquired PC shunt after liver transplantation that was complicated by uncontrolled encephalopathy. This was treated by endovascular inferior vena cava stent grafting for shunt closure. PMID:26946901

  2. Control of an electromechanical hydrocephalus shunt--a new approach.

    PubMed

    Elixmann, Inga M; Kwiecien, Monika; Goffin, Christine; Walter, Marian; Misgeld, Berno; Kiefer, Michael; Steudel, Wolf-Ingo; Radermacher, Klaus; Leonhardt, Steffen

    2014-09-01

    Hydrocephalus is characterized by an excessive accumulation of cerebrospinal fluid (CSF). Therapeutically, an artificial pressure relief valve (so-called shunt) is implanted which opens in case of increased intracranial pressure (ICP) and drains CSF into another body compartment. Today, available shunts are of a mechanical nature and drainage depends on the pressure drop across the shunt. According to the latest data, craniospinal compliance is considered to be even more important than mean ICP alone. In addition, ICP is not constant but varies due to several influences. In fact, heartbeat-related ICP waveform patterns depend on volume changes in the cranial vessels during a heartbeat and changes its shape as a function of craniospinal compliance. In this paper, we present an electromechanical shunt approach, which changes the CSF drainage as a function of the current ICP waveform. A series of 12 infusion tests in patients were analyzed and revealed a trend between the compliance and specific features of the ICP waveform. For waveform analysis of patient data, an existing signal processing algorithm was improved (using a Moore machine) and was implemented on a low-power microcontroller within the electromechanical shunt. In a test rig, the ICP waveforms were replicated and the decisions of the ICP analysis algorithm were verified. The proposed control algorithm consists of a cascaded integral controller which determines the target ICP from the measured waveform, and a faster inner-loop integral controller that keeps ICP close to the target pressure. Feedforward control using measurement data of the patient's position was implemented to compensate for changes in hydrostatic pressure during change in position. A model-based design procedure was used to lay out controller parameters in a simple model of the cerebrospinal system. Successful simulation results have been obtained with this new approach by keeping ICP within the target range for a healthy waveform.

  3. Experimental comparison of piezoelectric and magnetostrictive shunt dampers

    NASA Astrophysics Data System (ADS)

    Asnani, Vivake M.; Deng, Zhangxian; Scheidler, Justin J.; Dapino, Marcelo J.

    2016-04-01

    A novel mechanism called the vibration ring is being developed to enable energy conversion elements to be incorporated into the driveline of a helicopter or other rotating machines. Unwanted vibration is transduced into electrical energy, which provides a damping effect on the driveline. The generated electrical energy may also be used to power other devices (e.g., health monitoring sensors). PZT (`piezoceramic') and PMN-30%PT (`single crystal') stacks, as well as a Tb0.3Dy0.7Fe1.92 (`Terfenol-D') rod with a bias magnet array and a pickup coil, were tested as alternative energy conversion elements to use within the vibration ring. They were tuned for broadband damping using shunt resistors, and dynamic compression testing was conducted in a high-speed load frame. Energy conversion was experimentally optimized at 750Hz by tuning the applied bias stress and resistance values. Dynamic testing was conducted up to 1000Hz to determine the effective compressive modulus, shunt loss factor, internal loss factor, and total loss factor. Some of the trends of modulus and internal loss factor versus frequency were unexplained. The single crystal device exhibited the greatest shunt loss factor whereas the Terfenol-D device had the highest internal and total loss factors. Simulations revealed that internal losses in the Terfenol-D device were elevated by eddy current effects, and an improved magnetic circuit could enhance its shunt damping capabilities. Alternatively, the Terfenol-D device may be simplified to utilize only the eddy current dissipation mechanism (no pickup coil or shunt) to create broadband damping.

  4. Cerebrospinal fluid shunt infections. A review of 35 infections in 32 patients.

    PubMed

    Forward, K R; Fewer, H D; Stiver, H G

    1983-09-01

    The authors have reviewed the clinical manifestations and therapy of hydrocephalus shunt infections in 32 patients with a total of 35 shunt infections. These 35 infections accounted for 43 hospital admissions. First infections usually developed within 2 months following surgery. At the time of diagnosis, 89% of patients were febrile. Fever and cough as a symptom complex characterized the initial clinical presentation in six of 19 episodes of infection complicating ventriculoatrial (VA) shunts, as compared with none of 21 episodes in which infection complicated ventriculoperitoneal (VP) shunts. Seven of 21 infectious episodes occurring in patients with VP shunts in situ were associated with significant abdominal pain and tenderness. These patients usually had no other clinical features to suggest shunt infection. Both of these symptom complexes often led to delays in diagnosis and treatment. Causative organisms included Staphylococcus epidermidis in 21, Staphylococcus aureus in seven, Gram-negative aerobic bacilli in seven, diphtheroids in five, Streptococcus species in four, and anaerobes in three. Five infections were polymicrobial in nature. Positive blood cultures were seen in 13 of 17 infectious episodes complicating VA shunts, as compared with only three of 13 other infections. When the shunt was completely removed, with or without replacement, all 13 patients were cured. When intravenous antibiotics were administered in conjunction with incomplete shunt removal, only eight of 15 courses resulted in cure. Intraventricular antibiotics were administered in four patients and all were cured. Therapy of shunt infections with parenteral antibiotics and incomplete shunt removal is associated with an unacceptably high failure rate.

  5. Risk factors associated with distal catheter migration following ventriculoperitoneal shunt placement.

    PubMed

    Abode-Iyamah, Kingsley O; Khanna, Ryan; Rasmussen, Zachary D; Flouty, Oliver; Dahdaleh, Nader S; Greenlee, Jeremy; Howard, Matthew A

    2016-03-01

    Ventriculoperitoneal (VP) shunt placement is used to treat hydrocephalus. Shunt migration following VP shunt placement has been reported. The risk factors related to this complication have not been previously evaluated to our knowledge. In this retrospective cohort study, we aimed to determine risk factors leading to distal catheter migration and review the literature on the current methods of management and prevention. Adult patients undergoing VP shunt placement from June 2011 to December 2013 at a single institution were identified using electronic health records. The records were reviewed for demographic and procedural information, and subsequent treatment characteristics. The parameters of patients with distal shunt migration were compared to those undergoing new VP shunt placement for the same time period. We identified 137 patients undergoing 157 new VP shunt procedures with an average age of 57.7 ± standard deviation of 18.4 years old. There were 16 distal shunt migrations. Body mass index >30 kg/m(2) and number of previous shunt procedures were found to be independent risk factors for distal catheter migration. Obesity and number of previous shunt procedures were factors for distal catheter migration. Providers and patients should be aware of these possible risk factors prior to VP shunt placement.

  6. New and improved ways to treat hydrocephalus: Pursuit of a smart shunt

    PubMed Central

    Lutz, Barry R.; Venkataraman, Pranav; Browd, Samuel R.

    2013-01-01

    The most common treatment for hydrocephalus is placement of a cerebrospinal fluid shunt to supplement or replace lost drainage capacity. Shunts are life-saving devices but are notorious for high failure rates, difficulty of diagnosing failure, and limited control options. Shunt designs have changed little since their introduction in 1950s, and the few changes introduced have had little to no impact on these long-standing problems. For decades, the community has envisioned a “smart shunt” that could provide advanced control, diagnostics, and communication based on implanted sensors, feedback control, and telemetry. The most emphasized contribution of smart shunts is the potential for advanced control algorithms, such as weaning from shunt dependency and personalized control. With sensor-based control comes the opportunity to provide data to the physician on patient condition and shunt function, perhaps even by a smart phone. An often ignored but highly valuable contribution would be designs that correct the high failure rates of existing shunts. Despite the long history and increasing development activity in the past decade, patients are yet to see a commercialized smart shunt. Most smart shunt development focuses on concepts or on isolated technical features, but successful smart shunt designs will be a balance between technical feasibility, economic viability, and acceptable regulatory risk. Here, we present the status of this effort and a framework for understanding the challenges and opportunities that will guide introduction of smart shunts into patient care. PMID:23653889

  7. Role of SEP in identifying patients requiring temporary shunt during carotid endarterectomy.

    PubMed

    Fava, E; Bortolani, E; Ducati, A; Schieppati, M

    1992-01-01

    EEGs and short-latency somatosensory evoked potentials (SEPs) to median nerve stimulation were recorded during 151 carotid endarterectomies, performed under general anaesthesia. Carotid occlusion did not affect either EEG or SEP in 120 cases (group A). In 31 cases the EEG showed "ischaemic" abnormalities (group B). A temporary shunt was inserted only in 16 B patients showing also severely depressed cortical SEPs within 2 min after carotid occlusion (group B shunt). In 15 B patients in whom SEPs were less affected, the operation was completed without shunt (group B no shunt). One intraoperative stroke occurred in group A and two in group B shunt. No neurological complications occurred in group B no shunt. Overall stroke rate was 2%. On retrospective analysis, latency and amplitude of N20 and P25 waves proved to be uninfluenced by carotid occlusion in group A, but were significantly affected in group B shunt. P25 amplitude alone was reduced in B no shunt. An arbitrary index (need-for-shunt index, NSI) was made in order to rate changes of P25 latency and amplitude. Its mean values were significantly different in the 3 groups. A threshold value is suggested above which shunt is required, as a useful adjunct to EEG, in order to balance prevention of brain ischaemia against the risks of shunt.

  8. Pathogenesis of Acanthamoeba Keratitis

    PubMed Central

    Panjwani, Noorjahan

    2010-01-01

    Acanthamoeba keratitis (AK) is a serious infection of the cornea. At present, diagnosis of the disease is not straightforward and treatment is very demanding. While contact lens wear is the leading risk factor for AK, Acanthamoeba parasites are increasingly recognized as an important cause of keratitis in non-contact lens wearers. The first critical step in the pathogenesis of infection is the adhesion of the microbe to the surface of the host tissues. Acanthamoebae express a major virulence protein, the mannose-binding protein (MBP), which mediates the adhesion of amoebae to the surface of the cornea. The MBP is a transmembrane protein with characteristics of a typical cell surface receptor. Subsequent to the MBP-mediated adhesion to host cells, the amoebae produce a contact-dependent metalloproteinase and several contact-independent serine proteinases. These proteinases work in concert to produce a potent cytopathic effect (CPE) involving killing of the host cells, degradation of epithelial basement membrane and underlying stromal matrix, and penetration into the deeper layers of the cornea. In the hamster animal model, oral immunization with the recombinant MBP protects against AK, and this protection is associated with an increased level of anti-MBP IgA in tears of protected animals. Normal human tear fluid contains IgA antibodies against Acanthamoeba MBP that is likely to provide protection by inhibiting the adhesion of parasites to host cells. Indeed, in in vitro CPE assays, even a low concentration of tears (10 [MU]μL of undiluted tears per milliliter of media) almost completely inhibits Acanthamoeba-induced CPE. In addition to adherence-inhibiting, IgA-mediated protection, human tears also contain IgA-independent factors that provide protection against Acanthamoeba-induced CPE by inhibiting the activity of cytotoxic proteinases. Characterization of the CPE-inhibitory factors of human tears should lead to a better understanding of the mechanism by which the

  9. Fuzzy Inference System Approach for Locating Series, Shunt, and Simultaneous Series-Shunt Faults in Double Circuit Transmission Lines.

    PubMed

    Swetapadma, Aleena; Yadav, Anamika

    2015-01-01

    Many schemes are reported for shunt fault location estimation, but fault location estimation of series or open conductor faults has not been dealt with so far. The existing numerical relays only detect the open conductor (series) fault and give the indication of the faulty phase(s), but they are unable to locate the series fault. The repair crew needs to patrol the complete line to find the location of series fault. In this paper fuzzy based fault detection/classification and location schemes in time domain are proposed for both series faults, shunt faults, and simultaneous series and shunt faults. The fault simulation studies and fault location algorithm have been developed using Matlab/Simulink. Synchronized phasors of voltage and current signals of both the ends of the line have been used as input to the proposed fuzzy based fault location scheme. Percentage of error in location of series fault is within 1% and shunt fault is 5% for all the tested fault cases. Validation of percentage of error in location estimation is done using Chi square test with both 1% and 5% level of significance.

  10. Fuzzy Inference System Approach for Locating Series, Shunt, and Simultaneous Series-Shunt Faults in Double Circuit Transmission Lines

    PubMed Central

    Swetapadma, Aleena; Yadav, Anamika

    2015-01-01

    Many schemes are reported for shunt fault location estimation, but fault location estimation of series or open conductor faults has not been dealt with so far. The existing numerical relays only detect the open conductor (series) fault and give the indication of the faulty phase(s), but they are unable to locate the series fault. The repair crew needs to patrol the complete line to find the location of series fault. In this paper fuzzy based fault detection/classification and location schemes in time domain are proposed for both series faults, shunt faults, and simultaneous series and shunt faults. The fault simulation studies and fault location algorithm have been developed using Matlab/Simulink. Synchronized phasors of voltage and current signals of both the ends of the line have been used as input to the proposed fuzzy based fault location scheme. Percentage of error in location of series fault is within 1% and shunt fault is 5% for all the tested fault cases. Validation of percentage of error in location estimation is done using Chi square test with both 1% and 5% level of significance. PMID:26413088

  11. Peritoneovenous Shunt Insertion for Intractable Ascites-A District General Hospital Experience

    SciTech Connect

    Hussain, Fuad F. Meer, Ziad F.; Lopez, Anthony J.

    2004-08-15

    Ascites often contributes to patient morbidity and discomfort. When refractory to medical management, it has been managed with repeated paracentesis, implantable ports for drainage, or diversion to the urinary bladder. Peritoneovenous shunt insertion has been a technique that was traditionally performed only by surgeons but is now within the realm of interventional radiologists. Its advantage is that protein-rich ascitic fluid is returned to the intravascular compartment. This retrospective study elaborates on the successes and problems encountered during shunt insertion in our first 13 patients. Two patients are well with a functioning shunt at 14 and 32 weeks. In 6 the shunt functioned until the patients' death from the underlying malignancy. Two required revision with variable success and in 2, shunt function could not be salvaged. There was one procedure-related mortality. Radiological insertion of these shunts is feasible and should be considered for selected patients. Options are available for assessment and salvaging of dysfunctional shunts.

  12. Ventriculoperitoneal Shunt Complications In Children: An Evidence-Based Approach To Emergency Department Management.

    PubMed

    Bober, Jacqueline; Rochlin, Jonathan; Marneni, Shashidhar

    2016-02-01

    Although much is known about ventriculoperitoneal shunts, there are still large gaps in the literature and no evidence-based guidelines on management. To date, there is no general consensus on workup and treatment, and there are many differing diagnostic and therapeutic strategies for management of complications. Ventriculoperitoneal shunt complications can be separated into 3 categories: mechanical failure, infection, and functional failure. Knowing the basic anatomy of ventriculoperitoneal shunts, the time of shunt placement, and the clinical manifestations suggestive of potential complications can help with the management of patients with ventriculoperitoneal shunts. This review summarizes the literature on complications of ventriculoperitoneal shunts, examines the literature regarding the workup and management of patients with ventriculoperitoneal shunts, and makes recommendations for the management of these patients in the emergency department.

  13. Lumboatrial shunt in a patient with Crouzon syndrome complicated by pseudotumor cerebri.

    PubMed

    Sankey, Eric W; Khattab, Mohamed H; Elder, Benjamin D; Goodwin, C Rory; Rekate, Harold L; Rigamonti, Daniele

    2015-09-01

    A 25-year-old man with Crouzon syndrome complicated by pseudotumor cerebri and multiple shunt failures presented with progressive back and neck pain, intermittent headaches, and associated vomiting secondary to shunt infection. Due to his previous history of repeated failure of both ventriculoperitoneal and lumboperitoneal (LP) shunting procedures, the decision was made to place a lumboatrial (LA) shunt via an approach through the internal jugular vein. The procedure was uncomplicated and the man's symptoms were relieved. Despite significant improvement, the LA shunt limited his exercise tolerance, and as an avid runner and weight lifter, he requested reconversion back to an LP shunt. At a follow-up of 20months, he continued to do well both clinically and radiographically. This case report summarizes the successful placement and use of an LA shunt for the treatment of intracranial hypertension in the setting of Crouzon syndrome. PMID:26021731

  14. Systemic-pulmonary artery shunts in infants: modified Blalock-Taussig and central shunt procedures.

    PubMed

    Brooks, Andre

    2014-01-01

    Access is gained through a midline sternotomy, the thymus partially excised and the superior part of the pericardium is opened. The innominate vein is retracted and the innominate artery is mobilized up to the bifurcation. The aorta is retracted to the left, the superior vena cavae to the right and the right atrial appendage inferiorly. The adventitia around the right pulmonary artery (PA) is dissected, taking care to incise the bulky pericardial reflection between the superior vena cavae and the trachea. Heparin is administrated. An occlusive clamp is applied to the right PA to test for haemodynamic tolerance prior to proceeding with the interposition of a suitable size artificial vascular prosthesis, based on the weight of the patient, between the innominate artery, or proximal subclavian artery and the right PA. Alternatively, if a sufficient main PA is present and adequate flow from a patent ductus arteriosus an end-to-side interposition shunt may be constructed between the ascending aorta and the main PA, provided the patient is stable with the test occlusion of the main PA. The management of the patent arterial ductus depends on whether or not there is forward flow through the PA.

  15. Highlights in pathogenesis of vitiligo

    PubMed Central

    Mohammed, Ghada F; Gomaa, Amal HA; Al-Dhubaibi, Mohammed Saleh

    2015-01-01

    Vitiligo is a common pigmentary disorder. Many studies across decades and all over the world have attempted to illustrate the pathogenesis behind it; however, the pathogenesis of vitiligo remains elusive. This review article, we present the findings behind the most and updated theories behind this psychologically debilitating and disfiguring disease. The discussion begun with the role of genetic predisposition followed by neural theory first proposed in the 1950s. We highlight the autoimmune hypothesis, followed by the reactive oxygen species model, zinc-α2-glycoprotein deficiency hypothesis, viral theory, intrinsic theory and biochemical, molecular and cellular alterations accounting for loss of functioning melanocytes in vitiligo. Many theories were elaborated to clarify vitiligo pathogenesis. It is a multifactorial disease involving the interplay of several factors. Future research is needed to clarify the interaction of these factors for better understanding of vitiligo pathogenesis and subsequent successful treatment. PMID:25789295

  16. Listeria monocytogenes: a rare complication of ventriculoperitoneal shunt in children.

    PubMed

    Le Monnier, Alban; Blanot, Stéphane; Abachin, Eric; Beretti, Jean-Luc; Berche, Patrick; Kayal, Samer

    2011-11-01

    We report a case of ventriculoperitoneal (VP) shunt infection in a 3-year-old boy caused by the food-borne pathogen Listeria monocytogenes, subsequent to acute peritonitis. This unusual presentation of central nervous system (CNS) listeriosis underlines the ability of the bacteria to form and survive within biofilms on indwelling medical devices. Bacterial persistence may lead to treatment failure and spreading. We highlight the helpfulness of specific quantitative real-time PCR for the hly gene (PCR-hly) for the diagnosis and follow-up of such infections in detecting bacterial persistence within medical devices despite effective antibiotic treatment. Only the surgical replacement of the VP shunt will resolve the infection.

  17. Growth of basilar artery aneurysm after ventriculo-peritoneal shunt.

    PubMed

    Kim, Myoung Soo; Oh, Chang-Wan; Han, Dae Hee

    2002-11-01

    We report upon two cases of obstructive hydrocephalus produced by giant basilar artery aneurysms. They initially presented with symptoms of increased intracranial pressure, and were managed by a ventriculo-peritoneal (VP) shunt with good symptomatic improvement. With time, however, both showed a gradual deterioration of clinical symptoms due to increased aneurysm size. One, with a basilar tip aneurysm was treated by direct neck-clipping of the aneurysm, and was able to return to work. In the other patient, with a basilar trunk aneurysm, endovascular occlusion of one vertebral artery was attempted in an effort to decrease the aneurysm size, but the aneurysm enlarged precipitating brain stem failure. In conclusion, these cases reveal the risk of the VP shunt, which may induce aneurysmal growth, leading to clinical devastation, and emphasize the importance of definitive treatment for giant cerebral aneurysms whenever possible.

  18. Protein adsorption to hydrocephalus shunt catheters: CSF protein adsorption

    PubMed Central

    Brydon, H.; Keir, G.; Thompson, E.; Bayston, R.; Hayward, R.; Harkness, W.

    1998-01-01

    OBJECTIVE—To assess the quantity and nature of the proteins that adsorb to hydrocephalus shunt catheters after implantation, and to determine whether sufficient could accumulate to obstruct the catheter.
DESIGN—Elution of proteins from 102 explanted shunt catheters, with protein assay and electrophoresis of the eluate, and scanning electron microscopy (SEM) of the catheters.
RESULTS—The amount of protein elutable was extremely low, and significant protein, apart from a thin film, was not found on SEM. Qualitative analysis disclosed that most of the adsorbed protein was albumin.
CONCLUSIONS—Protein deposition on hydrocephalus catheters does not occur in sufficient quantities to cause catheter obstruction.

