Home About us Contact
|
Home About us Contact | ||
|
|
||
IVC
Selected AbstractsNew Annular Tissue Doppler Markers of Pulmonary HypertensionECHOCARDIOGRAPHY, Issue 8 2010Angel López-Candales M.D., F.A.C.C., F.A.S.E. Background: Tissue Doppler imaging (TDI) of mitral (MA) and tricuspid annulus (TA) events characterizes systolic and diastolic properties of each respective ventricle. However, the effect of chronic pulmonary hypertension (cPH) on these TDI annular events has not been well described. Methods: Measurements of right ventricular (RV) performance with TDI of the lateral mitral and tricuspid annuli, to measure isovolumic contraction (IVC) and systolic (S) signals were recorded from 50 individuals without PH and from 50 patients with cPH. To avoid confounding variables, all patients had normal left ventricular ejection fraction and were in normal sinus rhythm at the time of the examination. Results: As expected, markers of RV systolic performance were markedly reduced while LV systolic function remained largely unaffected in cPH patients when compared to patients without PH. TDI interrogation of the MA revealed lengthening of the time interval between IVC and systolic signal (70 ± 17 msec) when compared to individuals without PH (43 ± 8 msec; P < 0.0001). In contrast, cPH markedly shortened the time interval between IVC and the TA systolic signal (34 ± 12 msec) when compared to individuals without PH (65 ± 17 msec; P < 0.0001). Conclusions: cPH lengthens time interval between the IVC and the MA systolic signal while shortening this same interval when the TA is interrogated with TDI; reflecting the potential influence that cPH exerts in biventricular performance. Whether measuring these intervals be routinely used in the follow-up of cPH patients will require further study. (Echocardiography 2010;27:969-976) [source] Incidental Detection of Inferior Vena Caval Dissection by Intraoperative High Frequency Vascular Duplex UltrasonographyECHOCARDIOGRAPHY, Issue 3 2007Sarinya Puwanant M.D. Inferior vena caval (IVC) dissection has been rarely reported. This could be due to less susceptibility of the venous structure to dissect or under recognition of this entity. We first report a case of IVC dissection detected by high frequency surface ultrasonography following tumor thrombectomy of adrenal cortical carcinoma. This report described the value of intraoperative surface echocardiography and reviewed previous literatures with regard to IVC dissection. [source] The Effect of Venture Capital Financing on the Sensitivity to Cash Flow of Firm's InvestmentsEUROPEAN FINANCIAL MANAGEMENT, Issue 4 2010Fabio Bertoni G32; D92; G23 Abstract This work studies the effect of venture capital (VC) financing on firms' investments in a longitudinal sample of 379 Italian unlisted new-technology-based firms (NTBFs) observed over the 10-year period from 1994 to 2003. We distinguish the effects of VC financing according to the type of investor: independent VC (IVC) funds and corporate VC (CVC) investors. Previous studies argue that NTBFs are the firms most likely to be financially constrained. The technology-intensive nature of their activity and their lack of a track record increase adverse selection and moral hazard problems. Moreover, most of their assets are firm-specific or intangible and hence cannot be pledged as collateral. In accordance with this view, we show that the investment rate of NTBFs is strongly positively correlated with their current cash flows. We also find that after receiving VC financing, NTBFs increase their investment rate independently of the type of VC investor. However, the investments of CVC-backed firms remain sensitive to shocks in cash flows, whereas IVC-backed firms exhibit a low and statistically not significant investment,cash flow sensitivity that we interpret as a signal of the removal of financial constraints. [source] The need for venovenous bypass in liver transplantationHPB, Issue 3 2008Hamidreza Fonouni Abstract Since introduction of the conventional liver transplantation (CLTx) by Starzl, which was based on the resection of recipient inferior vena cava (IVC) along the liver, the procedure has undergone several refinements. Successful use of venovenous bypass (VVB) was first introduced by Shaw et al., although in recent decades there has been controversy regarding the routine use of VVB during CLTx. With development of piggyback liver transplantation (PLTx), the use of caval clamping and VVB is avoided, leading to fewer complications related to VVB. However, some authors still advocate VVB in PLTx. The great diversity among centers in their use of VVB during CLTx, or even along the PLTx technique, has led to confusion regarding the indication setting for VVB. For this reason, we present an overview of the use of VVB in CLTx, the target of patients for whom VVB could be beneficial, and the needs assessment of VVB for patients undergoing PLTx. Recent studies have shown that with the advancement of surgical skills, refinement of surgical techniques, and improvements in anesthesiology, there are only limited indications for doing CLTx with VVB routinely. PLTx with preservation of IVC can be performed in almost all primary transplants and in the majority of re-transplantations without the need for VVB. Nevertheless, in a few selective cases with severe intra-operative hemodynamic instability, or with a failed test of transient IVC occlusion, the application of VVB is still justifiable. These indications should be judged intra-operatively and the decision is based on each center's preference. [source] Clinical outcome of surgical management for patients with renal cell carcinoma involving the inferior vena cavaINTERNATIONAL JOURNAL OF UROLOGY, Issue 9 2007Tomoaki Terakawa