Percutaneous interventions on the hemodialysis reliable outflow vascular access device.

PURPOSE: To determine the outcomes of percutaneous interventions for prolonging the patency of the Hemodialysis Reliable Outflow (HeRO) device. MATERIALS AND METHODS: Between January 2007 and August 2011, 73 percutaneous interventions were performed on 26 HeRO devices in 25 patients. The graft was implanted in the upper arm with the outflow catheter tip in the superior vena cava or right atrium. Procedural reports, angiographic images, and clinical notes were retrospectively reviewed. The primary and secondary patency rates after intervention were calculated using the Kaplan-Meier method. RESULTS: The mean time from HeRO implantation to initial dysfunction or thrombosis was 171 days. In 60 (82%) procedures, the HeRO device was thrombosed. An intragraft stenosis was the most common lesion identified (59%; n = 43) followed by an arterial anastomosis stenosis identified in 18% (n = 13). In 22% (n = 16) of procedures in which the HeRO device was thrombosed, an underlying cause was not identified after thrombectomy. The 3-, 6-, and 12-month primary patency rates after intervention were 47%, 37%, and 26% for first-time interventions. The secondary patency rates were 80%, 70%, and 64%. The only complication was pulmonary embolism resulting in death 2 days after HeRO thrombectomy. CONCLUSIONS: Percutaneous interventions on thrombosed and failing HeRO devices yielded acceptable primary and secondary patency rates after intervention in these patients with few, if any, alternatives for hemodialysis access.

Central veins of the chest: evaluation with time-resolved MR angiography.

PURPOSE: To retrospectively assess the diagnostic performance of time-resolved magnetic resonance (MR) angiography in the detection of stenoses and occlusions in the central veins of the chest, with angiographic and surgical findings and consensus readings serving as the reference standard. MATERIALS AND METHODS: Institutional review board approval was obtained, and the informed consent requirement was waived for this HIPAA-compliant study. Retrospective analysis was performed with 27 consecutive patients (12 male, 15 female; age range, 16-67 years) who underwent MR venography of the central veins. Six radiologists with varying levels of experience interpreted the studies. For each study, the readers were presented with time-resolved maximum intensity projection (MIP) images only, high-spatial-resolution images only, or both. Sensitivity and specificity were calculated for detection of stenoses and occlusions, as well as for confidence levels, study interpretation time, and determination of the side of the body on which upper extremity contrast material injection was performed. RESULTS: The addition of time-resolved angiographic images to the high-spatial-resolution images resulted in improved specificity in the detection of venous occlusions (0.99 vs 0.96, P = .03), in reader confidence (P < .001), and in the ability to infer the side of injection (83% correct compared with 32% correct, P < .001), without increasing the average time required for study interpretation. Use of time-resolved angiographic data sets as a stand-alone technique had high sensitivity (0.95) but only moderate specificity (0.56) in the detection of venous stenoses or occlusions. CONCLUSION: Time-resolved angiographic images are a useful adjunct to high-spatial-resolution images in the evaluation of central venous stenoses and occlusions.

EGF activates intracellular and intercellular calcium signaling by distinct pathways in tumor cells.

Epidermal growth factor (EGF)-mediated Ca2+ signaling in multiple cell lines derived from human gliomas and in the A431 epidermoid carcinoma cell line was observed using fluorescence videomicroscopy. Bath application of EGF evoked an oscillatory increase in [Ca2+]i in 4 different human glioma cell lines as well as the A431 cell line. This effect was blocked by the EGF receptor tyrosine kinase inhibitors gefitinib and erlotinib, as well as by the EGFR antibody cetuximab. In addition to this acute Ca2+ signaling response, transient exposure to EGF also potentiated subsequent Ca2+ signaling responses to other stimuli. Tumor cells transiently exposed to EGF (5 minutes), showed a sustained increase in propagation of intercellular Ca2+ waves, which have been previously shown to involve release of ATP and activation of purinergic receptors. Cells transiently exposed to EGF also showed a sustained potentiation of the Ca2+ signaling response to ATP. In contrast to the acute Ca2+ signaling response to EGF, this sustained potentiation of purinergic intercellular signaling was not blocked by gefitinib or erlotinib, while it was blocked by cetuximab. These results indicate that while the acute Ca2+ signaling response requires tyrosine kinase activation, the sustained potentiation of intercellular signaling occurs via a distinct pathway. Distinct intra- and intercellular Ca2+ signaling pathways may be mechanisms by which EGF modulates the growth and migration of tumor cells.

The impact of thalamic stimulation on activities of daily living for essential tremor.

BACKGROUND: Deep Brain Stimulation (DBS) of the ventro-intermedius nucleus of the thalamus is the treatment of choice for drug-refractory essential tremor (ET). This study evaluated the effectiveness of thalamic stimulation in improving the patient's quality of life through activities of daily living. METHODS: Sixteen ET patients completed a health questionnaire, the "Tremor Activities of Daily Living Scale" (TADLS) measured by the patient, a 10-item subset of the TADLS measured by the clinician, and the Fahn-Tolosa-Marin tremor rating scale (TRS). Each patient was evaluated with the stimulator on and off with the average evaluation occurring 13 months after surgery. Additionally, improvements on the TADLS were compared to electrode positioning on the axial plane and stimulation parameters. RESULTS: There was a 44.0% improvement in the patient-rated TADLS, a 45.2% improvement in the clinician-rated TADLS, and a 33.9% improvement in the TRS. The average electrode location was 5.65 mm anterior to the posterior commissure (AC-PC), 13.4 mm lateral from the midline, and 2.0 mm below the AC-PC line. The average stimulation parameters were 2.74 Volts, 160 Hertz, and 119 microsec. There was no correlation between improvements on the TADLS, electrode location, and stimulation parameters. Of the 16 patients, 10 patients would repeat the surgery, two were unsure, and four would not repeat the surgery. CONCLUSIONS: Tremor is significantly controlled with DBS and activities of daily living are highly correlated with patient satisfaction. The degree of improvement in the four patients who would not repeat the surgery was outweighed by the negative factors associated with the surgery.