 PMID:9598681

  19. Anal extrusion of a ventriculo peritoneal shunt tube: Endoscopic removal.

    PubMed

    Vuyyuru, Sreedhar; Ravuri, Sreenivas R; Tandra, Vamsidhar R; Panigrahi, Manas K

    2009-07-01

    We describe the extrusion of a ventriculo peritoneal shunt tube from the anus into a 6-year-old boy following the placement of a ventriculo peritoneal shunt for postoperative periventricular tumor-induced hydrocephalus. He was admitted with a complaint of extrusion of a tube through anus on and off during bowel evacuation. He was evaluated with an X-ray of the abdomen which was showing a coiled tube in descending and sigmoid colon, confirmed by sigmoidoscopy. The proximal end was exposed for external ventricular drainage and distal end was removed endoscopically. The patient was watched for peritonitis and managed conservatively. The proximal end of the tube was removed after 5 days of external ventricular drainage and after ruling out ventriculitis and meningitis. Bowel perforation by a ventriculo peritoneal tube is a rare complication. Diagnosis is often difficult and delayed. Most of the bowel perforation is seen in young patients. PMID:21887196

  20. Emergency Portacaval Shunt Versus Rescue Portacaval Shunt in a Randomized Controlled Trial of Emergency Treatment of Acutely Bleeding Esophageal Varices in Cirrhosis—Part 3

    PubMed Central

    Isenberg, Jon I.; Wheeler, Henry O.; Haynes, Kevin S.; Jinich-Brook, Horacio; Rapier, Roderick; Vaida, Florin; Hye, Robert J.

    2010-01-01

    Background Emergency treatment of bleeding esophageal varices in cirrhosis is of singular importance because of the high mortality rate. Emergency portacaval shunt is rarely used today because of the belief, unsubstantiated by long-term randomized trials, that it causes frequent portal-systemic encephalopathy and liver failure. Consequently, portacaval shunt has been relegated solely to salvage therapy when endoscopic and pharmacologic therapies have failed. Question: Is the regimen of endoscopic sclerotherapy with rescue portacaval shunt for failure to control bleeding varices superior to emergency portacaval shunt? A unique opportunity to answer this question was provided by a randomized controlled trial of endoscopic sclerotherapy versus emergency portacaval shunt conducted from 1988 to 2005. Methods Unselected consecutive cirrhotic patients with acute bleeding esophageal varices were randomized to endoscopic sclerotherapy (n = 106) or emergency portacaval shunt (n = 105). Diagnostic workup was completed and treatment was initiated within 8 h. Failure of endoscopic sclerotherapy was defined by strict criteria and treated by rescue portacaval shunt (n = 50) whenever possible. Ninety-six percent of patients had more than 10 years of follow-up or until death. Results Comparison of emergency portacaval shunt and endoscopic sclerotherapy followed by rescue portacaval shunt showed the following differences in measurements of outcomes: (1) survival after 5 years (72% versus 22%), 10 years (46% versus 16%), and 15 years (46% versus 0%); (2) median post-shunt survival (6.18 versus 1.99 years); (3) mean requirements of packed red blood cell units (17.85 versus 27.80); (4) incidence of recurrent portal-systemic encephalopathy (15% versus 43%); (5) 5-year change in Child’s class showing improvement (59% versus 19%) or worsening (8% versus 44%); (6) mean quality of life points in which lower is better (13.89 versus 27.89); and (7) mean cost of care per

  1. Results of Trabectome Surgery Following Failed Glaucoma Tube Shunt Implantation

    PubMed Central

    Mosaed, Sameh; Chak, Garrick; Haider, Asghar; Lin, Ken Y.; Minckler, Don S.

    2015-01-01

    Abstract To evaluate the safety and efficacy of Trabectome after failed tube shunt surgery. Twenty patients with prior failed tube shunt surgery who underwent Trabectome alone were included. All patients had at least 3 months of follow-up. Outcomes measured included intraocular pressure (IOP), glaucoma medications, and secondary glaucoma surgeries. The success for Kaplan–Meier survival analysis is defined as IOP ≤21 mm Hg, IOP reduced by at least 20% from preoperative IOP, and no secondary glaucoma surgery. Mean preoperative IOP was 23.7 ± 6.4 mm Hg and mean number of glaucoma medications was 3.2 ± 1.5. At 12 months, IOP was reduced to 15.5 ± 3.2 mm Hg (P = 0.05) and number of medications was reduced to 2.4 ± 1.5 (P = 0.44). Survival rate at 12 months was 84% and 3 patients required additional glaucoma surgery with 15 patients reaching 12 months follow-up. Other than failure of IOP control and transient hypotony (IOP < 3 mm Hg) day 1 in 2 cases, there were no adverse events. Trabecular bypass procedures have traditionally been considered an approach appropriate for early-to-moderate glaucoma; however, our study indicates benefit in refractory glaucoma as well. Eyes that are prone to conjunctival scarring and hypertrophic wound healing, such as those who have failed tube shunt surgery, may benefit from procedures that avoid conjunctival incision such as Trabectome. This study indicates potential benefits in this patient population. Trabectome was safe and effective in reducing IOP at 1-year follow-up in patients with prior failed tube shunt surgery, but not effective in reducing medication reliance in these patients. PMID:26222842

  2. Resonance features of coupled Josephson junctions: radiation and shunting

    NASA Astrophysics Data System (ADS)

    Shukrinov, Yu M.; Seidel, P.; Il'ichev, E.; Nawrocki, W.; Grajcar, M.; Plecenik, P. A.; Rahmonov, I. R.; Kulikov, K.

    2012-11-01

    We study the phase dynamics and the resonance features of coupled Josephson junctions in layered superconductors and their manifestations in the current- voltage characteristics and temporal dependence of the electric charge in the superconducting layers. Results on the effect of the external radiation and shunting of the stack of Josephson junctions by LC-elements are presented. We discuss the ideas concerning the experimental observation of these resonances.

  3. Modified Blalock-Taussig Shunt with an Umbilical Vein Graft

    PubMed Central

    Leão, Luiz Eduardo V.; Andrade, José Carlos S.; Succi, José Ernesto; Cueva, Clotario C.; Ribeiro, Expedito E.; Carvalho, Antonio Carlos C.; Buffolo, Enio

    1985-01-01

    We describe a modification of the Blalock Taussig anastomosis, with the interposition of a glutaraldehyde-tanned umbilical vein graft between the subclavian and pulmonary arteries. This operation was performed in 64 children: 11 were less than 1 month of age (17.2%), and 23 were between 1 and 6 months of age (34.9%). Hospital deaths occurred in six patients—all less than 6 months of age (9.4%). There was no instance of shunt occlusion noted. The clinical course was uneventful among survivors, except for one patient who died of endocarditis in the late postoperative follow-up. The shunt procedure may be performed very rapidly, with minimal dissection, allowing the use of a graft larger than the diameter of the subclavian artery. This modification of the Blalock Taussig operation compares favorably with our previous experience with other shunt procedures and may be considered a valuable alternative in the palliative surgical treatment of several malformations with severe pulmonary oligemia. Images PMID:15227043

  4. Hysteresis Control for Current Harmonics Suppression Using Shunt Active Filter

    NASA Astrophysics Data System (ADS)

    Ahuja, Rajesh Kr; Chauhan, Aasha; Sharma, Sachin

    2012-11-01

    Recently wide spread of power electronic equipment has caused an increase of the harmonic disturbances in the power systems. The nonlinear loads draw harmonic and reactive power components of current from ac mains. Current harmonics generated by nonlinear loads such as adjustable speed drives,static powersupplies and UPS. Thus a perfect compensator is required to avoid the consequences due to harmonics. To overcome problems due to harmonics, Shunt Active Power Filter (SAPF) has been considered extensively. SAPF has better harmonic compensation than the other approaches used for solving the harmonic related problems. The performance of the SAPF depends upon different control strategies. This paper presents the performance analysis of SAPF under most important control strategy namely instantaneous real active and reactive power method (p-q) for extracting reference currents of shunt active filters under unbalanced load condition. Detailed simulations have been carried out considering this control strategy and adequate results were presented. In this paper, harmonic control strategy is applied to compensate the current harmonics in the system. A detailed study about the harmonic control method has been used using shunt active filter technique.

  5. Depiction of ventriculoperitoneal shunt obstruction with single-photon emission computed tomography/computed tomography

    PubMed Central

    Aksoy, Sabire Yılmaz; Vatankulu, Betül; Uslu, Lebriz; Halac, Metin

    2016-01-01

    An 83-year-old male patient with ventriculoperitoneal shunt underwent radionuclide shunt study using single-photon emission computed tomography/computed tomography (SPECT/CT) to evaluate the shunt patency. The planar images showed activity at the cranial region and spinal canal but no significant activity at the peritoneal cavity. However, SPECT/CT images clearly demonstrated accumulation of activity at the superior part of bifurcation level with no activity at the distal end of shunt as well as no spilling of radiotracer into the peritoneal cavity indicating shunt obstruction. SPECT/CT makes the interpretation of radionuclide shunt study more accurate and easier as compared with traditional planar images. PMID:27385906

  6. Infection as a cause of peritoneal catheter dysfunction in ventriculo-peritoneal shunting in children.

    PubMed

    Frykberg, T; Olden, L

    1983-12-01

    Peritoneal catheter dysfunction is a significant complication of VP shunting in children. Improvement in technique and material should reduce complications such as detachment and breakage. Shunt infection, even if subclinical, should be suspected as the cause of early peritoneal catheter obstruction, especially if recurrent, as well as in cases of organ perforation. Cultures, prolonged if necessary, should be taken and infection should be treated prior to shunt revision. We have had no recurrence of infection or peritoneal catheter dysfunction after treatment with exteriorization of the infected shunt, antibiotic therapy and insertion of a new shunt on the contralateral side. In infected cases antibiotic therapy, both pre- and intra-operatively, should be a matter of course. With these precautions a better result with the ventriculo-peritoneal shunt should be achieved.

  7. Chemoembolic Hepatopulmonary Shunt Reduction to Allow Safe Yttrium-90 Radioembolization Lobectomy of Hepatocellular Carcinoma

    SciTech Connect

    Gaba, Ron C.; VanMiddlesworth, Kyle A.

    2012-12-15

    Yttrium-90 ({sup 90}Y) radioembolization represents an emerging transcatheter treatment option for the management of hepatocellular carcinoma (HCC). Elevation of the hepatopulmonary shunt fraction risks nontarget radiation to the lungs and may limit the use of {sup 90}Y therapy in patients with locally advanced disease with vascular invasion, who often demonstrate increased shunting. We present two cases in which patients with HCC and portal vein invasion resulting in elevated hepatopulmonary shunt fractions underwent chemoembolic shunt closure to allow safe {sup 90}Y radioembolization. Both patients demonstrated excellent tumor response and patient survival. On this basis, we propose a role for chemoembolic reduction of the lung shunt fraction before {sup 90}Y radioembolization in patients with extensive tumor-related hepatopulmonary shunting.

  8. Development of chronic hepatocerebral degeneration eight years after a distal splenorenal (Warren) shunt.

    PubMed Central

    Bleasel, A F; Waugh, R C; McCaughan, G W

    1989-01-01

    It is well known that chronic encephalopathy may be a major complication after the establishment of a surgical portal caval shunt for an episode of variceal haemorrhage. In an effort to minimise this problem Warren and colleagues developed the distal splenorenal shunt where the portal and mesenteric blood flow to the liver was left intact. It is now recognised, however, that the longterm incidence of encephalopathy may be no different with this type of shunt compared with conventional surgical portal systemic shunts. Acquired chronic hepatocerebral degeneration has not been reported after such a selective shunt. A patient with primary biliary cirrhosis is reported who developed the clinical features of this syndrome eight years after a successful distal splenorenal shunt. Images Fig. 1 Fig. 2 PMID:2583570

  9. A multi-stack simulation of shunt currents in vanadium redox flow batteries

    NASA Astrophysics Data System (ADS)

    Wandschneider, F. T.; Röhm, S.; Fischer, P.; Pinkwart, K.; Tübke, J.; Nirschl, H.

    2014-09-01

    A model for the shunt currents in an all-vanadium redox flow battery consisting of 3 stacks which are electrically connected in series. It is based on an equivalent circuit which treats the shunt current pathways as Ohmic resistors. The conductivity of the vanadium electrolyte has been measured for different state-of-charges in order to implement a dependency of the resistances on the state-of-charge of the system. Published results are used to validate the simulation data of a single stack. Three setups of pipe networks are evaluated using the model. The pipe connections between the stacks give rise to external shunt currents, which also increase the amount of shunt currents within the stacks. These connections also lead to a nonuniform distribution of the shunt currents. The effects of the shunt currents on the Coulombic efficiency and the energy efficiency of the system are studied by the means of the model.

  10. Huntington disease: pathogenesis and treatment.

    PubMed

    Dayalu, Praveen; Albin, Roger L

    2015-02-01

    Huntington disease (HD) is an autosomal dominant inherited neurodegenerative disease characterized by progressive motor, behavioral, and cognitive decline, culminating in death. It is caused by an expanded CAG repeat in the huntingtin gene. Even years before symptoms become overt, mutation carriers show subtle but progressive striatal and cerebral white matter atrophy by volumetric MRI. Although there is currently no direct treatment of HD, management options are available for several symptoms. A better understanding of HD pathogenesis, and more sophisticated clinical trials using newer biomarkers, may lead to meaningful treatments. This article reviews the current knowledge of HD pathogenesis and treatment.

  11. [Latest aspects in psoriasis pathogenesis].

    PubMed

    Prinz, J C

    2003-03-01

    During recent years the understanding of psoriasis pathogenesis has changed essentially. Psoriasis is now considered as a T cell mediated inflammation of the skin. Genetic predisposition and microbial environment cooperate in the induction of an antigen-specific T cell mediated immune response which may persist lifelong. The phenotype of the psoriatic inflammation is determined by the particular functional differentiation of the pathogenic T cells. The progress in understanding the pathogenesis of psoriasis has identified T cells and T cell-derived cytokines as targets for causal treatment approaches that in the near future will change psoriasis therapy considerably.

  12. CSF hydrothorax without intrathoracic catheter migration in children with ventriculoperitoneal shunt

    PubMed Central

    Kim, Joon-Hyung; Roberts, David W.; Bauer, David F.

    2015-01-01

    Background: Thoracic complications of ventriculoperitoneal (VP) shunts have been extensively reported in the literature. Cerebrospinal fluid (CSF) hydrothorax without catheter migration, however, has been rarely described and poorly understood. Case Description: We describe development of pleural effusion and respiratory distress in a 3-year-old boy with no evidence of VP shunt catheter displacement on plain radiograph and stable ventricle size on rapid sequence magnetic resonance imaging (MRI) brain. Chest X-ray revealed complete opacity of right hemithorax. Pleural effusion was consistent with transudate. Beta-2 transferrin returned positive. The patient underwent externalization of VP shunt, and upon resolution of effusion, re-internalization with new distal shunt catheter. A literature review of CSF hydrothorax in children without intrathoracic shunt migration was performed. Eleven cases were identified in the English literature. Age at VP shunt placement ranged from birth to 8 years of age. Interval from VP shunt placement to CSF hydrothorax ranged from 1.5 months to 5 years. History of shunt revision was reported in two cases. Presenting symptoms also included ascites and inguinal hernia or hydrocele. Reported diagnostic studies consist of CSF culture, radionuclide shuntogram, beta-2 transferrin, and beta-trace protein. Laterality of the VP shunt and development of pleural effusion were predominantly right sided. Definitive surgical treatment included VA shunt, repositioning of the peritoneal catheter, and endoscopic choroid plexus coagulation. Conclusion: CSF hydrothorax is a rare thoracic complication of VP shunt placement with no radiographic evidence of shunt migration or malfunction. Postulated mechanisms include limited peritoneal capacity to resorb CSF in children and microscopic communications present in congenital diaphragmatic hiatuses. PMID:26236552

  13. The complementary role of plain radiographs and radionuclide shuntography in evaluating CSF-VP shunts.

    PubMed

    Blair, K; AuCoin, R; Kloiber, R; Molnar, C P

    1989-02-01

    Cerebrospinal fluid-ventriculoperitoneal shunts are often used in the treatment of hydrocephalus in children. Many complications can arise that may lead to shunt malfunction, including detachment of the distal limb of the shunt. A case is presented where such a complication occurred with distal migration of the detached tubing into the abdomen, which resulted in a patent subcutaneous tract through which cerebrospinal fluid could drain. The need for radiographic correlation at the time of radionuclide shuntography is stressed.

  14. Treatment and microbiology of repeated cerebrospinal fluid shunt infections in children

    PubMed Central

    Tuan, Teresa J; Thorell, Emily A; Hamblett, Nicole Mayer; Kestle, John R. W.; Rosenfeld, Margaret; Simon, Tamara D

    2011-01-01

    Background A small group of children have second and even more cerebrospinal fluid (CSF) shunt infections (SI). We sought to describe the treatment approaches used for, and the microbiology of, repeated shunt infections. Methods The study population included 31 children with second shunt infection (SI-2) among those undergoing initial CSF shunt placement and treatment for initial infection at Primary Children’s Medical Center. CSF shunt infection was defined as: 1) presence of bacteria in Gram stain and/or culture of CSF, wound, and/or pseudocyst; 2) visible hardware; or 3) abdominal pseudocyst; or (4) presence of bacteria in a blood culture in children with a ventriculoatrial shunt. Infection rates were generated using per-patient denominators, and the concordance of organisms across infections was summarized. Results Of the 31 children with SI-2, most were less than 6 months of age at initial shunt placement (81%), male (77%), and with ventriculoperitoneal shunts (71%). Eighteen developed SI-3 and 8 developed SI-4. Infection rates were 60% (95% confidence interval (CI): 42–75%, n=18/30) for SI-3 and 47% (95% CI: 26–69%, n=8/17) for SI-4. The median time to SI-3 was 477 days (range 5–828) and to SI-4 was 2137 days (range 9–2137). Gram-positive organisms predominated (93% of SI-2, 94% of SI-3). The majority of second shunt infections demonstrated Gram-stain concordance with both the initial (first) shunt infection (58%, 95% CI: 41–74%) and with the following (third) shunt infection (78%, 95% CI: 55–91%). Conclusions Children with second shunt infection experience high subsequent re-infection rates with a long time to re-infection. PMID:21852762

  15. Reversibility of intrapulmonary arteriovenous shunts in liver cirrhosis documented by serial radionuclide perfusion lung scans

    SciTech Connect

    Chen, N.S.; Barnett, C.A.; Farrer, P.A.

    1984-05-01

    Using serial perfusion lung scans, the opening up and closure of right-to-left intrapulmonary arteriovenous shunts has been documented over a period of several weeks in a patient with chronic alcoholic liver disease. The presence of the shunts correlates well with the severity of hypoxemia and the presence of nodular mottling on chest radiographs. The time course of these changes with clinical status suggests lability and the functional nature of these shunts.

  16. Gold shunt for refractory advanced low-tension glaucoma with spared central acuity

    PubMed Central

    Le, Ryan; Gupta, Neeru

    2016-01-01

    The aim of this study is to report a case of gold shunt surgery for uncontrolled, low-tension glaucoma with good central vision, after having a previously failed trabeculectomy and tube shunt surgeries. The patient was receiving maximum medical glaucoma therapy of four different types with intraocular pressure of 17 mm Hg prior to gold shunt surgery. Five years later, intraocular pressure is well controlled in the low teens without the need for ocular medications, and glaucoma is stable following gold shunt surgery. PMID:27051320

  17. Hydrocele of the canal of Nuck as a result of a rare ventriculoperitoneal shunt complication.

    PubMed

    Yuksel, K Z; Senoglu, M; Yuksel, M; Ozkan, K U

    2006-01-01

    Patients with ventriculoperitoneal (VP) shunts may have multiple complications. Migration of the peritoneal catheter into some anatomical or congenitally open cavities can cause inguinal or genitourinary manifestations such as hernia, hydrocele or acute scrotum, and these are common in male infants. We report a very rare complication of VP shunt encountered in a female infant, manifesting as hydrocele of the canal of Nuck, the female counterpart of hydrocele of the spermatic cord. It is emphasized that VP shunts may also cause clinical inguinal manifestations in female infants, and groin or external genital organ swelling in these patients may be an important sign of shunt malfunction.

  18. Evidence for a patent fibrous tract in fractured, outgrown, or disconnected ventriculoperitoneal shunts.

    PubMed

    Clyde, B L; Albright, A L

    1995-01-01

    As cerebrospinal fluid (CSF) shunts function for several years, outgrowth and disconnection of the distal catheter are seen more frequently. Though a shunt revision is clearly indicated if patients are symptomatic, asymptomatic patients with a disconnection or who have outgrown the distal catheter may no longer require CSF diversion. This follows an assumption that the shunt is no longer functioning and, in an asymptomatic patient, no longer required. However, patent fibrous tracts have been postulated which may allow passage of CSF through disconnected or outgrown distal catheters. We have recently treated 2 patients with ventriculoperitoneal (VP) shunts with evidence of a persistent fibrous tract. A 13-year-old boy was asymptomatic for 2 years after radiographs revealed an outgrown distal VP shunt catheter, after which the acutely deteriorated and died from massive hydrocephalus, although the entire shunt was patent. Another 14-year-old boy who was profoundly retarded presented with subtle changes in his daily activity. Shunt radiographs revealed two disconnections and a broken valve, but a shunt tap revealed a normal opening pressure (OP). A radionuclide shuntogram revealed rapid passage of isotope through fibrous sheaths at the disconnections, and into the peritoneum. A shunt revision was performed and the patient returned to his previous level of health. Patients with outgrown or disconnected distal catheters may be asymptomatic and/or have normal OP, and must not be assumed to have arrested hydrocephalus. A ventricular pressure measurement and radionuclide shuntogram should be performed to rule out a patent persistent fibrous tract.

  19. PORTACAVAL SHUNT IN PATIENTS WITH CIRRHOSIS—After-Effects of the Operation

    PubMed Central

    Benson, John A.