Background: The objective of this study was to evaluate the clinical outcome after surgical management of renal cell carcinoma (RCC) extending to the inferior vena cava (IVC). Methods: This study included a total of 55 patients (41 men and 14 women; mean age, 59.3 years) with RCC (39 right- and 16 left-sided tumors) involving the IVC, who underwent radical nephrectomy and tumor thrombectomy between 1983 and 2005 at a single institution in Japan. The level of thrombus was classified as follows: level I, infrahepatic; level II, intrahepatic; level III, suprahepatic; and level IV, extending to the atrium. Clinicopathological data from these patients were retrospectively reviewed to identify factors associated with survival. Results: There were 11 and 18 patients who were diagnosed as having lymph node and distant metastases, respectively. Twenty-two patients had tumor thrombus in level I, 20 in level II, 10 in level III, and 3 in level IV. Pathological examinations demonstrated that 34 and 21 patients had clear cell carcinoma and non-clear cell carcinoma, respectively, 42, 9 and 4 were pT3b, pT3c and pT4, respectively, and 6, 35 and 14 were Grades 1, 2 and 3, respectively. Cancer-specific 1-, 3- and 5-year survival rates of these 55 patients were 74.5%, 51.4% and 30.3%, respectively. Among several factors examined, clinical stage (P = 0.047), lymph node metastasis (P = 0.016), histological subtype (P = 0.034) and tumor grade (P < 0.001) were significantly associated with cancer-specific survival by univariate analysis. Furthermore, multivariate analysis demonstrated clinical stage (P = 0.037) and tumor grade (P < 0.001) as independent predictors of cancer-specific survival irrespective of other significant factors identified by univariate analysis. Conclusions: In patients with RCC involving the IVC, biological aggressiveness characterized by tumor grade rather than tumor extension would have more potential prognostic importance; therefore, more intensive multimodal therapy should be considered in patients with high grade RCC with tumor thrombus extending into the IVC. [source] Intraoperative transesophageal echocardiography for inferior vena caval tumor thrombus in renal cell carcinomaINTERNATIONAL JOURNAL OF UROLOGY, Issue 4 2004TAKEHIRO OIKAWA Abstract Background : We investigated the advantages of intraoperative transesophageal echocardiography (TEE) during inferior vena caval tumor thrombectomy in renal cell carcinoma (RCC). Methods : Five patients with RCC that extended into the inferior vena cava (IVC) underwent radical nephrectomy. To remove the tumor thrombus in the IVC, an inflated Fogarty balloon catheter was used to pull the thrombus below the level of the hepatic veins with real-time TEE monitoring. Results : In all cases, TEE monitoring during surgery provided an accurate and excellent view of the IVC thrombus. TEE was particularly helpful for the thrombectomy to minimize hepatic mobilization by using occlusion balloon catheter in two patients whose thrombus extended to the intrahepatic IVC. Conclusions : Intraoperative real-time TEE monitoring is a safe, minimally invasive technique that can provide accurate information regarding the presence and extent of IVC involvement, guidance for placement of a vena caval clamp, confirmation of complete removal of the IVC thrombus and intervention using catheters to assist in thrombectomy. [source] Solitary floating vena caval thrombus as a late recurrence of renal cell carcinomaINTERNATIONAL JOURNAL OF UROLOGY, Issue 4 2004ANDREA MINERVINI Abstract We report an unusual case of solitary thrombus floating in the inferior vena cava (IVC) in a patient who underwent radical nephrectomy for a renal cell carcinoma (RCC) of the right kidney extended into the renal vein with no capsular and perinephric tissue invasion (pT3b). Twenty months after surgery, a routine computed tomography scan identified an intraluminal mass floating in the IVC. Cavotomy and thrombectomy with no caval resection were successfully performed. A review of the literature showed only three previous published cases of RCC recurring in the IVC only, with no local recurrence or distant metastases. We outline the possible etiology of these unusual and solitary recurrences in the IVC and we emphasize the need for a strict surveillance for all patients with RCC and especially for those with pT1b, pT2 and pT3 disease. An early diagnosis of this rare recurrence can permit an easy removal of the thrombus with no caval resection and graft replacement, making this disease potentially curable by surgery. [source] Deep Hypothermia and Circulatory Arrest in the Surgical Management of Renal Tumors with Cavoatrial ExtensionJOURNAL OF CARDIAC SURGERY, Issue 6 2009Panagiotis Dedeilias M.D. Their intraluminar extension to the cardiac cavities occurs with a tumor-thrombus formation at a percentage of 1%. The aim of this study is to present the principles of "radical" management that should be targeted to excision of the kidney together with the cavoatrial tumor-thrombus. Material: From 2003 through 2008, we treated six patients with renal-cell carcinoma involving the IVC and/or the right cardiac chambers. The main symptoms leading to the diagnosis were hematuria, dyspnea, or lower limb edema. The extension of the tumor was type IV in three cases, type III in two, and type II in one case. Method: Extracorporeal circulation combined with a short period of hypothermic circulatory arrest was the method used. Radical nephrectomy combined with cavotomy and atriotomy was performed to an "en-block" extirpation of the tumor-thrombus and allowed oncologic surgical clearance of the disease. Results: There was no operative death. The mean postoperative course duration was 11 days, apart from one obese patient