    1961-01-01

    The subject of the indications for operation for portacaval shunt bristles with problems to which a satisfactory answer cannot yet be given. I have discussed those events which supervene after a portacaval shunt which, in the present state of knowledge, has been directed as proper and well-intentioned therapy. It is against the knowledge of such post-shunt events and the complexity of their management, as well as the success of the operation and the risk of mortality, that one must balance the indications for surgery. This is particularly pertinent to the application of prophylactic shunt surgery now under consideration. PMID:18732366

  20. Robert H. Pudenz (1911-1998) and Ventriculoatrial Shunt: Historical Perspective.

    PubMed

    Konar, Subhas K; Maiti, Tanmoy K; Bir, Shyamal C; Kalakoti, Piyush; Nanda, Anil

    2015-11-01

    Robert H. Pudenz was a renowned neurosurgeon in North America in the 20th century, famous for his contributions in the evolution of the shunt valve and ventriculoatrial shunt surgery. With his innovative idea and help from Heyer, in 1955, he demonstrated that a venous catheter worked best when in the right atrium and that the slit valve should be located at the most distal portion of the shunt system to prevent retrograde filling and thrombosis. He also contributed to various experimental studies on the brain, especially the electrical response of different neural structures. This historical vignette focuses on the work of Robert Pudenz and the evolution of the ventriculoatrial shunt.

  1. Spontaneous knot formation in the peritoneal catheter: a rare cause of ventriculoperitoneal shunt malfunction.

    PubMed

    Charalambides, Constantinos; Sgouros, Spyros

    2012-01-01

    Ventriculoperitoneal shunt malfunction is a relatively common problem encountered in shunted hydrocephalic patients and is attributed most frequently to mechanical obstruction of the ventricular catheter. We present the case of a rare cause of mechanical obstruction of the peritoneal catheter due to the spontaneous formation of a knot just underneath the abdominal wound. This occurred 1 year after shunt implantation and is thought to have been caused by a combination of plastic material memory and bowel peristaltic movements. This case brings for discussion the role of radiographic investigation of the shunt system in children who present with suspected shunt obstruction. Radiographic investigation is warranted in children who have unusual shunt arrangements (e.g., Y-connectors and multiple catheters) in order to exclude disconnections or those who develop shunt problems years after implantation, to exclude material fracture in the neck or migration of any kind. In shunt systems which have been implanted for shorter time periods, the need for radiographs is less apparent. Some surgeons proclaim that when clinical circumstances fall outside the realms of obvious possible proximal obstruction, radiographic evaluation of the shunt system should be considered. PMID:23816925

  2. The role of persistent foramen ovale and other shunts in decompression illness.

    PubMed

    Wilmshurst, Peter T

    2015-06-01

    A persistent foramen ovale (PFO) and other types of right-to-left shunts are associated with neurological, cutaneous and cardiovascular decompression illness (DCI). A right-to-left shunt is particularly likely to be implicated in causation when these types of DCI occur after dives that are not provocative. It is believed that venous nitrogen bubbles that form after decompression pass through the shunt to circumvent the lung filter and invade systemic tissues supersaturated with nitrogen (or other inert gas) and as a result there is peripheral amplification of bubble emboli in those tissues. Approximately a quarter of the population have a PFO, but only a small proportion of the population with the largest right-to-left shunts are at high risk of shunt-mediated DCI. The increased risk of DCI in people with migraine with aura is because migraine with aura is also associated with right-to-left shunts and this increased risk of DCI appears to be confi ned to those with a large PFO or other large shunt. Various ultrasound techniques can be used to detect and assess the size of right-to-left shunts by imaging the appearance of bubble contrast in the systemic circulation after intravenous injection. In divers with a history of shunt-mediated DCI, methods to reduce the risk of recurrence include cessation of diving, modification of future dives to prevent venous bubble liberation and transcatheter closure of a PFO.

  3. The role of persistent foramen ovale and other shunts in decompression illness.

    PubMed

    Wilmshurst, Peter T

    2015-06-01

    A persistent foramen ovale (PFO) and other types of right-to-left shunts are associated with neurological, cutaneous and cardiovascular decompression illness (DCI). A right-to-left shunt is particularly likely to be implicated in causation when these types of DCI occur after dives that are not provocative. It is believed that venous nitrogen bubbles that form after decompression pass through the shunt to circumvent the lung filter and invade systemic tissues supersaturated with nitrogen (or other inert gas) and as a result there is peripheral amplification of bubble emboli in those tissues. Approximately a quarter of the population have a PFO, but only a small proportion of the population with the largest right-to-left shunts are at high risk of shunt-mediated DCI. The increased risk of DCI in people with migraine with aura is because migraine with aura is also associated with right-to-left shunts and this increased risk of DCI appears to be confi ned to those with a large PFO or other large shunt. Various ultrasound techniques can be used to detect and assess the size of right-to-left shunts by imaging the appearance of bubble contrast in the systemic circulation after intravenous injection. In divers with a history of shunt-mediated DCI, methods to reduce the risk of recurrence include cessation of diving, modification of future dives to prevent venous bubble liberation and transcatheter closure of a PFO. PMID:26165532

  4. Optimization of shunt placement for the Norwood surgery using multi-domain modeling.

    PubMed

    Moghadam, Mahdi Esmaily; Migliavacca, Francesco; Vignon-Clementel, Irene E; Hsia, Tain-Yen; Marsden, Alison L

    2012-05-01

    An idealized systemic-to-pulmonary shunt anatomy is parameterized and coupled to a closed loop, lumped parameter network (LPN) in a multidomain model of the Norwood surgical anatomy. The LPN approach is essential for obtaining information on global changes in cardiac output and oxygen delivery resulting from changes in local geometry and physiology. The LPN is fully coupled to a custom 3D finite element solver using a semi-implicit approach to model the heart and downstream circulation. This closed loop multidomain model is then integrated with a fully automated derivative-free optimization algorithm to obtain optimal shunt geometries with variable parameters of shunt diameter, anastomosis location, and angles. Three objective functions: (1) systemic; (2) coronary; and (3) combined systemic and coronary oxygen deliveries are maximized. Results show that a smaller shunt diameter with a distal shunt-brachiocephalic anastomosis is optimal for systemic oxygen delivery, whereas a more proximal anastomosis is optimal for coronary oxygen delivery and a shunt between these two anatomies is optimal for both systemic and coronary oxygen deliveries. Results are used to quantify the origin of blood flow going through the shunt and its relationship with shunt geometry. Results show that coronary artery flow is directly related to shunt position. PMID:22757490

  5. Embolization of portal-systemic shunts in cirrhotic patients with chronic recurrent hepatic encephalopathy

    SciTech Connect

    Sakurabayashi, Shin; Sezai, Shuichi; Yamamoto, Yoshihiro; Hirano, Masanori; Oka, Hiroshi

    1997-03-15

    Purpose. To evaluate the efficacy of embolization of portal-systemic shunts in cirrhotic patients with chronic recurrent hepatic encephalopathy (CRHE). Methods. Seven cirrhotic patients with CRHE refractory to medical treatment (3 men and 4 women, mean age 66 years) were studied. Five patients had splenorenal shunts, 1 had a gastrorenal shunt, and 1 had an intrahepatic portal vein-hepatic vein shunt. Shunt embolization was performed using stainless steel coils, with a percutaneous transhepatic portal vein approach in 4 patients and a transrenal vein approach in 3 patients. Results. After embolization, the shunt disappeared in 4 patients on either ultrasound pulsed Doppler monitoring or portography. Complications observed in the 7 patients were fever, transient pleural effusion, ascites, and mild esophageal varices. For 3-6 months after embolization, the 4 patients whose shunts disappeared showed minimal or no reappearance of a shunt, and had no recurrence of encephalopathy. The serum ammonia levels decreased and electroencephalograms also improved. One of the 4 patients, who developed mild esophageal varices, required no treatment. Treatment was effective in 3 of the 4 patients (75%) who underwent embolization via a transhepatic portal vein. Conclusion. Transvascular embolization of shunts improved the outcome in 4 of 7 patients. The most effective embolization was achieved via the percutaneous transhepatic portal vein approach.

  6. Ventriculo-peritoneal shunt malfunction due to complete migration and subgaleal coiling of the proximal and distal catheters.

    PubMed

    Pikis, Stylianos; Cohen, José E; Shoshan, Yigal; Benifla, Mony

    2015-01-01

    Ventriculo-peritoneal (VP) shunt malfunction due to proximal and distal catheter migration has been rarely reported in the literature. Shunt migration has been proposed to occur as a result of a combination of various mechanisms, including the windlass effect, retained memory of the shunt tubing, inadequate shunt fixation, and increased intra-abdominal pressures. We describe a rare case of a 6-week-old child who presented in our department with VP shunt malfunction due to complete proximal migration and coiling of the peritoneal and ventricular VP shunt catheters within a subgaleal pocket at the left occipital area.

  7. Pathogenesis of hepatic encephalopathy: role of ammonia and systemic inflammation.

    PubMed

    Aldridge, Dominic R; Tranah, Edward J; Shawcross, Debbie L

    2015-03-01

    The syndrome we refer to as Hepatic Encephalopathy (HE) was first characterized by a team of Nobel Prize winning physiologists led by Pavlov and Nencki at the Imperial Institute of Experimental Medicine in Russia in the 1890's. This focused upon the key observation that performing a portocaval shunt, which bypassed nitrogen-rich blood away from the liver, induced elevated blood and brain ammonia concentrations in association with profound neurobehavioral changes. There exists however a spectrum of metabolic encephalopathies attributable to a variety (or even absence) of liver hepatocellular dysfunctions and it is this spectrum rather than a single disease entity that has come to be defined as HE. Differences in the underlying pathophysiology, treatment responses and outcomes can therefore be highly variable between acute and chronic HE. The term also fails to articulate quite how systemic the syndrome of HE can be and how it can be influenced by the gastrointestinal, renal, nervous, or immune systems without any change in background liver function. The pathogenesis of HE therefore encapsulates a complex network of interdependent organ systems which as yet remain poorly characterized. There is nonetheless a growing recognition that there is a complex but influential synergistic relationship between ammonia, inflammation (sterile and non-sterile) and oxidative stress in the pathogenesis HE which develops in an environment of functional immunoparesis in patients with liver dysfunction. Therapeutic strategies are thus moving further away from the traditional specialty of hepatology and more towards novel immune and inflammatory targets which will be discussed in this review. PMID:26041962

  8. Pathogenesis of Hepatic Encephalopathy: Role of Ammonia and Systemic Inflammation

    PubMed Central

    Aldridge, Dominic R.; Tranah, Edward J.; Shawcross, Debbie L.

    2015-01-01

    The syndrome we refer to as Hepatic Encephalopathy (HE) was first characterized by a team of Nobel Prize winning physiologists led by Pavlov and Nencki at the Imperial Institute of Experimental Medicine in Russia in the 1890's. This focused upon the key observation that performing a portocaval shunt, which bypassed nitrogen-rich blood away from the liver, induced elevated blood and brain ammonia concentrations in association with profound neurobehavioral changes. There exists however a spectrum of metabolic encephalopathies attributable to a variety (or even absence) of liver hepatocellular dysfunctions and it is this spectrum rather than a single disease entity that has come to be defined as HE. Differences in the underlying pathophysiology, treatment responses and outcomes can therefore be highly variable between acute and chronic HE. The term also fails to articulate quite how systemic the syndrome of HE can be and how it can be influenced by the gastrointestinal, renal, nervous, or immune systems without any change in background liver function. The pathogenesis of HE therefore encapsulates a complex network of interdependent organ systems which as yet remain poorly characterized. There is nonetheless a growing recognition that there is a complex but influential synergistic relationship between ammonia, inflammation (sterile and non-sterile) and oxidative stress in the pathogenesis HE which develops in an environment of functional immunoparesis in patients with liver dysfunction. Therapeutic strategies are thus moving further away from the traditional specialty of hepatology and more towards novel immune and inflammatory targets which will be discussed in this review. PMID:26041962

  9. Interatrial shunt flow profiles in newborn infants: a colour flow and pulsed Doppler echocardiographic study.

    PubMed Central

    Hiraishi, S; Agata, Y; Saito, K; Oguchi, K; Misawa, H; Fujino, N; Horiguchi, Y; Yashiro, K

    1991-01-01

    Interatrial shunt flow profiles in 36 normal term infants were examined serially by colour flow and pulsed Doppler echocardiographic techniques from within an hour of birth to four or five days after birth. Shunt flow across the foramen ovale was detected in 33 normal infants (92%) within an hour of birth (mean 40 minutes). The occurrence of interatrial shunting decreased with age, but a shunt signal was still detected in 17 infants (47%) on the fourth or fifth day of life, by then the ductus arteriosus had already closed in all the normal infants. The direction of interatrial shunt flow was predominantly left-to-right, but in 64% there was a coexistent small right-to-left shunt in diastole within an hour of birth; by four to five days it was found in 19%. In the six patients with persistent fetal circulation the direction of the interatrial shunt flow was predominantly right-to-left with biphasic peaks in diastole and systole at the early stage of the disease, and the period of right-to-left shunt flow during each cardiac cycle was significantly longer than that in normal infants examined within 1 hour of birth. In all patients the ductus closed before the foramen ovale. At the time of ductal closure in all patients with persistent fetal circulation right-to-left shunt flow was seen during diastole and its period was still prolonged. These findings suggest that interatrial shunting, predominantly left-to-right, is common in normal newborn infants. Evaluation of the characteristics of the interatrial shunt by Doppler echocardiography may be useful for predicting the progress of or improvement in neonates with persistent fetal circulation. Images PMID:1993129

  10. Shunting arc plasma source for pure carbon ion beam.

    PubMed

    Koguchi, H; Sakakita, H; Kiyama, S; Shimada, T; Sato, Y; Hirano, Y

    2012-02-01

    A plasma source is developed using a coaxial shunting arc plasma gun to extract a pure carbon ion beam. The pure carbon ion beam is a new type of deposition system for diamond and other carbon materials. Our plasma device generates pure carbon plasma from solid-state carbon material without using a hydrocarbon gas such as methane gas, and the plasma does not contain any hydrogen. The ion saturation current of the discharge measured by a double probe is about 0.2 mA∕mm(2) at the peak of the pulse.

  11. Shunting arc plasma source for pure carbon ion beama)

    NASA Astrophysics Data System (ADS)

    Koguchi, H.; Sakakita, H.; Kiyama, S.; Shimada, T.; Sato, Y.; Hirano, Y.

    2012-02-01

    A plasma source is developed using a coaxial shunting arc plasma gun to extract a pure carbon ion beam. The pure carbon ion beam is a new type of deposition system for diamond and other carbon materials. Our plasma device generates pure carbon plasma from solid-state carbon material without using a hydrocarbon gas such as methane gas, and the plasma does not contain any hydrogen. The ion saturation current of the discharge measured by a double probe is about 0.2 mA/mm2 at the peak of the pulse.

  12. Laparoscopic removal of dislocated ventriculoperitoneal shunts. Report of two cases.

    PubMed

    Schrenk, P; Woisetschläger, R; Wayand, W U; Polanski, P

    1994-09-01

    In two patients the dislocated abdominal catheter of a ventriculoperitoneal (VP) shunt was successfully removed from the abdominal cavity by laparoscopy. Avoiding laparotomy, only two small abdominal incisions were necessary to insert the laparoscope and the grasping forceps. Postoperative course was uncomplicated except for protrusion of a part of the greater omentum through the umbilical incision in one patient. Both patients were mobilized on the operative day. Surgery required only 10 min, provided an excellent view of the entire abdomen, and led to prompt identification and removal of the lost catheter.

  13. Piezoelectric vibration damping using resonant shunt circuits: an exact solution

    NASA Astrophysics Data System (ADS)

    Soltani, P.; Kerschen, G.; Tondreau, G.; Deraemaeker, A.

    2014-12-01

    The objective of this paper is to propose an exact closed-form solution to the {{H}∞ } optimization of piezoelectric materials shunted with inductive-resistive passive electrical circuits. Realizing that Den Hartog's method which imposes fixed points of equal height in the receptance transfer function is approximate, the parameters of the piezoelectric tuned vibration absorber are calculated through the direct minimization of the maxima of the receptance. The method is applied to a one-degree-of-freedom primary oscillator considering various values of the electromechanical coupling coefficients.

  14. A theoretical and experimental study of coplanar waveguide shunt stubs

    NASA Technical Reports Server (NTRS)

    Dib, Nihad I.; Ponchak, George E.; Katehi, Linda P. B.

    1993-01-01

    A comprehensive theoretical and experimental study of straight and bent coplanar waveguide (CPW) shunt stubs is presented. In the theoretical analysis, the CPW is assumed to be inside a cavity while, the experiments are performed on open structures. For the analysis of CPW discontinuities with air-bridges, a hybrid technique was developed which was validated through extensive theoretical and experimental comparisons. The effect of the cavity resonances on the behavior of the stubs with and without air-bridges is investigated. In addition, the encountered radiation loss due to the discontinuities is evaluated experimentally.

  15. 69 kV shunt capacitor bank specification considerations

    SciTech Connect

    Fenner, G.E. )

    1992-01-01

    PSI has standardized on the 69 kv ungrounded star, 7.2 mvar or multiple of the 7.2 mvar shunt capacitor bank for var control. This document defines the considerations to be addressed when specifying a 69 kv ungrounded capacitor bank and for providing suitable protection. The design goal is to provide a bank that is reliable and meets operational requirements at minimum cost with standard components. The bank components will be discussed separately. This paper defines the considerations for specifying capacitor banks to minimize cost, improve reliability and help standardize design. The components making up the bank will be individually discussed with special emphasis on the protection and control.

  16. RHIC INSERTION REGION, SHUNT POWER SUPPLY CURRENT ERRORS.

    SciTech Connect

    BRUNO,D.; GANETIS,G.; LAMBIASE,R.F.; SANDBERG,J.

    2001-06-18

    The Relativistic Heavy Ion Collider (RHIC) was commissioned in 1999 and 2000. RHIC requires power supplies to supply currents to highly inductive superconducting magnets. The RHIC Insertion Region contain's many shunt power supplies to trim the current of different magnet elements in a large superconducting magnet circuit. Power Supply current error measurements were performed during the commissioning of RHIC. Models of these power supply systems were produced to predict and improve these power supply current errors using the circuit analysis program MicroCap V by Spectrum Software (TM). Results of the power supply current errors are presented from the models and from the measurements performed during the commissioning of RHIC.

  17. Nutritional rickets: pathogenesis and prevention.

    PubMed

    Pettifor, John M

    2013-06-01

    Nutritional rickets remains a public health concern in many areas of the world despite cheap and effective means of preventing the disease. The roles of vitamin D deficiency, low dietary calcium intakes and the interrelationships between the two in the pathogenesis of the disease are discussed. It is now recognized that vitamin D deficiency in the pregnant and lactating mother predisposes to the development of rickets in the breastfed infant, and that cultural and social factors are important in the pathogenesis of the disease during the adolescent growth spurt. Prevention of rickets is dependent on the awareness of the medical profession and the general public of the need to ensure adequate intakes of vitamin D in at-risk populations, and of the importance of increasing dietary intakes of calcium using locally available and inexpensive foods in communities in which dietary calcium deficiency rickets is prevalent.

  18. Time to First Shunt Failure in Pediatric Patients over 1 Year Old: A 10-Year Retrospective Study.

    PubMed

    Shannon, Chevis N; Carr, Kevin R; Tomycz, Luke; Wellons, John C; Tulipan, Noel

    2013-01-01

    Studies comparing alternatives to ventriculoperitoneal (VP) shunting for treatment of hydrocephalus have often relied upon data from an earlier era that may not be representative of contemporary shunt survival outcomes. We sought to determine the shunt survival rate of our cohort and compare our results to previously published shunt survival and endoscopic third ventriculostomy (ETV) success rates. We identified 95 patients between 1 and 18 years of age, who underwent initial VP shunt placement between January 2001 and December 2010. Our study shows a shunt survival rate of 85% at 6 months and 79% at 2 years, for initial shunts in pediatric patients over 1 year of age in this cohort. The overall infection rate was 3%. This compares favorably with published success rates of ETV at similar time points as well as with the rate of infection. This suggests that ventricular shunting remains a viable alternative to ETV in the older child.

  19. [Pathogenesis of invasive fungal infections].

    PubMed

    Garcia-Vidal, Carolina; Carratalà, Jordi

    2012-03-01

    Invasive fungal infections remain a life-threatening disease. The development of invasive fungal disease is dependent on multiple factors, such us colonization and efficient host immune response. We aimed to review the pathogenesis of invasive fungal infections, in particular, those caused by Candida and Aspergillus. For this we propose, to describe the fungal characteristics, to detail the host defence mechanisms against fungus and to analyse the host risk factors for invasive fungal infection.

  20. Epigenetics and Colorectal Cancer Pathogenesis

    PubMed Central

    Bardhan, Kankana; Liu, Kebin

    2013-01-01

    Colorectal cancer (CRC) develops through a multistage process that results from the progressive accumulation of genetic mutations, and frequently as a result of mutations in the Wnt signaling pathway. However, it has become evident over the past two decades that epigenetic alterations of the chromatin, particularly the chromatin components in the promoter regions of tumor suppressors and oncogenes, play key roles in CRC pathogenesis. Epigenetic regulation is organized at multiple levels, involving primarily DNA methylation and selective histone modifications in cancer cells. Assessment of the CRC epigenome has revealed that virtually all CRCs have aberrantly methylated genes and that the average CRC methylome has thousands of abnormally methylated genes. Although relatively less is known about the patterns of specific histone modifications in CRC, selective histone modifications and resultant chromatin conformation have been shown to act, in concert with DNA methylation, to regulate gene expression to mediate CRC pathogenesis. Moreover, it is now clear that not only DNA methylation but also histone modifications are reversible processes. The increased understanding of epigenetic regulation of gene expression in the context of CRC pathogenesis has led to development of epigenetic biomarkers for CRC diagnosis and epigenetic drugs for CRC therapy. PMID:24216997

  1. Pathogenesis of eosinophilic chronic rhinosinusitis.

    PubMed

    Shah, Said Ahmad; Ishinaga, Hajime; Takeuchi, Kazuhiko

    2016-01-01

    Eosinophilic chronic rhinosinusitis (ECRS) is considered a refractory and intractable disease. Patients with ECRS present with thick mucus production, long-term nasal congestion, loss of sense of smell, and intermittent acute exacerbations secondary to bacterial infections. Despite medical and surgical interventions, there is a high rate of recurrence with significant impairment to quality of life. The recent increasing prevalence of ECRS in south Asian countries and the strong tendency of ECRS to reoccur after surgery should be considered. The majority of cases need repeat surgery, and histological examinations of these cases show eosinophilic-dominant inflammation. The degradation and accumulation of eosinophils, release of cytokines, and mucus secretion have important roles in the pathogenesis of ECRS. ECRS differs from non-ECRS, in which eosinophils are not involved in the pathogenesis of the disease, and also in terms of many clinical characteristics, blood examination and nasal polyp histological findings, clinical features of the disease after surgery, efficacy of medications, and computed tomography findings. This review describes the clinical course, diagnosis, and treatment of ECRS as well as its pathophysiology and the role of eosinophils, mucus, cytokines, and other mediators in the pathogenesis of ECRS. PMID:27053925

  2. Transcatheter closure of modified Blalock-Taussig shunt with Gianturco-Grifka Vascular Occlusion Device.

    PubMed

    Hoyer, M H; Leon, R A; Fricker, F J

    1999-12-01

    A 15-year-old girl with previous repair of a complex cyanotic congenital heart defect had persistence of a modified left Blalock-Taussig shunt that could not be ligated at surgery. Six years later, antegrade delivery of a Gianturco-Grifka Vascular Occlusion Device resulted in complete closure of the shunt. Cathet. Cardiovasc. Intervent. 48:365-367, 1999. PMID:10559814

  3. Shunt Devices for the Treatment of Adult Hydrocephalus: Recent Progress and Characteristics

    PubMed Central

    MIYAKE, Hiroji

    2016-01-01

    Various types of shunt valves have been developed during the past 50 years, most of which can be classified into the following categories: (1) fixed differential pressure valves; (2) fixed differential pressure (DP) valves with an antisiphon mechanism; (3) programmable DP valves; (4) programmable DP valves with an antisiphon mechanism; and (5) programmable antisiphon valves. When considering the myriad of possible postoperative condition changes, such as the onset of accidental non-related diseases or trauma in adults, and changes in normal physiological development or anticipation of future shunt removal in children, it has become standard to use the programmable valve as a first choice for cerebrospinal fluid shunting. However, it is still unclear what type of shunt valve is suitable for each individual case. Based on the results of SINPHONI and more recently SINPHONI 2 trials, the programmable DP valve is recommended as the first line shunt valve. The programmable DP valve with an antisiphon mechanism is thought to be beneficial for tall, slender patients, who have a tendency for easily developing complications of overdrainage, however, this type of valve must be used cautiously in obese patients because of the increased risk of underdrainage. Although the current evidence is still insufficient, the programmable antisiphon valve, which costs the same as the programmable DP valve, is also thought to be the first line shunt valve. The quick reference table is applicable for most shunt valves, and for patients with either the ventriculoperitoneal or the lumboperitoneal shunt. PMID:27041631

  4. Immune reactions associated with silicone-based ventriculo-peritoneal shunt malfunctions in children.

    PubMed

    VandeVord, Pamela J; Gupta, Nalini; Wilson, Russell B; Vinuya, Ricardo Z; Schaefer, Caralee J; Canady, Alexa I; Wooley, Paul H

    2004-08-01

    The implantation of ventriculo-peritoneal (VP) shunting systems is the most commonly performed neurological procedure in children with hydrocephalus. Although the overall complication risk is low, the cumulative risk of shunt failure is high and unfortunately results in a high prevalence of revision surgeries. In this study, we explored the concept that some pediatric patients may develop an immune response to either the proteins attached to the silicone implant surface or to the biomaterial itself, and that this reaction may contribute to VP shunt failure in some individuals. The data displays that the sterile shunt malfunction group had a higher rate of protein deposition and increased levels of autoantibodies to the extracted surface proteins as compared to individuals with functioning shunting systems. The precise nature of the shunt-bound proteins that serve as antigens in this experiment have not yet been determined. The data also indicated that some individuals develop antibodies to polymeric substances that cross-react with partially polymerized acrylamide. The detection of significant amounts of shunt-bound protein, antibody responses to these proteins and to polymeric substances suggest that an immunological response to these proteins may play a role in the mechanism behind sterile shunt malfunctions.

  5. Two episodes of ventriculoperitoneal shunt migration in a patient with idiopathic intracranial hypertension.

    PubMed

    Balakrishnan, V; Jeanmonod, R

    2014-01-01

    Introduction. Ventriculoperitoneal shunts are often placed as treatment for refractory idiopathic intracranial hypertension. Dislodgement and migration of the distal portion of the shunt are more common in obese patients and can be difficult to detect. We report the case of a woman with two separate episodes of shunt migration into her abdominal wall. Case Presentation. We report a case of a 37-year-old female with history of obesity eventually diagnosed with idiopathic intracranial hypertension (IIH) as the cause. She failed outpatient therapy and, through neurosurgery, had a VP shunt placed for symptom control. She had subsequent development of worsened symptoms that were found to be due to shunt migration. This happened not once but twice to the same patient. Conclusion. Shunt dislodgement, migration, and subsequent failure are common in obese patients who have shunts placed for IIH. The medical provider should maintain a high index of suspicion for shunt malfunction in these patients, particularly because clinical evaluation may be challenging due to habitus.

  6. [Migration of a ventriculoperitoneal shunt in the liver: A rare complication].

    PubMed

    Eap, C; Blauwblomme, T; Dupuy, L; Bennis, S; Faber, B; Mireau, E; Aldea, S; Frileux, P; Gaillard, S

    2012-12-01

    We report on a case of migration inside the liver of the distal end of a ventriculoperitoneal shunt catheter in an adult patient. A simple laparotomy permitted the surgical removal with no haemorrhagic complication. We discuss the other cases reported in the literature and we outline the need to perform an abdominal CT scan in patients carrying a VP shunt with digestive symptoms.

  7. Visual disturbance following shunt malfunction in a patient with congenital hydrocephalus.

    PubMed

    Oyama, Hirofumi; Hattori, Kenichi; Kito, Akira; Maki, Hideki; Noda, Tomoyuki; Wada, Kentaro

    2012-01-01

    A 25-year-old woman presented with complaints of nausea and headache. She had been treated with a ventriculoperitoneal shunt for hydrocephalus when she was 7 months old. Her bilateral optic discs showed moderate atrophy. Right visual acuity allowed only perception of hand movement and left visual acuity was 0.02 (1.2). Computed tomography (CT) showed mild ventricular dilation but no periventricular lucency. Intracranial pressure (ICP) was not high when the shunt valve was punctured. Her visual acuity deteriorated 5 days after the consultation. She was referred again 8 days after the first consultation. The bilateral optic discs were completely pale. Both pupils were dilated on admission, and the bilateral direct light reflexes were absent. The patient could slightly detect only green light stimulus. CT showed moderate enlargement of the ventricle. ICP was 47 cmH(2)O when the shunt valve was punctured. Shuntgraphy showed obstruction of the shunt at the distal end of peritoneal catheter. Emergent total shunt revision was performed. She could detect dark stimulus and the still-dilated left pupil had recovered direct light reflex on the next day. The visual acuity was 0.01 (0.7) on the left 6 months after the operation, although she was blind in the right eye and the bilateral optic discs were completely pale. Visual loss associated with shunt failure remains a major morbidity in shunted congenital hydrocephalus. Early diagnosis and shunt revision may allow visual recovery.

  8. Shunt Devices for the Treatment of Adult Hydrocephalus: Recent Progress and Characteristics.

    PubMed

    Miyake, Hiroji

    2016-05-15

    Various types of shunt valves have been developed during the past 50 years, most of which can be classified into the following categories: (1) fixed differential pressure valves; (2) fixed differential pressure (DP) valves with an antisiphon mechanism; (3) programmable DP valves; (4) programmable DP valves with an antisiphon mechanism; and (5) programmable antisiphon valves. When considering the myriad of possible postoperative condition changes, such as the onset of accidental non-related diseases or trauma in adults, and changes in normal physiological development or anticipation of future shunt removal in children, it has become standard to use the programmable valve as a first choice for cerebrospinal fluid shunting. However, it is still unclear what type of shunt valve is suitable for each individual case. Based on the results of SINPHONI and more recently SINPHONI 2 trials, the programmable DP valve is recommended as the first line shunt valve. The programmable DP valve with an antisiphon mechanism is thought to be beneficial for tall, slender patients, who have a tendency for easily developing complications of overdrainage, however, this type of valve must be used cautiously in obese patients because of the increased risk of underdrainage. Although the current evidence is still insufficient, the programmable antisiphon valve, which costs the same as the programmable DP valve, is also thought to be the first line shunt valve. The quick reference table is applicable for most shunt valves, and for patients with either the ventriculoperitoneal or the lumboperitoneal shunt.

  9. Transient right-to-left shunting through a patent foramen ovale secondary to unilateral diaphragmatic paralysis.

    PubMed Central

    Cordero, P. J.; Morales, P.; Mora, V.; Cebrian, J.; Vallterra, J.; Gudin, J.; Benlloch, E.; Marco, V.

    1994-01-01

    A 57 year old patient presented with unilateral diaphragmatic paralysis and severe hypoxaemia secondary to transient right-to-left interatrial shunting through a patent foramen ovale. The final diagnosis was made because of the initial detection of a shunt while the patient was breathing 100% oxygen. Images PMID:7940438

  10. Ventriculoperitoneal shunt for treatment of hydrocephalus in a French bulldog puppy

    PubMed Central

    Giacinti, Jolene A.

    2016-01-01

    A 6.5-week-old bulldog was presented with lethargy, anorexia, and stunted growth. A domed skull, ventrolateral strabismus, hypermetria, and delayed hopping were observed. Congenital hydrocephalus was diagnosed and a ventriculoperitoneal shunt was placed. After surgery, a shunt obstruction occurred but resolved with treatment. The puppy responded well and neurological deficits continued to improve after surgery. PMID:26933271

  11. Normal-pressure hydrocephalus: current understanding of diagnostic tests and shunting

    SciTech Connect

    Black, P.M.

    1982-02-01

    Normal-pressure hydrocephalus is no longer difficult to diagnose or treat-cranial computed tomographic scanning has made the diagnosis of ventricular enlargement straightforward, and shunt placement often helps the patient whose condition can be traced to a specific cause. Predicting accurately whether a patient will benefit from a shunt, however, is still problematic.

  12. 21 CFR 882.5550 - Central nervous system fluid shunt and components.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Central nervous system fluid shunt and components. 882.5550 Section 882.5550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... shunt is a device or combination of devices used to divert fluid from the brain or other part of...

  13. 21 CFR 882.5550 - Central nervous system fluid shunt and components.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Central nervous system fluid shunt and components. 882.5550 Section 882.5550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... shunt is a device or combination of devices used to divert fluid from the brain or other part of...

  14. 21 CFR 882.5550 - Central nervous system fluid shunt and components.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Central nervous system fluid shunt and components. 882.5550 Section 882.5550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... shunt is a device or combination of devices used to divert fluid from the brain or other part of...

  15. Electroacoustic absorbers: bridging the gap between shunt loudspeakers and active sound absorption.

    PubMed

    Lissek, Hervé; Boulandet, Romain; Fleury, Romain

    2011-05-01

    The acoustic impedance at the diaphragm of an electroacoustic transducer can be varied using a range of basic electrical control strategies, amongst which are electrical shunt circuits. These passive shunt techniques are compared to active acoustic feedback techniques for controlling the acoustic impedance of an electroacoustic transducer. The formulation of feedback-based acoustic impedance control reveals formal analogies with shunt strategies, and highlights an original method for synthesizing electric networks ("shunts") with positive or negative components, bridging the gap between passive and active acoustic impedance control. This paper describes the theory unifying all these passive and active acoustic impedance control strategies, introducing the concept of electroacoustic absorbers. The equivalence between shunts and active control is first formalized through the introduction of a one-degree-of-freedom acoustic resonator accounting for both electric shunts and acoustic feedbacks. Conversely, electric networks mimicking the performances of active feedback techniques are introduced, identifying shunts with active impedance control. Simulated acoustic performances are presented, with an emphasis on formal analogies between the different control techniques. Examples of electric shunts are proposed for active sound absorption. Experimental assessments are then presented, and the paper concludes with a general discussion on the concept and potential improvements.

  16. Soluble membrane attack complex is diagnostic for intraventricular shunt infection in children

    PubMed Central

    Ramos, Theresa N.; Arynchyna, Anastasia A.; Blackburn, Tessa E.; Johnston, James M.

    2016-01-01

    BACKGROUND. Children treated with cerebrospinal fluid (CSF) shunts to manage hydrocephalus frequently develop shunt failure and/or infections, conditions that present with overlapping symptoms. The potential life-threatening nature of shunt infections requires rapid diagnosis; however, traditional microbiology is time consuming, expensive, and potentially unreliable. We set out to identify a biomarker that would identify shunt infection. METHODS. CSF was assayed for the soluble membrane attack complex (sMAC) by ELISA in patients with suspected shunt failure or infection. CSF was obtained at the time of initial surgical intervention. Statistical analysis was performed to assess the diagnostic potential of sMAC in pyogenic-infected versus noninfected patients. RESULTS. Children with pyogenic shunt infection had significantly increased sMAC levels compared with noninfected patients (3,211 ± 1,111 ng/ml vs. 26 ± 3.8 ng/ml, P = 0.0001). In infected patients undergoing serial CSF draws, sMAC levels were prognostic for both positive and negative clinical outcomes. Children with delayed, broth-only growth of commensal organisms (P. acnes, S. epidermidis, etc.) had the lowest sMAC levels (7.96 ± 1.7 ng/ml), suggesting contamination rather than shunt infection. CONCLUSION. Elevated CSF sMAC levels are both sensitive and specific for diagnosing pyogenic shunt infection and may serve as a useful prognostic biomarker during recovery from infection. FUNDING. This work was supported in part by the Impact Fund of Children’s of Alabama.

  17. Shunt Devices for the Treatment of Adult Hydrocephalus: Recent Progress and Characteristics.

    PubMed

    Miyake, Hiroji

    2016-05-15

    Various types of shunt valves have been developed during the past 50 years, most of which can be classified into the following categories: (1) fixed differential pressure valves; (2) fixed differential pressure (DP) valves with an antisiphon mechanism; (3) programmable DP valves; (4) programmable DP valves with an antisiphon mechanism; and (5) programmable antisiphon valves. When considering the myriad of possible postoperative condition changes, such as the onset of accidental non-related diseases or trauma in adults, and changes in normal physiological development or anticipation of future shunt removal in children, it has become standard to use the programmable valve as a first choice for cerebrospinal fluid shunting. However, it is still unclear what type of shunt valve is suitable for each individual case. Based on the results of SINPHONI and more recently SINPHONI 2 trials, the programmable DP valve is recommended as the first line shunt valve. The programmable DP valve with an antisiphon mechanism is thought to be beneficial for tall, slender patients, who have a tendency for easily developing complications of overdrainage, however, this type of valve must be used cautiously in obese patients because of the increased risk of underdrainage. Although the current evidence is still insufficient, the programmable antisiphon valve, which costs the same as the programmable DP valve, is also thought to be the first line shunt valve. The quick reference table is applicable for most shunt valves, and for patients with either the ventriculoperitoneal or the lumboperitoneal shunt. PMID:27041631

  18. Shunt currents in vanadium flow batteries: Measurement, modelling and implications for efficiency

    NASA Astrophysics Data System (ADS)

    Fink, H.; Remy, M.

    2015-06-01

    Shunt currents are an important factor which must be considered when designing a stack for flow batteries. They lead to a reduction of the coulombic efficiency and can cause furthermore a critical warming of the electrolyte. Shunt currents inevitably appear at bypass connections of the hydraulic system between the single cells of a stack. In this work the shunt currents of a five-celled mini stack of a vanadium flow battery with external hydraulic system and their effects are investigated directly. The external hydraulic system allows the implementation of current sensors for direct measurement of the shunt currents; moreover, the single bypass channels can be interrupted by clamping the tube couplings and with it the shunt currents between the cells when the pumps are off. Thus the shares of losses by cross contamination and by shunt currents are quantified separately by charge conservation measurements. The experimentally gained data are compared to a shunt current model based on a equivalent circuit diagram and the linear equation system derived from it. Experiments and model data are in good agreement. The effects of shunt currents for different flow frame geometries and number of cells in a stack are simulated and presented in this work.

  19. Electroacoustic absorbers: bridging the gap between shunt loudspeakers and active sound absorption.

    PubMed

    Lissek, Hervé; Boulandet, Romain; Fleury, Romain

    2011-05-01

    The acoustic impedance at the diaphragm of an electroacoustic transducer can be varied using a range of basic electrical control strategies, amongst which are electrical shunt circuits. These passive shunt techniques are compared to active acoustic feedback techniques for controlling the acoustic impedance of an electroacoustic transducer. The formulation of feedback-based acoustic impedance control reveals formal analogies with shunt strategies, and highlights an original method for synthesizing electric networks ("shunts") with positive or negative components, bridging the gap between passive and active acoustic impedance control. This paper describes the theory unifying all these passive and active acoustic impedance control strategies, introducing the concept of electroacoustic absorbers. The equivalence between shunts and active control is first formalized through the introduction of a one-degree-of-freedom acoustic resonator accounting for both electric shunts and acoustic feedbacks. Conversely, electric networks mimicking the performances of active feedback techniques are introduced, identifying shunts with active impedance control. Simulated acoustic performances are presented, with an emphasis on formal analogies between the different control techniques. Examples of electric shunts are proposed for active sound absorption. Experimental assessments are then presented, and the paper concludes with a general discussion on the concept and potential improvements. PMID:21568400

  20. Characteristic lesion pattern and echocardiographic findings in extra-cardiac shunt-related stroke.

    PubMed

    Mun, Jun Kyu; Park, Sung Ji; Kim, Suk Jae; Bang, Oh Young; Chung, Chin-Sang; Lee, Kwang Ho; Kim, Gyeong-Moon

    2016-10-15

    Among embolic strokes of undetermined source, under-recognized etiology such as extra-cardiac shunt could be a potential risk factor. We sought to characterize infarction patterns on diffusion-weighted imaging (DWI) and transesophageal echocardiography (TEE) findings in extra-cardiac shunt-related stroke. We enrolled 96 consecutive patients with cryptogenic stroke who had an extra- or intra-cardiac shunt. Diagnosis of the shunt was performed using TEE with agitated saline contrast and pulmonary vein isolation. Infarction patterns on DWI and total lesion volume were analyzed. Bubble amounts through the shunt were classified via the International Consensus Criteria (ICC). Short-term prognosis, patterns and size of DWI lesions, and involved vascular territories were not significantly different between two groups. Multivariate analysis revealed that extra-cardiac shunt group has a smaller total infarct volume (odds ratio [OR]=0.427, 95% confidence interval [95% CI] 0.228-0.799, p=0.008), and significantly higher bubble grade during resting state and lower grade during the Valsalva maneuver (OR= 0.539, 95% CI 0.438-0.663, p<0.001). Stroke related to an extra-cardiac shunt presented smaller infarct volume, favorable clinical outcomes and characteristic finding on TEE with agitated saline contrast. Further study is needed to confirm whether the extra-cardiac shunt is an independent risk factor. PMID:27653885

  1. 21 CFR 882.5550 - Central nervous system fluid shunt and components.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Central nervous system fluid shunt and components. 882.5550 Section 882.5550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... shunt is a device or combination of devices used to divert fluid from the brain or other part of...

  2. 21 CFR 882.5550 - Central nervous system fluid shunt and components.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Central nervous system fluid shunt and components. 882.5550 Section 882.5550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... shunt is a device or combination of devices used to divert fluid from the brain or other part of...

  3. Sound absorption of a finite micro-perforated panel backed by a shunted loudspeaker.

    PubMed

    Tao, Jiancheng; Jing, Ruixiang; Qiu, Xiaojun

    2014-01-01

    Deep back cavities are usually required for micro-perforated panel (MPP) constructions to achieve good low frequency absorption. To overcome the problem, a close-box loudspeaker with a shunted circuit is proposed to substitute the back wall of the cavity of the MPP constructions to constitute a composite absorber. Based on the equivalent circuit model, the acoustic impedance of the shunted loudspeaker is formulated first, then a prediction model of the sound absorption of the MPP backed by shunted loudspeaker is developed by employing the mode solution of a finite size MPP coupled by an air cavity with an impendence back wall. The MPP absorbs mid to high frequency sound, and with properly adjusted electrical parameters of its shunted circuit, the shunted loudspeaker absorbs low frequency sound, so the composite absorber provides a compact solution to broadband sound control. Numerical simulations and experiments are carried out to validate the model.