who presented postoperative pancreatitis and died on the 44th postoperative day due to respiratory failure. During the cumulative postoperative follow-up of 171 months the patients remain free of recurrence. Conclusions: The use of extracorporeal circulation and deep hypothermic circulatory arrest provides a good method for radical excision of renal carcinomas involving the IVC with satisfactory morbidity and long-term survival results. Cooperation of urologists and cardiac surgeons is necessary for this type of operation. [source] Frequency Analysis of Atrial Electrograms Identifies Conduction Pathways from the Left to the Right Atrium During Atrial Fibrillation,Studies in Two Canine ModelsJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 6 2009KYUNGMOO RYU Ph.D. Studies of atrial fibrillation (AF) have demonstrated that a stable rhythm of very short cycle length in the left atrium (LA) can cause fibrillatory conduction in the rest of the atria. We tested the hypothesis that fast Fourier transform (FFT) analysis of atrial electrograms (AEGs) during this AF will rapidly and reliably identify LA-to-right atrium (RA) conduction pathway(s) generated by the driver. Methods and Results: During induced atrial tachyarrhythmias in the canine sterile pericarditis and rapid ventricular pacing-induced congestive heart failure models, 380,404 AEGs were recorded simultaneously from epicardial electrodes on both atria. FFT analysis of AEGs during AF demonstrated a dominant frequency peak in the LA (driver), and multiple frequency peaks in parts of the LA and the most of the RA. Conduction pathways from the LA driver to the RA varied from study-to-study. They were identified by the presence of multiple frequency peaks with one of the frequency peaks at the same frequency as the driver, and traveled (1) inferior to the inferior vena cava (IVC); (2) between the superior vena cava and the right superior pulmonary vein (RSPV); (3) between the RSPV and the right inferior pulmonary vein (RIPV); (4) between the RIPV and the IVC; and (5) via Bachmann's bundle. Conduction pathways identified by FFT analysis corresponded to the conduction pathways found in classical sequence of activation mapping. Computation time for FFT analysis for each AF episode took less than 5 minutes. Conclusion: FFT analysis allowed rapid and reliable detection of the LA-to-RA conduction pathways in AF generated by a stable and rapid LA driver. [source] Endocardial Implantation of a Cardioverter Defibrillator in Early ChildhoodJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 12 2005MAURIZIO GASPARINI M.D. Introduction: Experience in endovascular/endocardial techniques for implanting implantable cardioverter defibrillators in early childhood is limited. Potentially, this type of approach could limit the surgical risk, while increasing ICD therapy efficacy. The safety and feasibility of adopting a complete endovascular/endocardial approach for implanting ICDs is assessed by considering the cases of two young children. Methods and Results: Two boys, aged 3 and 6 years, were implanted with ICD for a history of syncope and documented ventricular tachycardia (VT). A complete endovascular/endocardial approach was adopted consisting of positioning a bipolar pacing and sensing lead in the right ventricular (RV) apex with intravascular redundancy forming a loop in the inferior vena cava (IVC), and a caval coil placed in the IVC. Sensing values (7,8 mV), pacing threshold (0.5,0.6 V/0.5 msec), and defibrillation testing (case 1 = 10 J, case 2 = 20 J) were all acceptable. During follow-up, in both cases ICD intervened correctly. In one case, 16 months after implantation, because of change in the IVC coil-active can vector, the IVC coil was effectively repositioned to a more distal position. Conclusion: A complete endovascular/endocardial ICD implantation technique in early childhood is both feasible and safe. This approach avoids thoracotomy and ensures ICD therapy efficacy. [source] Transvenous Parasympathetic Nerve Stimulation in the Inferior Vena Cava and Atrioventricular ConductionJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 1 2000PATRICK SCHAUERTE M.D. Parasympathetic Stimulation in the Inferior Vena Cava. Introduction: In previous reports, we demonstrated a technique for parasympathetic nerve stimulation (PNS) within the superior vena cava, pulmonary artery, and coronary sinus to control rapid ventricular rates during atrial fibrillation (AF). In this report, we describe another vascular site, the inferior vena cava (IVC), at which negative dromotropic effects during AF could consistently he obtained. Moreover, stimulation at this site also induced dual AV nodal electrophysiology. Methods and Results: PNS was performed in ten dogs using rectangular stimuli (0.1 msec/20 Hz) delivered through a catheter with an expandable electrode basket at its tip. Within 3 minutes and without using fluoroscopy, the catheter was positioned at an effective PNS site in the IVC at the junction of the right atrium. AF was induced and maintained by rapid atrial pacing. During stepwise increase of the PNS voltage from 2 to 34 V, a graded response of ventricular rate slowing during AF was observed (266 ± 79 msec without PNS vs 1,539 ± 2,460 msec with PNS at 34 V; P = 0.005 by analysis of variance), which was abolished by atropine and blunted by hexamethonium. In three animals, PNS was performed during sinus rhythm. Dual AV nodal electrophysiology was present in 1 of 3 dogs in control, whereas with PNS, dual AV nodal electrophysiology was observed in all three dogs. PNS did not significantly change sinus rate or arterial blood pressure during ventricular pacing. Conclusion: Stable and consistent transvenous electrical stimulation of parasympathetic nerves innervating the AV node can be achieved in the IVC, a transvenous site that is rapidly and readily accessible. The proposed catheter approach for PNS can be used to control ventricular rate during AF in this animal model. [source] Unusual hepatic-portal-systemic shunting demonstrated by Doppler sonography in children with congenital hepatic vein ostial occlusionJOURNAL OF CLINICAL ULTRASOUND, Issue 4 2004Maha Barakat MD Abstract Purpose This report describes unusual changes in the hepatic vasculature in 3 children presenting with upper gastrointestinal hemorrhage. Methods The study included 3 children (ages 5,8 years) who presented with hematemesis. All had mild hepatosplenomegaly and normal liver function. Esophageal varices were demonstrated in all on upper endoscopy. Color and spectral Doppler sonography was performed to assess the hepatic vasculature, including the hepatic veins (HVs), portal vein (PV), hepatic artery (HA), and inferior vena cava (IVC). Results The HVs were all patent but with ostial occlusion at the point of their communication with the IVC. Complete flow reversal was shown inside the HVs, with blood draining into collateral vessels at the liver surface and paraumbilical vein. In one patient, the paraumbilical vein could be traced to its communication with the right external iliac vein. In all children, the direction of flow in the PV, HA, and IVC was normal. After endoscopic sclerotherapy, all children were shown to be in good general condition and to have normal liver function for a follow-up period of 15,36 months. Conclusions Ostial occlusion of the HV is a rare cause of hepatic outflow obstruction in children. Doppler sonography is a valuable, noninvasive imaging technique for evaluation of the hepatic vasculature and the accompaning shunting pathways in such cases. © 2004 Wiley Periodicals, Inc. J Clin Ultrasound 32:172,178, 2004; Published online in Wiley InterScience (www. interscience.wiley.com). DOI: 10.1002/jcu.20019 [source] Aneurysms of the inferior vena cavaJOURNAL OF MEDICAL IMAGING AND RADIATION ONCOLOGY, Issue 1 2003Rahul Sheth Summary Two cases of saccular aneurysms of the infrarenal inferior vena cava (IVC) associated with retrohepatic IVC obstruction are described. Ultrasonographic, computerized tomographic and inferior venacavography findings in these cases are presented. [source] Combined liver and inferior vena cava resection for hepatic malignancyJOURNAL OF SURGICAL ONCOLOGY, Issue 3 2007Spiros G. Delis MD Abstract Objective The experience from a single center, in combined liver and inferior vena cava (IVC) resection for liver tumors, is presented. Methods Twelve patients underwent a combined liver resection with IVC replacement. The median age was 45 years (range 35,67 years). Resections were carried out for hepatocellular carcinoma (n,=,4), colorectal metastases (n,=,6), and cholangiocarcinoma (n,=,2). Liver resections included eight right lobectomies and four left trisegmentectomies. The IVC was reconstructed with ringed Gore-Tex tube graft. Results No perioperative deaths were reported. The median operative blood transfusion requirement was 2 units (range 0,12 units) and the median operative time was 5 hr. Median hospital stay was 10 days (range 8,25 days). Three patients had evidence of postoperative liver failure, resolved with supportive management. Two patients developed bile leaks, resolved conservatively. With a median follow up of 24 months, all vascular reconstructions were patent and no evidence of graft infection was documented. Conclusions Aggressive surgical management of liver tumors, offer the only hope for cure or palliation. We suggest that liver resection with vena cava replacement may be performed safely, with acceptable morbidity, by specialized surgical teams. J. Surg. Oncol. 2007;96: 258,264. © 2007 Wiley-Liss, Inc. [source] Resection and reconstruction of retrohepatic vena cava without venous graft during major hepatectomiesJOURNAL OF SURGICAL ONCOLOGY, Issue 1 2007Marcel Autran C. Machado MD Abstract Background Progress in liver surgery has enabled hepatectomy with concomitant venous resection for liver malignancies involving the inferior vena cava (IVC). The authors describe an alternative technique for IVC reconstruction without the need of graft. Methods Parenchymal transection is performed from anterior surface of the liver down to the anterior or left lateral surface of the IVC using combination of two techniques reported elsewhere. IVC is clamped above and below the tumor and the liver in continuity with an invaded segment of IVC is removed en bloc. A transverse anastomosis of IVC is performed starting with running suture on the posterior wall followed by the anterior wall. Results This approach has been successfully employed in eight consecutive patients with IVC involvement. The procedures performed were 5 right hepatectomies, 1 right posterior sectionectomy, 1 right trisectionectomy, and 1 left trisectionectomy. Two patients needed total vascular exclusion (TVE) for 11 and 10 min, respectively. Blood transfusion was necessary in three patients. Pathologic surgical margins were free in all cases. No postoperative mortality was observed. Conclusion This technique of IVC reconstruction precludes the use of graft and minimizes the use of TVE decreasing ischemic damage to the remnant liver. J. Surg. Oncol. 