  4. An Unusual Complication of Ventriculoperitoneal Shunt: Urinary Bladder Stone Case Report and Literature Review

    PubMed Central

    Xu, Songtao; Sheng, Weixin; Qiu, Yufa; Wang, Jianguo

    2016-01-01

    Introduction: Ventriculoperitoneal (V-P) shunt surgery is the most common technique used for the treatment of hydrocephalus. The migration of ventriculoperitoneal shunt to the bladder is rare. Only two cases have been previously reported in the literature. Case Presentation: We report on a 38-year-old male who had hydrocephalus and V-P shunt for 12 years. Two years ago, he found himself with recurrent urinary tract infections, haematuria and urges incontinence, and then he was diagnosed with bladder perforation and merge stones. The patient had an abdominal operation to cut off and take out the shunt catheter, as well as a transurethral holmium laser lithotripsy. Conclusions: Bladder perforation and stones are rare examples of complications in V-P surgical procedures. Controlling the effective length of the terminal V-P shunt and modifying it appropriately can effectively reduce these complications. PMID:26889393

  5. Multiple Liver Abscesses Associated with Ventriculoperitoneal Shunt Infection: Case Report and Review of the Literature

    PubMed Central

    Yang, Tae Ki

    2013-01-01

    Liver abscess following ventriculoperitoneal (VP) shunting occurs very rarely. We report an unusual case of multiple liver abscesses caused by Staphylococcus capitis in a 50-year-old compromised woman due to a complicating VP shunt infection. We reviewed the nine cases of VP shunt complications reported in the English literature, and speculated that the most likely pathogenetic mechanism in our case is an infected peritoneal tip that migrated to and penetrated the liver, which subsequently caused the formation of multiple liver abscesses. The patient was successfully treated with percutaneous aspiration, drainage of the abscesses, intravenous antibiotics, and shunt revision. Awareness and vigilance of the possibility of liver abscess formation caused by VP shunt infection will help establish an early accurate diagnosis and therapeutic strategy. PMID:24379956

  6. Instantiating a mechatronic valve schedule for a hydrocephalus shunt.

    PubMed

    Momani, Lina; Alkharabsheh, Abdel Rahman; Al-Zuibi, Nayel; Al-Nuaimy, Waleed

    2009-01-01

    Hydrocephalus is caused by blockage or reabsorption difficulty that upsets the natural balance of production and absorption of cerebrospinal fluid in the brain, resulting in a build-up of the fluid in the ventricles of the brain. One of the recent advances in the treatment of hydrocephalus is the invention of a mechatronic valve. The desirability of such valve lies in the potential of having shunt that not only control hydrocephalus but also seeks to treat it. In contrast to current valves, such a valve is regulated based on a time based schedule not on the differential pressure across the valve. Thus the effectiveness of such valve is highly dependant on selecting an appropriate valve schedule that delivers personal dynamic treatment for every individual patient. Providing such a schedule is likely to be one of the obstacles facing the implementation of the mechatronic valve. In this paper, an algorithm is proposed to help in developing such a schedule that dynamically change based on the patients' own intracranial pressure data and a novel figure of merit, thus providing the physician with an easy tool that facilitate the use of the mechatronic valve. The algorithm was implemented in M ATLAB and Simulink. Real ICP data for three hydrocephalus patients (before shunting) were used to test this algorithm and the resulted schedules along with the resulted intracranial pressure data have illustrated the effectiveness of the algorithm in providing schedule that maintain ICP within the normal limits. PMID:19963474

  7. Fabrication and characterization of shunted μ-SQUID

    SciTech Connect

    Kumar, Nikhil; Fournier, T.; Courtois, H.; Gupta, Anjan K.

    2014-04-24

    In order to eliminate hysteresis, we have fabricated and characterized niobium based shunted micron size superconducting quantum interference devices (μ-SQUIDs). We find a wide temperature range where these μ-SQUIDs are non-hysteretic in nature and show a very good I{sub c} vs. B oscillations in hysteretic regime and V vs. B oscillations in non-hysteretic regime. Here we report the characteristics of a shunted- μ-SQUID (Wf38LS72D5). In this device we have achieved a large voltage modulation, in non-hysteretic regime, at various temperatures including such as 1.1 mV at 6.62 K with a transfer function V{sub Φ} = 7.2mV/Φ{sub 0}. The figures within the original article PDF file, as supplied to AIP Publishing, were affected by a PDF-processing error. Consequently, the article re-flowed and pagination increased from 3 to 4 pages. This article was updated on 14 May 2014 to correct the PDF-processing error, with the scientific content remaining unchanged. Readers are advised that the replacement article PDF file contains an additional blank page to preserve the original pagination.

  8. Fabrication and characterization of shunted μ-SQUID

    NASA Astrophysics Data System (ADS)

    Kumar, Nikhil; Fournier, T.; Courtois, H.; Gupta, Anjan K.

    2014-04-01

    In order to eliminate hysteresis, we have fabricated and characterized niobium based shunted micron size superconducting quantum interference devices (μ-SQUIDs). We find a wide temperature range where these μ-SQUIDs are non-hysteretic in nature and show a very good Ic vs. B oscillations in hysteretic regime and V vs. B oscillations in non-hysteretic regime. Here we report the characteristics of a shunted- μ-SQUID (Wf38LS72D5). In this device we have achieved a large voltage modulation, in non-hysteretic regime, at various temperatures including such as 1.1 mV at 6.62 K with a transfer function VΦ = 7.2mV/Φ0. The figures within the original article PDF file, as supplied to AIP Publishing, were affected by a PDF-processing error. Consequently, the article re-flowed and pagination increased from 3 to 4 pages. This article was updated on 14 May 2014 to correct the PDF-processing error, with the scientific content remaining unchanged. Readers are advised that the replacement article PDF file contains an additional blank page to preserve the original pagination.

  9. Isolation and characterization of Salmonella typhimurium glyoxylate shunt mutants.

    PubMed Central

    Wilson, R B; Maloy, S R

    1987-01-01

    Growth of Salmonella typhimurium on acetate as a sole carbon source requires expression of the glyoxylate shunt; however, the genes for the glyoxylate shunt enzymes have not been previously identified in S. typhimurium. In this study, we isolated transposon insertions in the genes for the two unique enzymes of this pathway, aceA (isocitrate lyase) and aceB (malate synthase). The aceA and aceB genes were located at 89.5 min on the S. typhimurium genetic map. Genetic linkage to nearby loci indicated that the relative gene order is purDJ metA aceB aceA. Transposon insertions in aceB were polar on aceA, suggesting that the genes form an operon transcribed from aceB to aceA. Transcriptional regulation of the aceBA operon was studied by constructing mini-Mu d(lac Kan) operon fusions. Analysis of these fusions indicated that expression of the aceBA operon is regulated at the level of transcription; the aceBA genes were induced when acetate was present and repressing carbon sources were absent. Although glucose represses expression of the aceBA operon, repression does not seem to be mediated solely by cyclic AMP-cyclic AMP receptor protein complex. Mutants with altered regulation of the aceBA operon were isolated. PMID:3298210

  10. Nonvascular needle and shunt placements for fetal therapy.

    PubMed Central

    Holzgreve, W; Evans, M I

    1993-01-01

    The nonvascular placement of needles and shunts for the in utero treatment of fetuses with fluid-filled, space-occupying anomalies has been done for about 10 years. The rationale for this approach is to attempt to prevent progressive impairment of organ function or lethal damage by early decompression. Experience has taught us that the key to success in these cases is the exclusion of associated anomalies and the use of appropriate tests to assess the residual organ function at the time of first diagnosis. In fetuses with hydrothorax, shunts can prevent pulmonary hypoplasia, and in those with obstructive uropathy, they can prevent the development of progressive lung hypoplasia and renal damage before a fetus is fully viable. In fetuses with ovarian cysts, prenatal puncture is occasionally indicated, but in those with hydrocephalus, the beneficial effect of prenatal drainage is more controversial. The catheters used for in utero placement have been improved and carry a smaller risk than open fetal surgical procedures. Images PMID:8236975

  11. Laparoscopic Cholecystectomy for Acute Calcular Cholecystitis in a Patient with Ventriculoperitoneal Shunt: A Case Report and Literature Review

    PubMed Central

    Albarrak, Abdullah A.; Khairy, Sami; Ahmed, Alzahrani Mohammed

    2015-01-01

    Management of patients who have ventriculoperitoneal shunt presenting with acute calcular cholecystitis has remained a clinical challenge. In this paper, the hospital course and the follow-up of a patient presenting with acute calcular cholecystitis and ventriculoperitoneal shunt managed with laparoscopic cholecystectomy are presented followed by literature review on the management of acute calcular cholecystitis in patients who have ventriculoperitoneal shunts. PMID:26798543

  12. Hepatic Arterial Infusion Chemotherapy Combined with Venous Embolization in a Patient with Hepatic Metastases with an Arteriovenous Shunt

    SciTech Connect

    Nishiofuku, Hideyuki; Tanaka, Toshihiro; Sakaguchi, Hiroshi; Yamamoto, Kiyosei; Inoue, Masayoshi; Sueyoshi, Satoru; Shinnkai, Takayuki; Hasegawa, Masatoshi; Kichikawa, Kimihiko

    2009-07-15

    We describe herein a patient who had hepatic metastases with an arteriovenous shunt and was treated by hepatic arterial infusion chemotherapy. The arteriovenous shunt was diagnosed by {sup 99m}Tc-macroaggregated albumin scintigraphy and hepatic venous embolization was performed to reduce shunt flow.

  13. Relationship of the location of the ventricular catheter tip and function of the ventriculoperitoneal shunt.

    PubMed

    Yamada, Shoko Merrit; Kitagawa, Ryo; Teramoto, Akira

    2013-01-01

    The long-term maintenance of ventriculoperitoneal (VP) shunt function depends on the correct placement of the catheter tip in the lateral ventricle. The relationship between the location of the ventricular catheter tip and VP shunt function was analyzed in 52 patients. The location of the ventricular catheter tip was classified into one of the following five groups: (i) Group A--superior to the foramen of Monro; (ii) Group B--in the center of the lateral ventricle body; (iii) Group C--in the third ventricle; (iv) Group D--contacting the ventricle wall; and (v) Group E--in the septum pellucidum. VP shunt function was defined as well controlled hydrocephalus when the Evan's ratio of the ventricular size was < 0.3. The VP shunt functioned well in 14 of 52 patients (26.9%), the shunt valve pressure was incorrectly set in 21 (40.4%), and irreversible shunt malfunction was identified in 17 (32.7%). Among the 14 patients with a well-functioning shunt, 13 were in Groups A or B with an odds ratio (OR) of 17.875 (p<0.05). In the 17 irreversible shunt malfunctions, 13 were identified in Groups C, D, or E with an OR of 0.123 (p<0.05). Long term VP shunt function or failure due to irreversible malfunction is directly influenced by the position of the ventricular catheter tip. Ideal points for positioning the ventricular catheter tip are superior to the foramen of Monro and in the center of the lateral ventricle body. Early shunt revision may be required for patients in whom the catheter tip contacts the ventricle wall or is located in the septum pellucidum.

  14. Choice of valve type and poor ventricular catheter placement: Modifiable factors associated with ventriculoperitoneal shunt failure.

    PubMed

    Jeremiah, Kealeboga Josephine; Cherry, Catherine Louise; Wan, Kai Rui; Toy, Jennifer Ah; Wolfe, Rory; Danks, Robert Andrew

    2016-05-01

    Ventriculoperitoneal (VP) shunt insertion is a common neurosurgical procedure, essentially unchanged in recent years, with high revision rates. We aimed to identify potentially modifiable associations with shunt failure. One hundred and forty patients who underwent insertion of a VP shunt from 2005-2009 were followed for 5-9years. Age at shunt insertion ranged from 0 to 91years (median 44, 26% <18years). The main causes of hydrocephalus were congenital (26%), tumour-related (25%), post-haemorrhagic (24%) or normal pressure hydrocephalus (19%). Fifty-eight (42%) patients required ⩾1 shunt revision. Of these, 50 (88%) were for proximal catheter blockage. The median time to first revision was 108days. Early post-operative CT scans were available in 105 patients. Using a formal grading system, catheter placement was considered excellent in 49 (47%) but poor (extraventricular) in 13 (12%). On univariate analysis, younger age, poor ventricular catheter placement and use of a non-programmable valve were associated with shunt failure. On logistic regression modelling, the independent associations with VP shunt failure were poor catheter placement (odds ratio [OR] 4.9, 95% confidence interval [CI] 1.3-18.9, p=0.02) and use of a non-programmable valve (OR 0.4, 95% CI 0.2-1.0, p=0.04). In conclusion, poor catheter placement (revision rate 77%) was found to be the strongest predictor of shunt failure, with no difference in revisions between excellent (43%) and moderate (43%) catheter placement. Avoiding poor placement in those with mild or moderate ventriculomegaly may best reduce VP shunt failures. There may also be an influence of valve choice on VP shunt survival.

  15. Aspirin-induced asthma: clinical aspects, pathogenesis and management.

    PubMed

    Hamad, Ahmed M; Sutcliffe, Amy M; Knox, Alan J

    2004-01-01

    Aspirin (acetylsalicylic acid)-induced asthma (AIA) consists of the clinical triad of asthma, chronic rhinosinusitis with nasal polyps, and precipitation of asthma and rhinitis attacks in response to aspirin and other NSAIDs. The prevalence of the syndrome in the adult asthmatic populations is approximately 4-10%. Respiratory disease in these patients may be aggressive and refractory to treatment. The aetiology of AIA is complex and not fully understood, but most evidence points towards an abnormality of arachidonic acid (AA) metabolism. Cyclo-oxygenase (COX), the rate-limiting enzyme in AA metabolism, exists as two main isoforms. COX-1 is the constitutive enzyme responsible for synthesis of protective prostanoids, whereas COX-2 is induced under inflammatory conditions. A number of theories regarding its pathogenesis have been proposed. The shunting hypothesis proposes that inhibition of COX-1 shunts AA metabolism away from production of protective prostanoids and towards cysteinyl leukotriene (cys-LT) biosynthesis, resulting in bronchoconstriction and increased mucus production. The COX-2 hypothesis proposes that aspirin causes a structural change in COX-2 that results in the generation of products of the lipoxygenase pathway. It is speculated that this may result in the formation of mediators that cause respiratory reactions in AIA. Related studies provide evidence for abnormal regulation of the lipoxygenase pathway, demonstrating elevated levels of cys-LTs in urine, sputum and peripheral blood, before and following aspirin challenge in AIA patients. These studies suggest that cys-LTs are continually and aggressively synthesised before exposure to aspirin and, during aspirin-induced reactions, acceleration of synthesis occurs. A genetic polymorphism of the LTC4S gene has been identified consisting of an A to C transversion 444 nucleotides upstream of the first codon, conferring a relative risk of AIA of 3.89. Furthermore, carriers of the C444 allele demonstrate a

  16. Trans-anal protrusion of ventriculo-peritoneal shunt catheter with silent bowel perforation: report of ten cases in children.

    PubMed

    Ghritlaharey, Rajendra Kumar; Budhwani, K S; Shrivastava, Dhirendra K; Gupta, Gaurav; Kushwaha, Anand Singh; Chanchlani, Roshan; Nanda, Monika

    2007-06-01

    Ventriculo-peritoneal (VP) shunting used in the treatment for hydrocephalus is associated with several complications. Mechanical failure of shunt is the commonest complication of all. Visceral/bowel perforation is an unusual but serious complication of VP shunting. This article reports our experience in the management of ten children who had VP Shunt catheter protrusion from anus. This is a retrospective study of ten patients who had VP shunt catheter protrusion from anus, admitted in the department of paediatric surgery between Jan 1996 and Dec 2005. The records of above ten cases were reviewed for their clinical presentation and management, etc. We had performed 398 VP shunt operations in the last 10 years. Two hundred and seventy one (68.09%) VP Shunts were done for congenital hydrocephalus of which 164 were done in infancy/neonatal period and 107 VP shunts were done in the age group of >1-12 years. One hundred and twenty-seven (31.90%) VP shunt operations were done for patients who had hydrocephalus as a complication following tubercular meningitis (TBM). Out of 398 VP shunts, ten patients (2.51%) had protrusion of the distal end of peritoneal catheter from anus without causing/leading to peritonitis. We observed a 08.29% mortality of all VP shunt operations. Protrusion of VP shunt catheter per rectum can occur without producing peritonitis. Formal exploration and localization of entry of VP shunt catheter in bowel is not mandatory. Mini laparotomy and revision of peritoneal part of shunt can be done if there is no shunt infection.

  17. Chitin synthesis and fungal pathogenesis

    PubMed Central

    Lenardon, Megan D; Munro, Carol A; Gow, Neil AR

    2010-01-01

    Chitin is an essential part of the carbohydrate skeleton of the fungal cell wall and is a molecule that is not represented in humans and other vertebrates. Complex regulatory mechanisms enable chitin to be positioned at specific sites throughout the cell cycle to maintain the overall strength of the wall and enable rapid, life-saving modifications to be made under cell wall stress conditions. Chitin has also recently emerged as a significant player in the activation and attenuation of immune responses to fungi and other chitin-containing parasites. This review summarises latest advances in the analysis of chitin synthesis regulation in the context of fungal pathogenesis. PMID:20561815

  18. Molecular pathogenesis of hereditary hemochromatosis.

    PubMed

    Liu, Jingqi; Pu, Chunwen; Lang, Lang; Qiao, Liang; Abdullahi, Mohanud Abukar Haji; Jiang, Chunmeng

    2016-08-01

    Hereditary hemochromatosis (HH) is an inherited iron overload disorder characterized by normal iron-driven erythropoiesis and abnormal iron metabolism, leading to excess iron deposited in parenchymal cells of liver, heart, and endocrine glands. Iron hormone, hepcidin, plays a critical role in iron homeostasis through interaction with ferroportin (FPN), a major cellular iron exporter. Hepcidin is encoded by hepcidin antimicrobial peptide (HAMP). Mutations in hepcidin and any genes that regulate the biology of hepcidin, including hemochromatosis genes (HFE), Hemojuvelin (HJV), transferring receptor 2 (TFR2) and FPN, result in hemochromatosis. The identification of hepcidin and its role will provide a better understanding for pathogenesis of HH.

  19. [Pathogenesis of atypical femoral fracture].

    PubMed

    Iwata, Ken; Mashiba, Tasuku

    2016-01-01

    We demonstrated microdamage accumulation in the fracture sites in the patients of subtrochanteric atypical femoral fracture with long term bisphosphonate therapy and of incomplete shaft fracture of lateral femoral bowing without bisphosphonate therapy. Based on these findings, pathogenesis of atypical femoral fracture is revealed stress fracture caused by accumulation of microdamages between distal to the lesser trochanter and proximal to the supracondylar flare in the femur in association with severely suppressed bone turnover and/or abnormal lower limb alignment, that causes stress concentration on the lateral side cortex of the femur. PMID:26728533

  20. Biology and pathogenesis of Acanthamoeba.

    PubMed

    Siddiqui, Ruqaiyyah; Khan, Naveed Ahmed

    2012-01-01

    Acanthamoeba is a free-living protist pathogen, capable of causing a blinding keratitis and fatal granulomatous encephalitis. The factors that contribute to Acanthamoeba infections include parasite biology, genetic diversity, environmental spread and host susceptibility, and are highlighted together with potential therapeutic and preventative measures. The use of Acanthamoeba in the study of cellular differentiation mechanisms, motility and phagocytosis, bacterial pathogenesis and evolutionary processes makes it an attractive model organism. There is a significant emphasis on Acanthamoeba as a Trojan horse of other microbes including viral, bacterial, protists and yeast pathogens.

  1. Biology and pathogenesis of Acanthamoeba

    PubMed Central

    2012-01-01

    Acanthamoeba is a free-living protist pathogen, capable of causing a blinding keratitis and fatal granulomatous encephalitis. The factors that contribute to Acanthamoeba infections include parasite biology, genetic diversity, environmental spread and host susceptibility, and are highlighted together with potential therapeutic and preventative measures. The use of Acanthamoeba in the study of cellular differentiation mechanisms, motility and phagocytosis, bacterial pathogenesis and evolutionary processes makes it an attractive model organism. There is a significant emphasis on Acanthamoeba as a Trojan horse of other microbes including viral, bacterial, protists and yeast pathogens. PMID:22229971

  2. Molecular pathogenesis of intrahepatic cholangiocarcinoma.

    PubMed

    Andersen, Jesper B

    2015-02-01

    Cholangiocarcinoma (CCA) is an orphan cancer of the hepatobiliary tract, the incidence of which has increased in the past decade. The molecular pathogenesis of this treatment-refractory disease is poorly understood. Desmoplasia is a key causal feature of CCA; however, a majority of tumors develop with no apparent etiological background. The impact of the stromal compartment on tumor progression as well as resistance to therapy is in vogue, and the epithelial-stromal crosstalk may present a target for novel treatment strategies. As such, the complexity of tumor cellularity and the molecular mechanisms underlying the diversity of growth patterns of this malignancy remain a clinical concern. It is crucial to advance our present understanding of the molecular pathogenesis of CCA to improve current clinical strategies and patient outcome. This will facilitate the delineation of patient subsets and individualization for precision therapies. Many questions persevere as to the evolutionary process and cellular origin of the initial transforming event, the context of intratumoral plasticity and the causal driver action. Next-generation sequencing has begun to underline the persistent alterations, which may be the trigger of acquired drug resistance, and the cause of metastasis and disease recurrence. A complex issue that remains is to account for the heterogeneous pool of "backseat" aberrations, which in chromosomal proximity to the causative variant are likely to influence, for example, drug response. This review explores the recent advances in defining the molecular pathways implicated in the development of this devastating disease and, which present putative clinical strategies. PMID:25174625

  3. Pathogenesis of Varicelloviruses in primates

    PubMed Central

    Ouwendijk, Werner J.D.; Verjans, Georges M.G.M.

    2014-01-01

    Varicelloviruses in primates comprise the prototypic human varicella-zoster virus (VZV) and its non-human primate homologue simian varicella virus (SVV). Both viruses cause varicella as a primary infection, establish latency in ganglionic neurons and reactivate later in life to cause herpes zoster in their respective hosts. VZV is endemic worldwide and although varicella is usually a benign disease in childhood, VZV reactivation is a significant cause of neurological disease in the elderly and in immunocompromised individuals. The pathogenesis of VZV infection remains ill-defined, mostly due to the species restriction of VZV that impedes studies in experimental animal models. SVV infection of non-human primates parallels virological, clinical, pathological and immunological features of human VZV infection, thereby providing an excellent model to study the pathogenesis of varicella and herpes zoster in its natural host. In this review, we discuss recent studies that provided novel insight in both the virus and host factors involved in the three elementary stages of Varicellovirus infection in primates: primary infection, latency and reactivation. PMID:25255989

  4. Molecular Pathogenesis of Neuromyelitis Optica

    PubMed Central

    Bukhari, Wajih; Barnett, Michael H; Prain, Kerri; Broadley, Simon A

    2012-01-01

    Neuromyelitis optica (NMO) is a rare autoimmune disorder, distinct from multiple sclerosis, causing inflammatory lesions in the optic nerves and spinal cord. An autoantibody (NMO IgG) against aquaporin-4 (AQP4), a water channel expressed on astrocytes is thought to be causative. Peripheral production of the antibody is triggered by an unknown process in genetically susceptible individuals. Anti-AQP4 antibody enters the central nervous system (CNS) when the blood brain barrier is made permeable and has high affinity for orthogonal array particles of AQP4. Like other autoimmune diseases, Th17 cells and their effector cytokines (such as interleukin 6) have been implicated in pathogenesis. AQP4 expressing peripheral organs are not affected by NMO IgG, but the antibody causes extensive astrocytic loss in specific regions of the CNS through complement mediated cytotoxicity. Demyelination occurs during the inflammatory process and is probably secondary to oligodendrocyte apoptosis subsequent to loss of trophic support from astrocytes. Ultimately, extensive axonal injury leads to severe disability. Despite rapid advances in the understanding of NMO pathogenesis, unanswered questions remain, particularly with regards to disease mechanisms in NMO IgG seronegative cases. Increasing knowledge of the molecular pathology is leading to improved treatment strategies. PMID:23202933

  5. Pathogenesis and Immunobiology of Brucellosis

    PubMed Central

    de Figueiredo, Paul; Ficht, Thomas A.; Rice-Ficht, Allison; Rossetti, Carlos A.; Adams, L. Garry

    2016-01-01

    This review of Brucella–host interactions and immunobiology discusses recent discoveries as the basis for pathogenesis-informed rationales to prevent or treat brucellosis. Brucella spp., as animal pathogens, cause human brucellosis, a zoonosis that results in worldwide economic losses, human morbidity, and poverty. Although Brucella spp. infect humans as an incidental host, 500,000 new human infections occur annually, and no patient-friendly treatments or approved human vaccines are reported. Brucellae display strong tissue tropism for lymphoreticular and reproductive systems with an intracellular lifestyle that limits exposure to innate and adaptive immune responses, sequesters the organism from the effects of antibiotics, and drives clinical disease manifestations and pathology. Stealthy brucellae exploit strategies to establish infection, including i) evasion of intracellular destruction by restricting fusion of type IV secretion system-dependent Brucella-containing vacuoles with lysosomal compartments, ii) inhibition of apoptosis of infected mononuclear cells, and iii) prevention of dendritic cell maturation, antigen presentation, and activation of naive T cells, pathogenesis lessons that may be informative for other intracellular pathogens. Data sets of next-generation sequences of Brucella and host time-series global expression fused with proteomics and metabolomics data from in vitro and in vivo experiments now inform interactive cellular pathways and gene regulatory networks enabling full-scale systems biology analysis. The newly identified effector proteins of Brucella may represent targets for improved, safer brucellosis vaccines and therapeutics. PMID:25892682

  6. Universality of non-Ohmic shunt leakage in thin-film solar cells

    NASA Astrophysics Data System (ADS)

    Dongaonkar, S.; Servaites, J. D.; Ford, G. M.; Loser, S.; Moore, J.; Gelfand, R. M.; Mohseni, H.; Hillhouse, H. W.; Agrawal, R.; Ratner, M. A.; Marks, T. J.; Lundstrom, M. S.; Alam, M. A.

    2010-12-01

    We compare the dark current-voltage (IV) characteristics of three different thin-film solar cell types: hydrogenated amorphous silicon (a-Si:H) p-i-n cells, organic bulk heterojunction (BHJ) cells, and Cu(In,Ga)Se2 (CIGS) cells. All three device types exhibit a significant shunt leakage current at low forward bias (V <˜0.4) and reverse bias, which cannot be explained by the classical solar cell diode model. This parasitic shunt current exhibits non-Ohmic behavior, as opposed to the traditional constant shunt resistance model for photovoltaics. We show here that this shunt leakage (Ish), across all three solar cell types considered, is characterized by the following common phenomenological features: (a) voltage symmetry about V =0, (b) nonlinear (power law) voltage dependence, and (c) extremely weak temperature dependence. Based on this analysis, we provide a simple method of subtracting this shunt current component from the measured data and discuss its implications on dark IV parameter extraction. We propose a space charge limited (SCL) current model for capturing all these features of the shunt leakage in a consistent framework and discuss possible physical origin of the parasitic paths responsible for this shunt current mechanism.

  7. Portasystemic shunting versus liver transplantation for the Budd-Chiari syndrome.

    PubMed Central

    Bismuth, H; Sherlock, D J

    1991-01-01

    Over 12 years, 22 patients with the Budd-Chiari syndrome were treated surgically. Eighteen underwent a mesenterico-caval shunt (MCS); two, a side-to-side portacaval shunt; one, a mesenterico-atrial shunt (MAS); and one, a liver transplantation (OLT). One patient died after operation from the precipitating condition, and two MCS grafts that thrombosed were restored. All 21 surviving patients remain well, free from ascites, and all shunts are patent after a mean follow-up of 5.6 +/- 1 years, five patients with more than 10 years' follow-up. This long-term survival achieved by portasystemic shunts suggests that they have a major role in the treatment of the Budd-Chiari syndrome. The authors prefer the mesenterico-caval shunt using a jugular graft. This ensures a total portasystemic shunt, avoids subhepatic surgery, and reduces the long-term risk of prosthetic graft thrombosis. The MAS was reserved for cases with complete caval thrombosis. Patients with significant degrees of caval compression were satisfactorily decompressed by MCS. In patients not promptly treated, the disease progresses to cirrhosis, and such patients must be evaluated for transplantation similarly to those with other hepatopathies. Images Fig. 1. Fig. 3. Fig. 4. Fig. 5A and B. PMID:1953111

  8. Ventriculosternal Shunting for the Management of Hydrocephalus: Case Report of A Novel Technique

    PubMed Central

    Hung Pang, Peter Ka; Chan, Kwong Yau; Ching Kwok, John Kwong

    2015-01-01

    BACKGROUND: Conventional cerebrospinal fluid diversion such as ventriculoperitoneal or ventriculoatrial shunting for the management of hydrocephalus is one of the commonest neurosurgical procedures. However, in selected patients, surgical options are limited when relative contraindications for these operations exist. A patient who underwent ventriculosternal shunting, a novel procedure, is presented with durable and successful outcomes. OBJECTIVE: To demonstrate the feasibility, durability, and safety of ventriculosternal shunting for the management of hydrocephalus. METHODS: A patient with end-stage renal failure and heart failure with recurrent pleural effusion suffered from post–subarachnoid hemorrhage communicating hydrocephalus. Because of the need for continuous ambulatory peritoneal dialysis and the risk of introducing excessive cardiac preloading, conventional shunting was relatively contraindicated. Ventriculosternal shunting was performed by adopting the cancellous matrix of the sternum as the anatomic receptacle for intraosseous cerebrospinal fluid absorption. After placement of the ventricular catheter in the usual manner, the distal end was inserted into the sternum. RESULTS: There was demonstrable clinical and radiological improvement in hydrocephalus by ventriculosternal shunting. Cerebrospinal fluid intraosseous absorption by this novel procedure translated into both physical and cognitive recovery. The procedure was tolerable, effective, and durable, with the patient suffering no complications 3 years after the procedure. CONCLUSION: Ventriculosternal shunting for the management of hydrocephalus is a feasible, safe, and durable surgical treatment option for selected patients when conventional procedures are contraindicated. ABBREVIATION: VS, ventriculosternal PMID:26114598

  9. Universality of Non-Ohmic Shunt Leakage in Thin-Film Solar Cells

    SciTech Connect

    Dongaonkar, S.; Servaites, J.D.; Ford, G.M.; Loser, Stephen; Moore, J.; Gelfand, R.M.; Mohseni, H.W.; Agrawal, R.; Ratner, Mark A.; Marks, Tobin J.; Lundstrom, M.S.; Alam, M.A.

    2010-01-01

    We compare the dark current-voltage (IV) characteristics of three different thin-film solar cell types: hydrogenated amorphous silicon (a-Si:H) p-i-n cells, organic bulk heterojunction (BHJ) cells, and Cu(In,Ga)Se2 (CIGS) cells. All three device types exhibit a significant shunt leakage current at low forward bias (V<~0.4) and reverse bias, which cannot be explained by the classical solar cell diode model. This parasitic shunt current exhibits non-Ohmic behavior, as opposed to the traditional constant shunt resistance model for photovoltaics. We show here that this shunt leakage (Ish) , across all three solar cell types considered, is characterized by the following common phenomenological features: (a) voltage symmetry about V=0 , (b) nonlinear (power law) voltage dependence, and (c) extremely weak temperature dependence. Based on this analysis, we provide a simple method of subtracting this shunt current component from the measured data and discuss its implications on dark IV parameter extraction. We propose a space charge limited (SCL) current model for capturing all these features of the shunt leakage in a consistent framework and discuss possible physical origin of the parasitic paths responsible for this shunt current mechanism.

  10. Flexural wave band-gaps in phononic metamaterial beam with hybrid shunting circuits

    NASA Astrophysics Data System (ADS)

    Zhang, Hao; Wen, Ji-Hong; Chen, Sheng-Bing; Wang, Gang; Wen, Xi-Sen

    2015-03-01

    Periodic arrays of hybrid-shunted piezoelectric patches are used to control the band-gaps of phononic metamaterial beams. Passive resistive-inductive (RL) shunting circuits can produce a narrow resonant band-gap (RG), and active negative capacitive (NC) shunting circuits can broaden the Bragg band-gaps (BGs). In this article, active NC shunting circuits and passive resonant RL shunting circuits are connected to the same piezoelectric patches in parallel, which are usually called hybrid shunting circuits, to control the location and the extent of the band-gaps. A super-wide coupled band-gap is generated when the coupling between RG and the BG occurs. The attenuation constant of the infinite periodic structure is predicted by the transfer matrix method, which is compared with the vibration transmittance of a finite periodic structure calculated by the finite element method. Numerical results show that the hybrid-shunting circuits can make the band-gaps wider by appropriately selecting the inductances, negative capacitances, and resistances. Project supported by the National Natural Science Foundation of China (Grant Nos. 51275519 and 51175501).

  11. Controversies: Optic nerve sheath fenestration versus shunt placement for the treatment of idiopathic intracranial hypertension

    PubMed Central

    Spitze, Arielle; Lam, Peter; Al-Zubidi, Nagham; Yalamanchili, Sushma; Lee, Andrew G

    2014-01-01

    Background: Idiopathic intracranial hypertension (IIH) has been increasing in prevalence in the past decade, following the obesity epidemic. When medical treatment fails, surgical treatment options must be considered. However, controversy remains as to which surgical procedure is the preferred surgical option – optic nerve sheath fenestration (ONSF) or cerebrospinal fluid (CSF) shunting – for the long-term treatment of this syndrome. Purpose: To provide a clinical update of the pros and cons of ONSF versus shunt placement for the treatment of IIH. Design: This was a retrospective review of the current literature in the English language indexed in PubMed. Methods: The authors conducted a PubMed search using the following terms: Idiopathic IIH, pseudotumor cerebri, ONSF, CSF shunts, vetriculo-peritoneal shunting, and lumbo-peritoneal shunting. The authors included pertinent and significant original articles, review articles, and case reports, which revealed the new aspects and updates in these topics. Results: The treatment of IIH remains controversial and lacks randomized controlled clinical trial data. Treatment of IIH rests with the determination of the severity of IIH-related visual loss and headache. Conclusion: The decision for ONSF versus shunting is somewhat institution and surgeon dependent. ONSF is preferred for patients with visual symptoms whereas shunting is reserved for patients with headache. There are positive and negative aspects of both procedures, and a prospective, randomized, controlled trial is needed (currently underway). This article will hopefully be helpful in allowing the reader to make a more informed decision until that time. PMID:25449938

  12. Raynaud's phenomenon: new aspects of pathogenesis and the role of nailfold videocapillaroscopy.

    PubMed

    Kuryliszyn-Moskal, Anna; Kita, Jacek; Hryniewicz, Anna

    2015-01-01

    Raynaud's phenomenon (RP) refers to paroxysmal pallor or cyanosis of the digits of the hands or feet and, infrequently, the tips of the nose or ears (acral parts) owing to cold-induced vasoconstriction of the digital arteries, precapillary arterioles, and cutaneous arteriovenous shunts. Raynaud's phenomenon reflects an exaggeration of normal central and local vasomotor responses to cold or emotion. Raynaud's phenomenon has been classified as primary or secondary, depending on whether it occurs as an isolated condition or is associated mainly with a connective tissue disease. Dysregulation of autonomic and sensitive nerve fibers, functional and structural vessel changes, and intravascular alterations can be observed in the pathogenesis of RP. Nailfold videocapillaroscopy (NVC) is the best non-invasive and repetitive diagnostic technique for detecting morpho-functional changes in the microcirculation. Nailfold videocapillaroscopy is accepted in early diagnosis and monitoring of primary and secondary RP.

  13. Shunt Diode Designs in Li/cf Shuttle Batteries

    NASA Technical Reports Server (NTRS)

    Miller, D.; Higgins, R.

    1984-01-01

    Although Li/CF cells and batteries have an excellent safety record, they are included with other battery systems that require additional safety precautions. One precaution suggested is the inclusion of shunt diodes into these batteries. The benefits of this addition are examined. All cells tested at elevated temperatures vent regardless of length of time between being fully discharged and reversed or inclusion of the diode in the system. Cells discharged at ambient temperatures all show a relatively quick reversal, but stabilize at voltages that are high enough that the diodes are not functioning. Cells tested at depressed temperatures reverse the deepest of all cells tested, with the deepest reversal occurring very early in the test and voltages recovering to above -0.60 volts near the end of the tests. Anode limited cells will eliminate the venting during hot reversal.

  14. Electro-clinical follow-up of shunted hydrocephalic children.

    PubMed

    Varfis, G; Berney, J; Beaumanoir, A

    1977-01-01

    In a survey of 29 hydrocephalic children treated by ventriculoatrial shunt (Holter valve) with a follow-up of 4 years, EEG records before the operation and at least once a year thereafter, the authors can support the view that an epileptogenic focus has developed around the place of insertion of the ventricular catheter in 19 cases, leading to epileptic seizures in 17 up to now. Thus the incidence of convulsions in this particular group of patients is 0.59 (17/29), the limits of confidence 95% being 0.39-0.76. The irritative abnormalities occur usually during the second year after the operation and the delay for the onset of clinical seizures is variable. The age at operation seems to influence the occurrence of the epileptogenic scar. The type of hydrocephalus and especially the presence of an associated cerebral focal lesion can be of importance in the development of clinical seizures. PMID:405183

  15. A thiosulfate shunt in the sulfur cycle of marine sediments.

    PubMed

    Jørgensen, B B

    1990-07-13

    The oxidation of sulfide, generated by bacterial sulfate reduction, is a key process in the biogeochemistry of marine sediments, yet the pathways and oxidants are poorly known. By the use of (35)S-tracer studies of the S cycle in marine and freshwater sediments, a novel shunt function of thiosulfate (S(2)O(3)(2-)) was identified. The S(2)O(3)(2-) constituted 68 to 78 percent of the immediate HS(-)-oxidation products and was concurrently (i) reduced back to HS(-), (ii) oxidized to SO(4)(2-), and (iii) disproportionated to HS(-) + SO(4)(2-). The small thiosulfate pool is thus involved in a dynamic HS(-) - S(2)O(3)(2-) cycle in anoxic sediments. The disproportionation of thiosulfate may help account for the large difference in isotopic composition ((34)S/(32)S) of sulfate and sulfides in sediments and sedimentary rocks.

  16. The effects of dobutamine and dopamine on intrapulmonary shunt and gas exchange in healthy humans

    PubMed Central

    Bryan, Tracey L.; van Diepen, Sean; Bhutani, Mohit; Shanks, Miriam; Welsh, Robert C.

    2012-01-01

    The development of intrapulmonary shunts with increased cardiac output during exercise in healthy humans has been reported in several recent studies, but mechanisms governing their recruitment remain unclear. Dobutamine and dopamine are inotropes commonly used to augment cardiac output; however, both can increase venous admixture/shunt fraction (Qs/Qt). It is possible that, as with exercise, intrapulmonary shunts are recruited with increased cardiac output during dobutamine and/or dopamine infusion that may contribute to the observed increase in Qs/Qt. The purpose of this study was to examine how dobutamine and dopamine affect intrapulmonary shunt and gas exchange. Nine resting healthy subjects received serial infusions of dobutamine and dopamine at incremental doses under normoxic and hyperoxic (inspired O2 fraction = 1.0) conditions. At each step, alveolar-to-arterial Po2 difference (A-aDo2) and Qs/Qt were calculated from arterial blood gas samples, intrapulmonary shunt was evaluated using contrast echocardiography, and cardiac output was calculated by Doppler echocardiography. Both dobutamine and dopamine increased cardiac output and Qs/Qt. Intrapulmonary shunt developed in most subjects with both drugs and paralleled the increase in Qs/Qt. A-aDo2 was unchanged due to a concurrent rise in mixed venous oxygen content. Hyperoxia consistently eliminated intrapulmonary shunt. These findings contribute to our present understanding of the mechanisms governing recruitment of these intrapulmonary shunts as well as their impact on gas exchange. In addition, given the deleterious effect on Qs/Qt and the risk of neurological complications with intrapulmonary shunts, these findings could have important implications for use of dobutamine and dopamine in the clinical setting. PMID:22700799

  17. A single-incision laparoscopic technique for retrieval and replacement of disconnected ventriculoperitoneal shunt tubing found in the peritoneum.

    PubMed

    Jackson, C C; Chwals, W J; Frim, D M

    2002-04-01

    A 7-year-old girl presented with signs and symptoms of increased intracranial pressure 2 years after insertion of a ventriculoperitoneal (VP) shunt. Evaluation revealed disconnection of the distal shunt catheter and migration into the peritoneal cavity. A single-incision laparoscopic procedure was performed to locate and remove the disconnected shunt tubing, and the new shunt catheter was inserted through the laparoscopic port site. Laparoscopy is being used more frequently for evaluation and repair of distal VP shunt malfunctions, but generally still requires multiple incisions for port placement and insertion of the new shunt catheter. The single-incision technique used here is technically feasible, allows excellent visualization of the peritoneal cavity and does not require any incisions beyond the previous one used for initial shunt insertion.

  18. Severity of the ductal shunt: a comparison of different markers

    PubMed Central

    El Hajjar, M; Vaksmann, G; Rakza, T; Kongolo, G; Storme, L

    2005-01-01

    Background: When the ductus arteriosus (DA) is patent, the ductal shunt is proportional to the ratio of left ventricular output (LVO) to systemic blood flow. Systemic blood flow can be estimated by measuring flow in the superior vena cava (SVC). Objective: To re-evaluate the accuracy of standard echocardiographic markers of patent ductus arteriosus (PDA) using LVO/SVC flow ratio. Methods: Prospective study. Preterm infants of 24–30 weeks gestational age and postnatal age less than 48 hours. The following echocardiographic criteria were measured: left atrial to aortic root ratio (LA/Ao); DA diameter by B mode and colour Doppler; mean and end diastolic flow velocity of the left pulmonary artery (LPA); LVO; SVC flow. Results: Twenty three preterm infants were enrolled (median gestational age 28 weeks (range 24–30), median birth weight 840 g (500–1440)). The DA was closed in eight (mean (SD) LVO/SVC 2.4 (0.3)) and open in 15 (mean (SD) LVO/SVC 4.5 (0.6)). An LA/Ao ratio ⩾1.4, a DA diameter ⩾1.4 mm/kg, and a mean and end diastolic flow velocity of LPA respectively ⩾0.42 and ⩾0.20 m/s identified an LVO/SVC ⩾4 with a sensitivity and a specificity above 90%. Conclusion: This study indicates that LA/Ao ratio, DA diameter, and mean and end diastolic flow velocity of the LPA are accurate markers of PDA. These standard echocardiographic variables are easy to measure and need less skill and resources than direct measurements of ductal shunt. PMID:16113155

  19. Intractable seizures associated with proximal migration of a ventriculoperitoneal shunt. Case report.

    PubMed

    Yamazaki, Tomoya; Shimizu, Satoru; Sagiuchi, Takao; Iwasaki, Toshiyuki; Utsuki, Satoshi; Suzuki, Sachio; Fujii, Kiyotaka

    2005-11-01

    A 6-year-old girl, who had received a ventriculoperitoneal (VP) shunt using the Codman-Hakim programmable valve system at age 3 months, presented with intractable seizures. Neuroimaging studies showed migration of the proximal part of the system, including the prechamber, into the cranium through the right frontal burr hole. Electroencephalography showed spike-and-wave complexes in the right hemisphere including the site of the migration. The ictus was resolved following revision surgery. The clinical findings suggested the seizures were due to irritation of the brain parenchyma by the migrated system. Proximal migration of a VP shunt may cause both shunt failure and additional focal symptoms.