2007;96:73,76. © 2007 Wiley-Liss, Inc. [source] 13C-methacetin breath test as liver function test in patients with chronic hepatitis C virus infectionALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 2 2005B. Braden Summary Background :,The 13C-methacetin breath test enables the quantitative evaluation of the cytochrome P450-dependent liver function. Aim :,To find out whether this breath test is sensitive in noncirrhotic patients also with chronic hepatitis C in early stages of fibrosis. Methods :,Sixty-one healthy controls and 81 patients with chronic hepatitis C underwent a 13C-methacetin breath test. In all patients, a liver biopsy was performed. The liver histology was classified according to the histology activity index,Knodell score. Results :,Delta over baseline values of the patients at 15 min significantly differed from controls (19.2 ± 9.2, vs. 24.1 ± 5.7,; P < 0.003). The cumulative recovery after 30 min in patients was 11.4 ± 4.8% and in healthy controls 13.8 ± 2.8% (P < 0.002). However, patients with early fibrosis (histology activity index IVB) did not differ in delta over baseline values of the patients at 15 min (23.2 ± 7.9, vs. 22.6 ± 7.2,; P = 0.61) or cumulative recovery (13.6 ± 3.7% vs. 13.2 ± 3.8%; P = 0.45) from patients with more advanced fibrosis (histology activity index IVC). Patients with clinically nonsymptomatic cirrhosis (histology activity index IVD; Child A) metabolized 13C-methacetin to a significantly lesser extent (delta over baseline values of the patients at 15 min: 8.3 ± 4.9,; P < 0.005 and cumulative recovery after 30 min: 5.6 ± 3.2%; P < 0.003). The 13C-methacetin breath test identified cirrhotic patients with 95.0% sensitivity and 96.7% specificity. Conclusion :,The non-invasive 13C-methacetin breath test reliably distinguishes between early cirrhotic (Child A) and noncirrhotic patients, but fails to detect early stages of fibrosis in patients with chronic hepatitis C. [source] Paralysis in the left phrenic nerve after living-donor liver transplantation for biliary atresia with situs inversusLIVER TRANSPLANTATION, Issue 11 2008Yukihiro Sanada A 7-month-old boy with biliary atresia accompanied by situs inversus and absent inferior vena cava (IVC) underwent living-donor liver transplantation (LDLT). Because a constriction in the recipient hepatic vein (HV) was detected during the preparation of the HV in LDLT, a dissection in the cranial direction and a total clamp of the suprahepatic IVC was performed, and the suprahepatic IVC and the graft HV were anastomosed end-to-end. Postoperatively, atelectasis in the left upper lobe and ventilator failure accompanied by an elevation of the left hemidiaphragm were observed and mechanical ventilation was repetitively required. Paralysis in the left phrenic nerve was diagnosed by chest radiograph and ultrasonography. In our patient, conservative treatment was administrated, because weaning him from mechanical ventilation was possible a few days after intubation and the ventilator function was expected to be improved with growth. The disease course was good, and he was discharged from the hospital at 78 days after LDLT. Complications of paralysis in the phrenic nerve after cadaveric liver transplantation have been reported to be high. Although using a conventional technique during the reconstruction of the HV may injure the phrenic nerve directly, use of the piggyback technique with preservation of the IVC is rare. Even if LDLT was undertaken, a dissection of the HV or a total clamp of the suprahepatic IVC as a conventional technique can directly injure the phrenic nerve. Therefore, a dissection of the HV or a total clamp of the suprahepatic IVC at the reconstruction of the HV in LDLT should be carefully performed, and the possibility of paralysis in the phrenic nerve should be considered in patients with a relapse of respiratory symptoms and an elevation of the hemidiaphragm after LDLT. Liver Transpl 14:1659,1663, 2008. © 2008 AASLD. [source] Venous outflow obstruction in liver transplantation is associated with the anastomotic techniqueLIVER TRANSPLANTATION, Issue 12 2007James D. Perkins M.D. Special Editor The outflow venovenous anastomosis represent a crucial aspect during orthotopic liver transplantation (OLT) with inferior vena cava (IVC) preservation. The modified Belghiti liver hanging maneuver applied to the last phase of hepatectomy, lifting the liver, provides a better exposure of the suprahepatic region and allows easier orthogonal clamping of the three suprahepatic veins with a minimal portion of IVC occlusion. The outflow anastomosis constructed with a common cloacae of the three native suprahepatic veins is associated with a lower incidence of graft related venous outflow complications. The procedure planned in 120 consecutive OLT was achieved in 118 (99%). The outflow anastomosis was constructed on the common cloaca of the three hepatic veins in 111/120 cases (92.5%). No major complications were observed (bleeding during tunnel creation, graft outflow dysfunction, etc) except in one patient with acute Budd-Chiari, who successfully underwent retransplantation. [source] In vivo study of microbubbles as an MR susceptibility contrast agentMAGNETIC RESONANCE IN MEDICINE, Issue 3 2004Kelvin K. Wong Abstract The potential application of gas microbubbles as a unique intravascular susceptibility contrast agent for MRI has not been fully explored. In this study, the MR susceptibility effect of an ultrasound microbubble contrast agent, Optison®, was studied with rat liver imaging at 7 T. Optison® suspension in two different doses (0.15 mL/kg and 0.4 mL/kg) was injected into rats, and induced transverse relaxation rate increases (,R2*) of 29.1 ± 1.6 s,1 (N = 2) and 61.5 ± 12.9 s,1 (N = 6), respectively, in liver tissue. Liver uptake of intact albumin microbubbles was observed 10 min after injection. Eight of the 16 rats studied showed no susceptibility enhancement. This is probably attributable to the intravascular microbubble growth due to transmural CO2 supersaturation in the cecum and colon in small animals that causes microbubble aggregation and trapping in the inferior vena cava (IVC). In vitro ,R2* measurements of Optison® suspension at different concentrations are also reported. Magn Reson Med 52:445,452, 2004. © 2004 Wiley-Liss, Inc. [source] Inferior Vena Cava Percentage Collapse During Respiration Is Affected by the Sampling Location: An Ultrasound Study in Healthy VolunteersACADEMIC EMERGENCY MEDICINE, Issue 1 2010David J. Wallace MD Abstract Objectives:, Physicians are unable to reliably determine intravascular volume status through the clinical examination. Respiratory variation in the diameter of the inferior vena cava (IVC) has been investigated as a noninvasive marker of intravascular volume status; however, there has been a lack of standardization across investigations. The authors evaluated three locations along the IVC to determine if there is clinical equivalence of the respiratory percent collapse at these sites. The objective of this study was to determine the importance of location when measuring the IVC diameter during quiet respiration. Methods:, Measurements of the IVC were obtained during quiet passive respiration in supine healthy volunteers. All images were recorded in B-mode, with cine-loop adjustments in real time, to ensure that maximum and minimum IVC dimensions were obtained. One-way repeated-measures analysis of variance (ANOVA) was used for comparison of IVC measurement sites. Results:, The mean (±SD) percentage collapse was 20% (±16%) at the level of the diaphragm, 30% (±21%) at the level of the hepatic vein inlet, and 35% (±22%) at the level of the left renal vein. ANOVA revealed a significant overall effect for location of measurement, with F(2,35) = 6.00 and p = 0.006. Contrasts showed that the diaphragm percentage collapse was significantly smaller than the hepatic (F(1,36) = 5.14; p = 0.03) or renal caval index (F(1,36) = 11.85; p = 0.002). Conclusions:, Measurements of respiratory variation in IVC collapse in healthy volunteers are equivalent at the level of the left renal vein and at 2 cm caudal to the hepatic vein inlet. Measurements taken at the junction of the right atrium and IVC are not equivalent to the other sites; clinicians should avoid measuring percentage collapse of the IVC at this location. ACADEMIC EMERGENCY MEDICINE 2010; 17:96,99 © 2009 by the Society for Academic Emergency Medicine [source] Rat liver transplantation for total vascular reconstruction, using a suture methodMICROSURGERY, Issue 5 2003Seiichiro Inoue M.D. We developed a novel protocol for rat orthotopic liver transplantation (OLT), using a suture method to establish hepatic artery flow. After determining that early inferior vena cava (IVC) unclamping maintained better circulation compared with the portal vein (PV) using porto-systemic shunted recipients, we developed a rat OLT model with total vascular reconstruction using a suture method. After connecting the suprahepatic IVC, the infrahepatic IVC was anastomosed, using a running suture method. IVC circulation was established immediately. The PV was anastomosed without intestinal congestion, using porto-systemic shunted recipients. The aortic conduit, including the donor celiac and hepatic artery, was anastomosed to the recipient abdominal aorta end-to-side. Eight of 11 OLT cases (72.7%) survived indefinitely. Biliary connection was achieved using a one-stent method. Three cases died 3,5 days postoperatively. Hepatic angiography showed good patency. The graft liver was histologically normal in long-surviving rats. © 2003 Wiley-Liss, Inc. MICROSURGERY 23:470,475 2003 [source] New model for simultaneous heart and kidney transplantation in miceMICROSURGERY, Issue 2 2003Minghui Wang M.D. In clinical settings, combined heart and kidney transplantation results in a lower incidence of cardiac graft and renal graft rejection as compared to isolated heart and kidney transplantation. To study the phenomenon in an experimental setting, we developed a model of combined heart and kidney transplantation in mice. According to our technique, we kept the patch of the infrarenal aorta and inferior vena cava (IVC) as long as possible during the donor's kidney explantation, and then, after finishing the kidney implantation with conventional techniques, we anastomosed the innominate artery and pulmonary artery of the heart graft to the patch of the infrarenal aorta and IVC of the renal graft, respectively, instead of the recipient's aorta and IVC. With the use of our method, combined heart and kidney transplantation in mice can be performed to get enough suture room for the second graft, to avoid prolonging the occlusion time of the recipient's circulation, and to profoundly decrease postoperative complications such as paraplegia and mortality. Of the 14 recipients with combined heart-kidney isografting, 10 have been successful (71.4%), surviving over 100 days with normal function of both grafts, and with lack of change in histological appearance. This suggests that the technique is feasible and reliable. © 2003 Wiley-Liss, Inc. MICROSURGERY 23:164,168 2003 [source] A new vascularized adrenal transplantation model in the ratMICROSURGERY, Issue 4 2001Dingyi Liu M.D. A new microsurgical model of adrenal transplantation in the rat is described. An adrenal graft with its vascular supply, adrenal artery and vein, and the attachment of a segment of aorta and inferior vena cava (IVC) was transplanted to a recipient rat with end-to-side anastomoses between the donor IVC segment and the recipient IVC and between the donor aortic segment and the recipient aorta using 10-0 nylon sutures. Using this model, different groups of recipient rats received iso- or allograft with or without immunosuppressive treatment were tested. This model provides a reliable and useful tool for research on endocrinology. © 2001 Wiley-Liss, Inc. MICROSURGERY 21:124,126 