  20. An interesting case of screen-detected breast cancer encasing a ventriculoperitoneal shunt.

    PubMed

    Jain, Yogesh Kumar; Kokan, Jalal S

    2013-01-01

    A 67-year-old woman was diagnosed with a breast cancer via screening encasing the ventriculoperitoneal shunt. Triple assessment including MRI scan of the breast confirmed the presence of a breast mass and the tubing of the ventriculoperitoneal shunt was running directly through the mass. She underwent wide local excision of the breast cancer as well as rerouting of VP shunt as a joint procedure with the neurosurgery team and recovered uneventfully. This is a very rare and an interesting case and required management involving a different specialty.

  1. Failure of peritoneal and gallbladder shunts in a child with craniopharyngioma.

    PubMed

    Woodfield, Julie; Magdum, Shailendra

    2013-09-01

    A 1-year-old girl with craniopharyngioma required external drainage of 40-50 mL/h of cerebrospinal fluid (CSF) after biopsy and cyst fenestration. She developed CSF ascites following insertion of a ventriculoperitoneal (VP) shunt and a distended painful gallbladder following ventriculogallbladder shunt insertion. Revision to a ventriculoatrial shunt was required. This is the first time a craniopharyngioma has been reported to cause increased CSF production. The potential mechanisms of CSF overproduction and the difficulties managing the large volume of CSF in a young child are discussed.

  2. Severe Juxtahepatic Venous Injury: Survival after Prolonged Hepatic Vascular Isolation Without Shunting

    PubMed Central

    Worthley, C. S.; Terblanche, J.

    1990-01-01

    Survival following major juxtahepatic venous injury is rare in blunt liver trauma despite the use of intracaval shunting. Prolonged liver arterial inflow control, total hepatic venous isolation and lobectomy without shunting was used in a patient to repair a combined vena caval and hepatic venous injury after blunt liver injury. An extended period of normothermic hepatic ischemia was tolerated. Early recognition of retrohepatic venous injury and temporary liver packing to control bleeding and correct hypovolemia are essential before caval occlusion. Hepatic vascular isolation without shunting is an effective simple alternative technique allowing major venous repair in complex liver trauma. PMID:2090188

  3. Testing of cerebrospinal compensatory reserve in shunted and non-shunted patients: a guide to interpretation based on an observational study.

    PubMed Central

    Czosnyka, M; Whitehouse, H; Smielewski, P; Simac, S; Pickard, J D

    1996-01-01

    OBJECTIVE--To design a computerised infusion test to compensate for the disadvantages of Katzman's lumbar infusion method: inadequate accuracy of estimation of the resistance to cerebrospinal fluid outflow and poor predictive value in normal pressure hydrocephalus. METHODS--Accuracy was improved by intracranial pressure signal processing and model analysis for measurement of cerebrospinal compensatory variable. These include the CSF outflow resistance, brain compliance, pressure-volume index, estimated sagittal sinus pressure, CSF formation rate, and other variables. Infusion may be made into the lumbar space, ventricles, or, when assessing shunt function in vivo, the shunt chamber. RESULTS AND CONCLUSIONS--The computerised test has been used for five years in a multicentre study in 350 hydrocephalic patients of various ages, aetiologies, and states of cerebrospinal compensation. The principles of using the test to characterise different types of CSF circulatory disorders in patients presenting with ventricular dilatation, including brain atrophy and normal and high pressure hydrocephalus, are presented and illustrated. Previous studies showed a positive correlation between cerebrospinal compensatory variables and the results of shunting, but such a prediction remains difficult in idiopathic normal pressure hydrocephalus, particularly in elderly patients. The technique is helpful in the assessment of shunt malfunction, including posture-related overdrainage, over-drainage related to the nocturnal B wave activity, and proximal or distal shunt obstruction. The appendix presents an introduction of the mathematical modelling of CSF pressure volume-compensation included in computerised infusion test software. Images PMID:8778261

  4. Molecular Pathogenesis of Hepatocellular Carcinoma

    PubMed Central

    Ho, Daniel Wai-Hung; Lo, Regina Cheuk-Lam; Chan, Lo-Kong; Ng, Irene Oi-Lin

    2016-01-01

    The pathogenesis of hepatocellular carcinoma (HCC) is a multistep process involving the progressive accumulation of molecular alterations pinpointing different molecular and cellular events. The next-generation sequencing technology is facilitating the global and systematic evaluation of molecular landscapes in HCC. There is emerging evidence supporting the importance of cancer metabolism and tumor microenvironment in providing a favorable and supportive niche to expedite HCC development. Moreover, recent studies have identified distinct surface markers of cancer stem cell (CSC) in HCC, and they also put forward the profound involvement of altered signaling pathways and epigenetic modifications in CSCs, in addition to the concomitant drug resistance and metastasis. Taken together, multiple key genetic and non-genetic factors, as well as liver CSCs, result in the development and progression of HCC. PMID:27781201

  5. Pathogenesis of Brain Arteriovenous Malformations

    PubMed Central

    KOMIYAMA, Masaki

    2016-01-01

    Brain arteriovenous malformations (bAVMs) represent a high risk of intracranial hemorrhages, which are substantial causes of morbidity and mortality of bAVMs, especially in children and young adults. Although a variety of factors leading to hemorrhages of bAVMs are investigated extensively, their pathogenesis is still not well elucidated. The author has reviewed the updated data of genetic aspects of bAVMs, especially focusing on clinical and experimental knowledge from hereditary hemorrhagic telangiectasia, which is the representative genetic disease presenting with bAVMs caused by loss-of-function in one of the two genes: endoglin and activin receptor-like kinase 1. This knowledge may allow us to infer the pathogensis of sporadic bAVMs and in the development of new medical therapies for them. PMID:27076383

  6. Raynaud's phenomenon: pathogenesis and management.

    PubMed

    Bakst, Richard; Merola, Joseph F; Franks, Andrew G; Sanchez, Miguel

    2008-10-01

    Raynaud's phenomenon is a common clinical disorder for which patients frequently seek the expertise and care of dermatologists. It is manifested by recurrent vasospasm of the fingers and toes, often associated with exposure to cold temperature or emotional stress. The phenomenon is named after Maurice Raynaud, who, as a medical student, defined the first case in 1862 as episodic, symmetric, acral vasospasm characterized by pallor, cyanosis, suffusion, and a sense of fullness or tautness, which may be painful. Despite more than 140 years of research, the pathophysiology of Raynaud's phenomenon continues to elude investigators. Accordingly, although many pharmacologic treatments have been reported, there is still no cure or gold standard therapy. Further, response to treatment varies and is difficult to predict. Recently, there has been renewed interest in finding the pathogenetic mechanisms of Raynaud's phenomenon, an effort that has led to more potential targeted therapeutics. The purpose of this review is to discuss recent breakthroughs in the pathogenesis and treatment of Raynaud's phenomenon.

  7. Neisseria meningitidis: pathogenesis and immunity.

    PubMed

    Pizza, Mariagrazia; Rappuoli, Rino

    2015-02-01

    The recent advances in cellular microbiology, genomics, and immunology has opened new horizons in the understanding of meningococcal pathogenesis and in the definition of new prophylactic intervention. It is now clear that Neissera meningitidis has evolved a number of surface structures to mediate interaction with host cells and a number of mechanisms to subvert the immune system and escape complement-mediated killing. In this review we report the more recent findings on meningococcal adhesion and on the bacteria-complement interaction highlighting the redundancy of these mechanisms. An effective vaccine against meningococcus B, based on multiple antigens with different function, has been recently licensed. The antibodies induced by the 4CMenB vaccine could mediate bacterial killing by activating directly the classical complement pathway or, indirectly, by preventing binding of fH on the bacterial surface and interfering with colonization.

  8. Ventriculoperitoneal shunt disconnection associated with spontaneous knot formation in the peritoneal catheter.

    PubMed

    Lo, William B; Ramirez, Roberto; Rodrigues, Desiderio; Solanki, Guirish A

    2013-01-01

    A 10-year-old girl underwent distal ventriculoperitoneal (VP) shunt revision 3 weeks earlier and developed further shunt malfunction. During the current shunt revision, a disconnection at the straight connector site in the cervical subcutaneous tissue was confirmed and a knot was identified in the peritoneal catheter. Postoperatively, the patient made a rapid neurological recovery and was discharged 48 h later. This is the first case of VP shunt disconnection associated with a spontaneous distal knot formation. The likely mechanism was that the spontaneously formed knot acted as an anchor at the peritoneal wall, preventing free relative movement of the distal catheter. The resultant tension led to failure at the weakest point of the system, resulting in a disconnection at the proximal straight connector site.

  9. Optimizing the Shunting Schedule of Electric Multiple Units Depot Using an Enhanced Particle Swarm Optimization Algorithm.

    PubMed

    Wang, Jiaxi; Lin, Boliang; Jin, Junchen

    2016-01-01

    The shunting schedule of electric multiple units depot (SSED) is one of the essential plans for high-speed train maintenance activities. This paper presents a 0-1 programming model to address the problem of determining an optimal SSED through automatic computing. The objective of the model is to minimize the number of shunting movements and the constraints include track occupation conflicts, shunting routes conflicts, time durations of maintenance processes, and shunting running time. An enhanced particle swarm optimization (EPSO) algorithm is proposed to solve the optimization problem. Finally, an empirical study from Shanghai South EMU Depot is carried out to illustrate the model and EPSO algorithm. The optimization results indicate that the proposed method is valid for the SSED problem and that the EPSO algorithm outperforms the traditional PSO algorithm on the aspect of optimality. PMID:27436998

  10. Design and test of a novel isolator with negative resistance electromagnetic shunt damping

    NASA Astrophysics Data System (ADS)

    Yan, Bo; Zhang, Xinong; Niu, Hongpan

    2012-03-01

    This paper proposes a negative resistance electromagnetic shunt damping vibration isolator and investigates the effectiveness of the isolator. The isolator consists of a shunt circuit and a pair of electromagnet and permanent magnets that are pasted onto a box-shaped spring. A kind of negative resistance shunt impedance is proposed to cancel the inherent resistance of the electromagnet. The electromechanical coupling coefficient and the electromagnetic damping force calculation formula are obtained by Biot-Savart’s law and Ampère’s law, respectively. A single degree of freedom system is employed to verify the performance of the proposed isolator. The governing equation is established. The performance of the proposed isolator under a half-cycle sine pulse is investigated and discussed. Experiments were carried out and the results agreed well with the numerical predictions. Both the results demonstrate that the negative resistance electromagnetic shunt damping vibration isolator could suppress vibration transmitted to the structure effectively.

  11. Laparoscopic Cholecystectomy for a Patient with a Lumboperitoneal Shunt: A Rare Case.

    PubMed

    Rumba, Roberts; Vanags, Andrejs; Strumfa, Ilze; Pupkevics, Andrejs; Pavars, Maris

    2016-01-01

    A rare factor that can complicate the perioperative course of laparoscopic cholecystectomy is previous placement of a lumboperitoneal (LP) shunt. Thus far, only two articles describing this situation have been published. Here, we report on a 41-year-old female patient with gallstone disease and a LP shunt placement in the preceding year due to idiopathic intracranial hypertension. It is a syndrome of increased intracranial pressure without any known cause that mainly affects young obese women. The patient was operated upon using standard port placement and peritoneal insufflation. The postoperative period was uneventful and the patient was discharged shortly after the procedure. Due to the increasing incidence and prevalence of obesity, the number of general surgical patients with a LP shunt will likely increase. Based on our experience and evidence in the literature, we conclude that performing a laparoscopy for a patient with a LP shunt is safe. PMID:27452939

  12. Optimizing the Shunting Schedule of Electric Multiple Units Depot Using an Enhanced Particle Swarm Optimization Algorithm

    PubMed Central

    Jin, Junchen

    2016-01-01

    The shunting schedule of electric multiple units depot (SSED) is one of the essential plans for high-speed train maintenance activities. This paper presents a 0-1 programming model to address the problem of determining an optimal SSED through automatic computing. The objective of the model is to minimize the number of shunting movements and the constraints include track occupation conflicts, shunting routes conflicts, time durations of maintenance processes, and shunting running time. An enhanced particle swarm optimization (EPSO) algorithm is proposed to solve the optimization problem. Finally, an empirical study from Shanghai South EMU Depot is carried out to illustrate the model and EPSO algorithm. The optimization results indicate that the proposed method is valid for the SSED problem and that the EPSO algorithm outperforms the traditional PSO algorithm on the aspect of optimality. PMID:27436998

  13. Laparoscopic Cholecystectomy for a Patient with a Lumboperitoneal Shunt: A Rare Case.

    PubMed

    Rumba, Roberts; Vanags, Andrejs; Strumfa, Ilze; Pupkevics, Andrejs; Pavars, Maris

    2016-01-01

    A rare factor that can complicate the perioperative course of laparoscopic cholecystectomy is previous placement of a lumboperitoneal (LP) shunt. Thus far, only two articles describing this situation have been published. Here, we report on a 41-year-old female patient with gallstone disease and a LP shunt placement in the preceding year due to idiopathic intracranial hypertension. It is a syndrome of increased intracranial pressure without any known cause that mainly affects young obese women. The patient was operated upon using standard port placement and peritoneal insufflation. The postoperative period was uneventful and the patient was discharged shortly after the procedure. Due to the increasing incidence and prevalence of obesity, the number of general surgical patients with a LP shunt will likely increase. Based on our experience and evidence in the literature, we conclude that performing a laparoscopy for a patient with a LP shunt is safe.

  14. Anal extrusion of migrated ventriculo-peritoneal shunt catheter: An unusual complication and review of literature

    PubMed Central

    Sarkari, Avijit; Borkar, Sachin A.; Mahapatra, A. K.

    2016-01-01

    Authors present an unusual case of anal extrusion of peritoneal end of ventriculo-peritoneal shunt in a 2-year-old male child. Pertinent literature is reviewed regarding this rare complication of a very commonly performed neurosurgical procedure.

  15. Unusual Gross Pneumocephalus and Pneumoperitoneum after VP Shunt Surgery: A Case Report.

    PubMed

    A, Khanolkar; Yk, Sarin

    2015-01-01

    We report an unusual case where a two-month infant developed a simultaneous and spontaneous pneumocephalus and gross pneumoperitoneum along with progressive surgical emphysema after VP shunt procedure.

  16. Ischemic stroke patients with active malignancy or extracardiac shunts are more likely to have a right-to-left shunt found by TCD than echocardiogram.

    PubMed

    de Havenon, Adam; Moore, Anne; Sultan-Qurraie, Ali; Majersik, Jennifer J; Stoddard, Greg; Tirschwell, David

    2015-10-01

    Although the association between patent foramen ovale and ischemic stroke is controversial, the evaluation for a right-to-left shunt remains part of the standard workup for cryptogenic stroke. Transthoracic and transesophageal echocardiogram (TTE and TEE) are the screening test and gold standard to evaluate for right-to-left shunt, respectively. Studies comparing TTE or TEE to transcranial Doppler (TCD) have shown that 15-25 % of patients test positive for right-to-left shunt on TCD but are negative on TTE or TEE. We sought to further explore this phenomenon in patients with recent ischemic stroke. Between 2011 and 2013, 109 ischemic stroke patients had both a TCD and TTE or TEE bubble study. We abstracted 12 comorbid medical conditions and stroke subtype according to the TOAST classification. The majority of TCD and TTE or TEE showed agreement on right-to-left shunt status (80/109, 73 %). Two percent (2/109) of patients were negative on TCD and positive on TTE or TEE, while 25 % (27/109) had a positive TCD and negative TTE or TEE (TCD+Echo-). The TCD+Echo- patients were more likely to have active malignancy and the delayed arrival of contrast bubbles than the remainder of the cohort (15 vs. 2 %, p = 0.032; 51 vs. 18 %, p = 0.001). Our results confirm previous reports that TCD is superior to echocardiography in the detection of right-to-left shunt. The TCD+Echo- patients were more likely to have active malignancy and findings suggestive of an extracardiac shunt. These results could lead to more comprehensive evaluation for occult malignancy or a pulmonary arteriovenous malformation, both potentially treatable etiologies of ischemic stroke.

  17. Impact of shunt capacitor banks on substation surge environment and surge arrester applications

    SciTech Connect

    1996-10-01

    The introduction of high voltage shunt capacitor banks on a power system can result in a number of overvoltage problems that tend to be associated with capacitor switching. Proper application of surge arresters near a shunt capacitor bank requires careful analysis of the power system, the switching devices and their arrangements, the insulation level of nearby equipment, the type of grounding, and the arrester energy dissipation duty.

  18. Bilateral Papilledema as the First Sign of Ventriculoperitoneal Shunt Dysfunction§

    PubMed Central

    Serna-Ojeda, Juan Carlos; Aguirre-Mireles, Montserrat; Camargo-Suarez, Mayra Fabiola

    2015-01-01

    A 12 year-old girl patient with a history of ventriculoperitoneal shunt placement at the age of 6 months presented with progressive bilateral decrease in visual acuity. Ophthalmologic examination was consistent with bilateral papilledema. No other systemic manifestations of increased intracranial pressure were evident and laboratory work-up excluded other inflammatory or infectious processes. We present here an interesting case of a patient with ophthalmologic manifestations as the initial finding of ventriculoperitoneal shunt dysfunction. PMID:25834657

  19. Experimental Percutaneous Extrahepatic Portacaval Shunt Creation by Transjugular Approach in Swine

    SciTech Connect

    Seong, Chang Kyu; Pavcnik, Dusan Uchida, Barry T.; Anai, Hiroshi; Timmermans, Hans; Niyyati, Mahtab; Corless, Christopher L.; Correa, Luiz O.; Keller, Frederick S.; Roesch, Josef

    2005-06-15

    The purpose of the study was to evaluate the feasibility of the creation of a percutaneous extrahepatic portacaval shunt (PEPS) in swine by a transjugular approach and to find a suitable stent-graft to use in PEPS. In 12 swine, the extrahepatic portal vein (PV) was entered from the inferior vena cava (IVC) by a needle system introduced from the transjugular approach. A catheter introduced through the transhepatic approach served as a target. Five types of stent-graft consisting of homemade Z stents and a polytetrafluoethylene cover were explored for PEPS creation. Eight animals had follow-up venograms up to 6 weeks or until the shunt became severely stenotic. Gross and histologic examinations were performed after the final follow-up venography. The PV punctures and stent-graft placement were difficult, but the PEPS was established in all animals. In four animals, the stent-graft failed to adequately cover the tract, causing severe hemorrhage. Only two shunts remained patent up to 6 weeks. The other shunts exhibited severe stenosis or occlusion. At gross examination, all shunts traversed the liver parenchyma of the caudate lobe surrounding the IVC. The extravascular PEPS portion was 4 mm to 2 cm long. All shunts entered the PV close to the splenomesenteric junction and exhibited neointimal formation. Shunt stenoses were caused by neointimal hyperplasia and occlusions by a superimposed thrombus. PEPS can be created by the transjugular approach in swine, but only the PV shunt entrance is extrahepatic. None of the tested rigid stent-grafts were suitable for PEPS creation. A short flexible stent-graft with flanged ends is suggested for further exploration.

  20. Superconducting FCL using a combined inducted magnetic field trigger and shunt coil

    DOEpatents

    Tekletsadik, Kasegn D.

    2007-10-16

    A single trigger/shunt coil is utilized for combined induced magnetic field triggering and shunt impedance. The single coil connected in parallel with the high temperature superconducting element, is designed to generate a circulating current in the parallel circuit during normal operation to aid triggering the high temperature superconducting element to quench in the event of a fault. The circulating current is generated by an induced voltage in the coil, when the system current flows through the high temperature superconducting element.

  1. Robotic-assisted hysterectomy in a patient with a ventriculoperitoneal shunt.

    PubMed

    Bush, Stephen H; Greg Heywood, S; Calhoun, Byron C

    2011-12-01

    There are several articles in the literature reporting laparoscopic surgery in patients with ventriculoperitoneal shunts (VPSs). Although the majority of these conclude that a pneumoperitoneum in these patients is safe, there are other reports indicating possible complications of the insufflation. This is the first known report of a robotic-assisted hysterectomy performed on a patient with a VPS and the management of the shunt during the procedure. PMID:27628120

  2. Optimal Surgical Management Using a Classic Blalock-Taussig Shunt for an Infected Pseudoaneurysm After a Modified Blalock-Taussig Shunt Procedure.

    PubMed

    Okada, Noritaka; Murayama, Hiroomi; Hasegawa, Hiroki

    2016-05-01

    We present 2 cases of a 3-month-old girl and boy who were diagnosed with an infected pseudoaneurysm 2 months after undergoing left-sided modified Blalock-Taussig shunt (mBTS) operations for pulmonary atresia. Because the shunts in both cases were nearly obstructed, they underwent a 2-stage surgical approach: classic BTS operations through a right thoracotomy to establish sufficient pulmonary flow and infected graft removal through a median sternotomy after close observation of the state of the aneurysms. By utilizing autologous tissue from a different thoracic entry, both patients were successfully managed and recovered without any recurrence of infection. PMID:27106441

  3. CSF shunt infections: a fifteen-year experience with emphasis on management and outcome.

    PubMed

    Morissette, I; Gourdeau, M; Francoeur, J

    1993-05-01

    A retrospective study of patients with cerebrospinal fluid shunt infections was undertaken from 1975 to 1989 in a university hospital. The data were analyzed with emphasis on the choice of treatment and outcome. There were 44 infectious episodes in 38 patients for an overall rate of 2.6%, including 30 ventriculoperitoneal, 11 ventriculoatrial and 3 lumboperitoneal shunts. The most frequently isolated pathogens were staphylococci in 61% of the cases followed by gram-negative bacilli in 25%. Different modalities of treatment were used: support (2), intravenous antibiotics alone (6), intravenous antibiotics and shunt revision (3), intravenous antibiotics and shunt removal with or without prior externalization of the distal end (33: 13 + 20). The cure rate was 94% (31/33) with this last modality of treatment. Only 3 patients received intraventricular antibiotics. All deaths occurred in patients treated with support only (2) or with antibiotics alone (1). Four of the six recurrent episodes occurred in patients treated with antibiotics alone (2) or with a shunt revision (2). We conclude that carefully chosen intravenous antibiotics combined with shunt removal preceded or not by externalization of the distal end as an alternative therapy to repeated ventricular taps or insertion of an external ventricular drainage device is an appropriate therapy.