2001 [source] Noncatheter-Based Delivery of a Single-Chamber Lumenless Pacing Lead in Small ChildrenPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 7 2007DAMIEN KENNY M.B.Ch.B., M.R.C.P.C.H. Objectives:The model 3830 lead (SelectSecureÔ Medtronic, Minneapolis, MN, USA) is a bipolar, fixed-screw, 4.1-F pacing lead designed for site-selective pacing. Implantation is usually performed using an 8-F deflectable catheter system. This catheter is not ideal for smaller children because of both the sheath size and the relatively large deflected curves. We describe a simpler noncatheter-based delivery system in seven children. Methods:A 4.1-F SelectSecure lead was introduced via a 5-F SafeSheath (Thomas Medical, Malvern, PA, USA) placed in the left subclavian vein. The SelectSecure lead was passed into the inferior vena cava (IVC) and a loop created, which was then withdrawn into the right atrium. Once in position, the lead was screwed into the myocardium, the SafeSheath was peeled off, and the lead connected to the generator. Results:From March 2005 until September 2006, five right atrial leads and two right ventricular leads were implanted in seven patients (six female) with a median weight of 15 kg (8.1,19.4). All leads were successfully placed with excellent pacing thresholds. The median screening time was 7.1 minutes (4.8,11.4) with a median radiation dose of 83 cGy cm2. There were no procedural complications and no lead displacements seen on a median follow-up of 10 months. Conclusions:Delivery of the 4.1-F SelectSecure pacing lead to the right heart is possible using a noncatheter-based delivery system. This is effective and safe and does not require the use of a larger delivery system. This allows these thin isodiametric pacing leads to be used advantageously in small children. [source] Successful adult-to-child renal transplantation utilizing the ovarian vein in children with inferior vena cava/iliac vein thrombosisPEDIATRIC TRANSPLANTATION, Issue 6 2010Ran Tao Tao R, Shapiro R. Successful adult-to-child renal transplantation utilizing the ovarian vein in children with inferior vena cava/iliac vein thrombosis. Pediatr Transplantation 2010: 14:E70,E74. © 2009 John Wiley & Sons A/S. Abstract:, IVC/iliac vein thrombosis has previously been considered to be a contraindication to renal transplantation because of the technical difficulties and the increased risk of graft thrombosis. We report two successful cases of adult-to-child kidney transplantation in which we anastomosed the graft renal vein to the recipient ovarian vein in the presence of IVC and/or iliac vein thrombosis, with no short or long term vascular complications. Our experience, which adds to the successful reports from several other centers, suggests that the inability to use the iliocaval axis should no longer be considered a contraindication to pediatric renal transplantation. [source] Specific response of ultra-thin metal oxide films to gasPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2009etkus Abstract Tin and indium oxide ultra-thin film (UTF) based structures are investigated in the present study. Current-voltage characteristics (IVC) are measured in the samples by a contact current mode of scanning probe microscopy (SPM). It is proved that the IVC splits into two paths corresponding to increase and decrease of applied voltage, respectively. Detailed investigations of the electrical properties of the ultra-thin metal oxide (MOX) films revealed a dependence of the IVC on the structure of the films, on initial conductivity and on the surrounding gases. It was proved that the IVC is typically split only if the maximum dc-voltage exceeds some critical magnitude that is not the same in indium and tin oxide based films. The properties of the ultra-thin MOX structures are explained in terms of distribution of stoichiometry in MOX based nanometer systems. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Effects of progressive drought stress on the expression of patatin-like lipid acyl hydrolase genes in Arabidopsis leavesPHYSIOLOGIA PLANTARUM, Issue 1 2008Ana Rita Matos Patatin-like genes have recently been cloned from several plant species and found to be involved in stress responses and development. In previous work, we have shown that a patatin-like gene encoding a galactolipid acyl hydrolase (EC 3.1.1.26) was stimulated by drought in the leaves of the tropical legume, Vigna unguiculata L. Walp. The aim of the present work was to study the expression of patatin-like genes in Arabidopsis thaliana under water deficit. Expression of six genes was studied by reverse transcriptase polymerase chain reaction in leaves of plants submitted to progressive drought stress induced by withholding water and also in different plant organs. Three genes, designated AtPAT IIA, AtPAT IVC and AtPAT IIIA, were shown to be upregulated by water deficit but with different kinetics, while the other patatin-like genes were either constitutive or not expressed in leaves. The accumulation of transcripts of AtPAT IIA in the early stages of the drought treatment was coordinated with the upregulation of lipoxygenase and allene oxide synthase genes. AtPAT IIA expression was also induced by wounding and methyl jasmonate treatments. The in vitro lipolytic activity toward monogalactosyldiacylglycerol, digalactosyldiacylglycerol, phosphatidylcholine and phosphatidylglycerol was confirmed by producing the recombinant protein ATPAT IIA in insect cells. The analysis of free fatty acid pools in drought-stressed leaves shows an increase in the relative amounts of trans-3-hexadecenoic acid at the beginning of the treatment followed by a progressive accumulation of linoleic and linolenic acids. The possible roles of AtPAT IIA in lipid signaling and membrane degradation under water deficit are discussed. [source] Prenatal diagnosis of ductus venosus agenesis and its association with cytogenetic/congenital anomaliesPRENATAL DIAGNOSIS, Issue 11 2002Paolo Volpe Abstract Objectives We present an observational study of 12 cases of anomalies of the umbilical and portal vein systems associated with absence of the ductus venosus (DV) diagnosed over the past 5 years. The hemodynamic implications of each pattern of umbilico-portal system anomalies associated with absence of the DV have been investigated, as well as the frequency and types of associated anomalies and their embryological origin. Methods In all cases ultrasound, color Doppler, and cytogenetic investigations were performed. Results Four main patterns of abnormal venous circulation were documented: (1) the umbilical vein (UV) bypasses the liver and drains into the right atrium directly or through a dilated coronary sinus (three cases); (2) the UV bypasses the liver, with an infrahepatic or suprahepatic connection directly to the inferior vena cava (IVC) (two cases); (3) the UV bypasses the liver and drains directly into the iliac or renal veins (four cases); and (4) the UV drains directly into the portal veins (three cases). Among seven cases with other associated anomalies (58%), there were three cases of Turner's and Noonan's syndromes. Two fetuses and two neonates died and there were two terminations of pregnancy (TOP). Conclusions In utero diagnosis of ultrasound patterns associated with DV anomalies is feasible. Fetal karyotyping should be considered, serial ultrasound examinations recommended and, in the presence of heart failure, delivery can be anticipated. Copyright © 2002 John Wiley & Sons, Ltd. [source] A new generation of protein display scaffolds for molecular recognitionPROTEIN SCIENCE, Issue 1 2006Ralf J. Hosse Abstract Engineered antibodies and their fragments are invaluable tools for a vast range of biotechnological and pharmaceutical applications. However, they are facing increasing competition from a new generation of protein display scaffolds, specifically selected for binding virtually any target. Some of them have already entered clinical trials. Most of these nonimmunoglobulin proteins are involved in natural binding events and have amazingly diverse origins, frameworks, and functions, including even intrinsic enzyme activity. In many respects, they are superior over antibody-derived affinity molecules and offer an ever-extending arsenal of tools for, e.g., affinity purification, protein microarray technology, bioimaging, enzyme inhibition, and potential drug delivery. As excellent supporting frameworks for the presentation of polypeptide libraries, they can be subjected to powerful in vitro or in vivo selection and evolution strategies, enabling the isolation of high-affinity binding reagents. This article reviews the generation of these novel binding reagents, describing validated and advanced alternative scaffolds as well as the most recent nonimmunoglobulin libraries. Characteristics of these protein scaffolds in terms of structural stability, tolerance to multiple substitutions, ease of expression, and subsequent applications as specific targeting molecules are discussed. Furthermore, this review shows the close linkage between these novel protein tools and the constantly developing display, selection, and evolution strategies using phage display, ribosome display, mRNA display, cell surface display, or IVC (in vitro compartmentalization). Here, we predict the important role of these novel binding reagents as a toolkit for biotechnological and biomedical applications. [source] Effect of Alpha-Tocopherol and Ascorbic Acid on Bovine Oocyte in Vitro MaturationREPRODUCTION IN DOMESTIC ANIMALS, Issue 2 2005G Dalvit Contents In vitro culture results in higher oxygen concentrations than in vivo environments, leading to an increased level of reactive oxygen species (ROS) that cause lipid peroxidation of cellular membranes. Alpha-tocopherol (active form of vitamin E) is an antioxidant that protects mammalian cells against lipid peroxidation, which is regenerated by ascorbic acid. The aim of this study was to determine the effect of the addition of alpha-tocopherol and/or ascorbic acid to the maturation medium on bovine oocyte in vitro maturation (IVM) and subsequently on in vitro fertilization (IVF) and embryo development. Cumulus,oocyte complexes (COCs) were matured in Medium 199 (control), and with the addition of alpha-tocopherol and/or ascorbic acid. The concentration of alpha-tocopherol in COCs was determined by high-performance liquid chromatography (HPLC). IVF and in vitro culture (IVC) were carried out in modified synthetic oviductal fluid (mSOF). The quantity of alpha-tocopherol naturally present in COCs diminished by half during IVM (p < 0.05), although in the presence of ascorbic acid it remained constant. A greater amount of alpha-tocopherol was detected in COCs matured in medium supplemented with this antioxidant (p < 0.05), but the addition of alpha-tocopherol plus ascorbic acid maintained higher levels of alpha-tocopherol (p < 0.05). Significant differences were not observed in the percentages of nuclear maturation and fertilization among different treatments. The presence of alpha-tocopherol or ascorbic acid in the maturation medium failed to modify the percentage of blastocysts obtained, unlike the addition of both antioxidants when a significant decrease was observed (p < 0.05). Absorbic acid maintained the antioxidant capacity of the alpha-tocopherol incorporated to COC membranes during IVM. The active form of vitamin E during maturation impaired the acquisition of oocyte developmental competence. [source] | |||||||||||||||||||||||||||||||||||||