  4. Spontaneous bacterial peritonitis causing Serratia marcescens and Proteus mirabilis ventriculoperitoneal shunt infection. Case report.

    PubMed

    Tumialán, Luis M; Lin, Franklin; Gupta, Sanjay K

    2006-08-01

    The authors report their experience treating a polymicrobial ventriculoperitoneal (VP) shunt infection in a developmentally delayed 21-year-old woman. Cerebrospinal fluid (CSF) cultures grew Serratia marcescens and Proteus mirabilis. On admission and throughout her hospitalization, results of physical examination of her abdomen were normal, and radiographic studies showed no evidence of bowel perforation or pseudocyst formation. Contrast-enhanced computed tomography of the abdomen revealed a small fluid collection. After a course of intravenous gentamicin and imipenem with cilastatin in conjunction with intrathecal gentamicin, the infection was resolved and the VP shunt was reimplanted. Although VP shunt infections are not uncommon, S. marcescens as a causative agent is exceedingly rare and potentially devastating. Only two previous cases of S. marcescens shunt infection have been reported in the literature. Authors reporting on S. marcescens infections in the central nervous system (CNS) have observed significant morbidity and death. Although more common, the presence of P. mirabilis in the CSF is still rare and highly suggestive of bowel perforation, which was absent in this patient. Spontaneous bacterial peritonitis was the likely source from which these bacteria gained entrance into the VP shunt system, eventually causing ventriculitis in this patient. The authors conclude that in light of the high morbidity associated with S. marcescens infection of the CNS, intrathecal administration of gentamicin should be strongly considered as part of first-line therapy for S. marcescens infections in VP shunts.

  5. Mechanism for measurement of flow rate of cerebrospinal fluid in hydrocephalus shunts.

    PubMed

    Rajasekaran, Sathish; Kovar, Spencer; Qu, Peng; Inwald, David; Williams, Evan; Qu, Hongwei; Zakalik, Karol

    2014-01-01

    The measurement of the flow rate of cerebrospinal fluid (CSF) or existence of CSF flow inside the shunt tube after shunt implant have been reported as tedious process for both patients and doctors; this paper outlines a potential in vitro flow rate measurement method for CSF in the hydrocephalus shunt. The use of implantable titanium elements in the shunt has been proposed to allow for an accurate temperature measurement along the shunt for prediction of CSF flow rate. The CSF flow velocity can be deduced by decoupling the thermal transfer in the measured differential time at a pair of measurement spots of the titanium elements. Finite element analyses on the fluidic and thermal behaviors of the shunt system have been conducted. Preliminary bench-top measurements on a simulated system have been carried out. The measured flow rates, ranging from 0.5 mm/sec to 1.0 mm/sec, which is clinically practical, demonstrate good agreements with the simulation results.

  6. Hydrocephalus and Ventriculoperitoneal Shunts: Modes of Failure and Opportunities for Improvement.

    PubMed

    Jorgensen, Julianne; Williams, Corin; Sarang-Sieminski, Alisha

    2016-01-01

    Between 0.5 and 4 of every 1000 children are born with hydrocephalus. Hydrocephalus is an over-accumulation of cerebrospinal fluid (CSF) in the ventricles of the brain, which can affect cognitive function, vision, appetite, and cranial nerve function. Left untreated, hydrocephalus can result in death. The current treatment for hydrocephalus uses ventriculoperitoneal (VP) shunts with valves to redirect CSF from the ventricles into the peritoneum. Shunt technology is limited by a number of complications, which include infection after implantation, shunt obstruction due to clot formation or catheter obstruction by scar tissue or choroid plexus, disconnection and tubing migration, and overdrainage or underdrainage of CSF due to valve malfunction. While modifications to surgical procedures and shunt design have been introduced, only modest improvements in outcomes have been observed. Here we provide an overview of hydrocephalus, VP shunts, and their modes of failure, and we identify numerous areas of opportunity for biomedical engineers and physicians to collaborate to improve the performance of VP shunts.

  7. Standard Trabeculectomy and Ex-PRESS Miniature Glaucoma Shunt: A Comparative Study and Literature Review

    PubMed Central

    Zunz, Eran; Tzur, Rotem; Kurtz, Shimon; Shemesh, Gabi

    2015-01-01

    Purpose: The aim of this study was to compare the efficacy and safety between standard trabeculectomy and the Ex-PRESS shunt implantation. Methods: A retrospective review of the records of 100 eyes of 100 patients who underwent trabeculectomy or Ex-PRESS shunt implantation between July 2010 and June 2012 was conducted. Of these, 61 (61%) eyes underwent trabeculectomy and 39 (39%) eyes underwent Ex-PRESS shunt implantation. Demographic information, glaucoma type, surgical details, preoperative, and postoperative data including intraocular pressure (IOP), number of medications, reoperation, and occurrence of any complications were recorded. Results: No differences in IOP reduction or number of postoperative IOP-lowering medications were demonstrated between the 2 procedures. Success rates were 86.9% for trabeculectomy and 84.6% for Ex-PRESS shunt. Rates of failure and hypotony were not significantly different between the groups. No parameter was correlated with success or failure of any procedure. Conclusions: Standard trabeculectomy and Ex-PRESS shunt have similar efficacy and safety profiles. As the Ex-PRESS shunt is considerably more expensive, its use may be unjustified, especially as a primary procedure. PMID:24633088

  8. Mechanism for measurement of flow rate of cerebrospinal fluid in hydrocephalus shunts.

    PubMed

    Rajasekaran, Sathish; Kovar, Spencer; Qu, Peng; Inwald, David; Williams, Evan; Qu, Hongwei; Zakalik, Karol

    2014-01-01

    The measurement of the flow rate of cerebrospinal fluid (CSF) or existence of CSF flow inside the shunt tube after shunt implant have been reported as tedious process for both patients and doctors; this paper outlines a potential in vitro flow rate measurement method for CSF in the hydrocephalus shunt. The use of implantable titanium elements in the shunt has been proposed to allow for an accurate temperature measurement along the shunt for prediction of CSF flow rate. The CSF flow velocity can be deduced by decoupling the thermal transfer in the measured differential time at a pair of measurement spots of the titanium elements. Finite element analyses on the fluidic and thermal behaviors of the shunt system have been conducted. Preliminary bench-top measurements on a simulated system have been carried out. The measured flow rates, ranging from 0.5 mm/sec to 1.0 mm/sec, which is clinically practical, demonstrate good agreements with the simulation results. PMID:25570411

  9. Effect of rapamycin on hepatic osteodystrophy in rats with portasystemic shunting

    PubMed Central

    van der Merwe, Schalk W; Conradie, Maria M; Bond, Robert; Olivier, Brenda J; Fritz, Elongo; Nieuwoudt, Martin; Delport, Rhena; Slavik, Tomas; Engelbrecht, Gert; Kahn, Del; Shephard, Enid G; Kotze, Maritha J; de Villiers, Nico P; Hough, Stephen

    2006-01-01

    AIM: To study if T-cell activation related to portasystemic shunting causes osteoclast-mediated bone loss through RANKL-dependent pathways. We also investigated if T-cell inhibition using rapamycin would protect against bone loss in rats. METHODS: Portasystemic shunting was performed in male Sprague-Dawley rats and rapamycin 0.1 mg/kg was administered for 15 wk by gavage. Rats received powderized chow and supplemental feeds to prevent the effects of malnutrition on bone composition. Weight gain and growth was restored after surgery in shunted animals. At termination, biochemical parameters of bone turnover and quantitative bone histology were assessed. Markers of T-cell activation, inflammatory cytokine production, and RANKL-dependent pathways were measured. In addition, the roles of IGF-1 and hypogonadism were investigated. RESULTS: Portasystemic shunting caused low turnover osteoporosis that was RANKL independent. Bone resorbing cytokine levels, including IL-1, IL-6 and TNFα, were not increased in serum and TNFα and RANKL expression were not upregulated in PBMC. Portasystemic shunting increased the circulating CD8+ T-cell population. Rapamycin decreased the circulating CD8+ T-cell population, increased CD8+ CD25+ T-regulatory cell population and improved all parameters of bone turnover. CONCLUSION: Osteoporosis caused by portasystemic shunting may be partially ameliorated by rapamycin in the rat model of hepatic osteodystrophy. PMID:16874862

  10. Hydrocephalus and Ventriculoperitoneal Shunts: Modes of Failure and Opportunities for Improvement.

    PubMed

    Jorgensen, Julianne; Williams, Corin; Sarang-Sieminski, Alisha

    2016-01-01

    Between 0.5 and 4 of every 1000 children are born with hydrocephalus. Hydrocephalus is an over-accumulation of cerebrospinal fluid (CSF) in the ventricles of the brain, which can affect cognitive function, vision, appetite, and cranial nerve function. Left untreated, hydrocephalus can result in death. The current treatment for hydrocephalus uses ventriculoperitoneal (VP) shunts with valves to redirect CSF from the ventricles into the peritoneum. Shunt technology is limited by a number of complications, which include infection after implantation, shunt obstruction due to clot formation or catheter obstruction by scar tissue or choroid plexus, disconnection and tubing migration, and overdrainage or underdrainage of CSF due to valve malfunction. While modifications to surgical procedures and shunt design have been introduced, only modest improvements in outcomes have been observed. Here we provide an overview of hydrocephalus, VP shunts, and their modes of failure, and we identify numerous areas of opportunity for biomedical engineers and physicians to collaborate to improve the performance of VP shunts. PMID:27652453

  11. Leigh syndrome: neuropathology and pathogenesis.

    PubMed

    Lake, Nicole J; Bird, Matthew J; Isohanni, Pirjo; Paetau, Anders

    2015-06-01

    Leigh syndrome (LS) is the most common pediatric presentation of a defined mitochondrial disease. This progressive encephalopathy is characterized pathologically by the development of bilateral symmetrical lesions in the brainstem and basal ganglia that show gliosis, vacuolation, capillary proliferation, relative neuronal preservation, and by hyperlacticacidemia in the blood and/or cerebrospinal fluid. Understanding the molecular mechanisms underlying this unique pathology has been challenging, particularly in view of the heterogeneous and not yet fully determined genetic basis of LS. Moreover, animal models that mimic features of LS have only been created relatively recently. Here, we review the pathology of LS and consider what might be the molecular mechanisms underlying its pathogenesis. Data from a wide range of sources, including patient samples, animal models, and studies of hypoxic-ischemic encephalopathy (a condition that shares features with LS), were used to provide insight into the pathogenic mechanisms that may drive lesion development. Based on current data, we suggest that severe ATP depletion, gliosis, hyperlacticacidemia, reactive oxygen species, and potentially excitotoxicity cumulatively contribute to the neuropathogenesis of LS. An intimate understanding of the molecular mechanisms causing LS is required to accelerate the development of LS treatments.

  12. Pathogenesis of benign adrenocortical tumors.

    PubMed

    Vezzosi, Delphine; Bertherat, Jérôme; Groussin, Lionel

    2010-12-01

    Most adrenocortical tumors (ACT) are benign unilateral adrenocortical adenomas, often discovered incidentally. Exceptionally, ACT are bilateral. However bilateral ACT have been very helpful to progress in the pathophysiology of ACT. Although most ACT are of sporadic origin, they may also be part of syndromic and/or hereditary disorders. The identification of the genetics of familial diseases associated with benign ACT has been helpful to define somatic alterations in sporadic ACT: for example, identification of PRKAR1A mutations in Carney complex or alterations of the Wnt/β-catenin pathway in Familial Adenomatous Polyposis Coli. Components of the cAMP signaling pathway-for example, adrenocorticotropic-hormone receptors and other membrane receptors, Gs protein, phosphodiesterases and protein kinase A-can be altered to various degrees in benign cortisol-secreting ACT. These progress have been important for the understanding of the pathogenesis of benign ACT, but already have profound implications for clinical management, for example in unraveling the genetic origin of disease in some patients with ACT. They also have therapeutic consequences, and should help to develop new therapeutic options. PMID:21115158

  13. Pathogenesis of Helicobacter pylori infection.

    PubMed

    Backert, Steffen; Neddermann, Matthias; Maubach, Gunter; Naumann, Michael

    2016-09-01

    Helicobacter pylori is estimated to infect more than half of the worlds human population and represents a major risk factor for chronic gastritis, peptic ulcer disease, MALT lymphoma, and gastric adenocarcinoma. H. pylori infection and clinical consequences are controlled by highly complex interactions between the host, colonizing bacteria, and environmental parameters. Important bacterial determinants linked with gastric disease development include the cag pathogenicity island encoding a type IV secretion system (T4SS), the translocated effector protein CagA, vacuolating cytotoxin VacA, adhesin BabA, urease, serine protease HtrA, secreted outer membrane vesicles, and many others. The high quantity of these factors and allelic changes in the corresponding genes reveals a sophisticated picture and problems in evaluating the impact of each distinct component. Extensive work has been performed to pinpoint molecular processes related to H. pylori-triggered pathogenesis using Mongolian gerbils, mice, primary tissues, as well as novel in vitro model systems such as gastroids. The manipulation of host signaling cascades by the bacterium appears to be crucial for inducing pathogenic downstream activities and gastric disease progression. Here, we review the most recent advances in this important research area. PMID:27531534

  14. Pathogenicity islands in bacterial pathogenesis.

    PubMed

    Schmidt, Herbert; Hensel, Michael

    2004-01-01

    In this review, we focus on a group of mobile genetic elements designated pathogenicity islands (PAI). These elements play a pivotal role in the virulence of bacterial pathogens of humans and are also essential for virulence in pathogens of animals and plants. Characteristic molecular features of PAI of important human pathogens and their role in pathogenesis are described. The availability of a large number of genome sequences of pathogenic bacteria and their benign relatives currently offers a unique opportunity for the identification of novel pathogen-specific genomic islands. However, this knowledge has to be complemented by improved model systems for the analysis of virulence functions of bacterial pathogens. PAI apparently have been acquired during the speciation of pathogens from their nonpathogenic or environmental ancestors. The acquisition of PAI not only is an ancient evolutionary event that led to the appearance of bacterial pathogens on a timescale of millions of years but also may represent a mechanism that contributes to the appearance of new pathogens within a human life span. The acquisition of knowledge about PAI, their structure, their mobility, and the pathogenicity factors they encode not only is helpful in gaining a better understanding of bacterial evolution and interactions of pathogens with eukaryotic host cells but also may have important practical implications such as providing delivery systems for vaccination, tools for cell biology, and tools for the development of new strategies for therapy of bacterial infections.

  15. Pathogenesis of Helicobacter pylori infection.

    PubMed

    Kusters, Johannes G; van Vliet, Arnoud H M; Kuipers, Ernst J

    2006-07-01

    Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori.

  16. Molecular pathogenesis of multiple myeloma.

    PubMed

    Furukawa, Yusuke; Kikuchi, Jiro

    2015-06-01

    Multiple myeloma (MM), one of the most intractable malignancies, is characterized by the infiltration and growth of plasma cells, the most differentiated cells in the B-cell lineage, in the bone marrow. Despite the introduction of novel therapeutic agents, including proteasome inhibitors and immunomodulatory drugs, the prognosis of patients with MM is still worse than that of most hematological malignancies. A better understanding of the molecular pathogenesis of the disease is essential to achieve any improvement of treatment outcome of MM patients. All MM cases pass through the phase of asymptomatic expansion of clonal plasma cells, referred to as monoclonal gammopathy of undetermined significance (MGUS). It has long been believed that MM evolves linearly from MGUS to terminal phases, such as extramedullary tumors and plasma cell leukemia via the accumulation of novel mutations. However, recent studies using next-generation sequencing have disclosed the complex genomic architecture of the disease. At each step of progression, the acquisition of novel mutations is accompanied by subclonal evolution from reservoir clones with branching patterns. Each subclone may carry novel mutations and distinct phenotypes, including drug sensitivity. In addition, minor clones already exist at the MGUS stage, which could expand later in the clinical course, resulting in relapse and/or leukemic conversion. The ultimate goal of treatment is to eradicate all clones, including subclonal populations with distinct biological characteristics. This goal could be achieved by further improving treatment strategies that reflect the genomic landscape of the disease.

  17. The pathogenesis of human cytomegalovirus.

    PubMed

    Griffiths, Paul; Baraniak, Ilona; Reeves, Matt

    2015-01-01

    Human cytomegalovirus (HCMV) is a recognized cause of disease in the fetus, the allograft recipient and AIDS patients. More recently, it has been recognized as a pathogen for those admitted to intensive care units, for the elderly and for the general population. The epidemiology and molecular and cellular pathology of this virus are summarized to provide an overarching model of pathogenesis, able to account for these varying clinical presentations. In brief, HCMV has the potential to spread in the bloodstream to all organs, but only produces overt disease if the viral load increases to high levels. This is normally prevented by a robust immune response, so that the infected individual usually remains asymptomatic. However, this benefit comes at the cost of committing more and more immunological resources to controlling HCMV with time, so that the overall function of the immune system is impaired. Fortunately, recent progress in developing novel antiviral drugs and vaccines suggests the possibility that the diverse effects of HCMV may soon become controllable at the individual and population level, respectively.

  18. Pathogenicity Islands in Bacterial Pathogenesis

    PubMed Central

    Schmidt, Herbert; Hensel, Michael

    2004-01-01

    In this review, we focus on a group of mobile genetic elements designated pathogenicity islands (PAI). These elements play a pivotal role in the virulence of bacterial pathogens of humans and are also essential for virulence in pathogens of animals and plants. Characteristic molecular features of PAI of important human pathogens and their role in pathogenesis are described. The availability of a large number of genome sequences of pathogenic bacteria and their benign relatives currently offers a unique opportunity for the identification of novel pathogen-specific genomic islands. However, this knowledge has to be complemented by improved model systems for the analysis of virulence functions of bacterial pathogens. PAI apparently have been acquired during the speciation of pathogens from their nonpathogenic or environmental ancestors. The acquisition of PAI not only is an ancient evolutionary event that led to the appearance of bacterial pathogens on a timescale of millions of years but also may represent a mechanism that contributes to the appearance of new pathogens within a human life span. The acquisition of knowledge about PAI, their structure, their mobility, and the pathogenicity factors they encode not only is helpful in gaining a better understanding of bacterial evolution and interactions of pathogens with eukaryotic host cells but also may have important practical implications such as providing delivery systems for vaccination, tools for cell biology, and tools for the development of new strategies for therapy of bacterial infections. PMID:14726454

  19. The pathogenesis of measles revisited.

    PubMed

    de Swart, Rik L

    2008-10-01

    Measles continues to be an important cause of childhood mortality in developing countries. The causative agent, measles virus (MV), is a member of the family Paramyxoviridae, genus Morbillivirus, and is spread via the respiratory route. MV was originally thought to enter the host by infecting epithelial cells of the respiratory tract, followed by viremia mediated by infected monocytes. However, neither of these cell types express signaling lymphocyte activation molecule (SLAM, CD150), which has been identified as the main receptor for wild-type MV. Measles has a relatively long incubation time, which makes it difficult to study the early stages of MV infection in humans. The animal models that best reflect the pathogenesis of measles are based on nonhuman primates. The use of recombinant MV strains expressing fluorescent proteins has greatly facilitated studies on viral tropism in macaques. These studies indicate that dendritic cells and lymphocytes expressing CD150 are the primary target cells for MV infection. At late stages of the infection MV also infects epithelial cells, despite the fact that these do not express CD150. Whether these cells express an as yet unidentified additional MV receptor remains unclear. On basis of these data it could be envisaged that dendritic cells are the first target cells for MV infection. These antigen-presenting cells may traffic the virus to the regional lymph nodes where they can transmit the virus to lymphocytes, which during viremia disseminate the virus throughout the body.

  20. Pathogenesis of gut virus infection.

    PubMed

    Salim, A F; Phillips, A D; Farthing, M J

    1990-09-01

    In summary, the pathogenesis of many gut virus infections remains uncertain. However, human and animal studies indicate that the majority of gut viruses infect villous enterocytes. Viruses appear to have different affinities for enterocytes at different sites on the villus. Infection of enterocytes leads to cell death, extrusion into the lumen, and villous atrophy when the rate of cell production in the crypts cannot keep pace with the rate of enterocyte loss. This results in a reduced surface area as well as impairment of digestive and absorptive functions. This may also result in a net secretory state. All these changes, along with others such as reduced enzymatic activity and reduced epithelial integrity, may contribute to the induction of an acute but transient malabsorptive diarrhoea which may persist until the digestive/absorptive functions of the enterocyte are restored. However, if colonic compensation is sufficient to handle the increased fluid load, diarrhoea may not be evident. The roles of villous ischaemia, altered countercurrent exchanger of altered immune responses still remain uncertain and require further investigation. PMID:1962725