Transluminal angioplasty of the vertebral and basilar artery

Transluminal angioplasty of brachiocephalic vessels for atherosclerotic lesions is now being performed in selected cases. We have thus far treated 17 cases of vertebral artery stenosis and one case of basilar artery stenosis by intravascular balloon dilatation techniques. Clinical presenting symptoms included vertebral basilar insufficiency, repeated transient ischemic attacks (TIAs), and multiple strokes. We performed successful transluminal angioplasty in 16 patients with marked narrowing (greater than 70%) of the dominant vertebral artery from atherosclerosis. One patient with basilar artery stenosis with tandem atherosclerotic lesions was also treated by angioplasty techniques. Repeat angiography at 3- to 12-month intervals has revealed continued patency at the angioplasty site. Complications occurred in our one patient with basilar artery angioplasty, who suffered a brainstem infarction after treatment, and in one patient who had a TIA after bilateral vertebral artery angioplasty. Two other patients had residual vertebral stenosis but remained asymptomatic after the procedure. All other patients who had successful dilatation were asymptomatic at 6 months to 2 years (mean, 15 months) of follow-up. These initial studies indicate that vertebral artery angioplasty may be effective for treating high-grade atherosclerotic lesions and for improving blood flow to the posterior circulation. Angioplasty of the basilar artery is technically more difficult and has a higher degree of risk because of the many perforating branches supplying the brainstem.     

Carotid cavernous fistulae: indications for urgent treatment

Angiographic and clinical data from 155 patients with carotid cavernous fistulae were retrospectively reviewed to determine angiographic features associated with increased risk of morbidity and mortality. These features included presence of a pseudoaneurysm, large varix of the cavernous sinus, venous drainage to cortical veins, and thrombosis of venous outflow pathways distant from the fistula. Clinical signs and symptoms that characterized a hazardous carotid cavernous fistula included increased intracranial pressure, rapidly progressive proptosis, diminished visual acuity, hemorrhage, and transient ischemic attacks. Cortical venous drainage from the carotid cavernous fistula is secondary to occlusion or absence of the normal venous outflow pathways and is associated with signs and symptoms of increased intracranial pressure and an increased risk of intraparenchymal hemorrhage. Angiographic demonstration of a cavernous sinus varix, with extension of the sinus into the subarachnoid space, is associated with an increased risk of fatal subarachnoid hemorrhage. Identification of these high-risk features provides a basis for making decisions about treatment.     

Platinum wire: a new transvascular embolic agent

Standard Gianturco and "mini" coils cannot be used with some of the present microcatheter systems. However, occasions arise in which metallic coils would be an ideal embolic agent in vascular structure accessible only to a tracker (2.2-French) catheter system. We performed nine embolization procedures in eight patients with arteriovenous fistulas using platinum coils as an embolic agent. Fistulas were completely occluded in six of the nine cases. In several cases, platinum wire embolization was augmented with other agents. Complications occurred in two cases, neither resulting in permanent neurologic deficits. Advantages of using platinum coils included availability, radioopacity, thrombogenicity, biocompatibility, and delivery through microcatheters, specifically the tracker catheter system.     

Flat crossed-coil detector for blood flow measurement using nuclear magnetic resonance

A new flat crossed-coil nuclear magnetic resonance (n.m.r.) detector can be used to measure flood flow at many regions of the body, is introduced. It is compared, bothin vitro andin vivo, with the already proven cylindrical crossed-coil n.m.r. detector. Both detectors use a single high-field homogenous magnet. A single-sideband receiver reduces the effect of transmitter leakage into the receiver coil to allow the use of a high-level transmitter field. Preliminary application of the flat crossed-coil detector to the detection of cerebral blood flow is presented.     

Teaching medical students about medical errors and patient safety: evaluation of a required curriculum.

PURPOSE: To assess the effectiveness of a brief curriculum about patient safety and medical errors with third-year medical students. METHOD: From 2000-03, third-year medical students at New York Medical College, Valhalla, New York, were required to participate in a new curriculum on patient safety and medical errors during their family medicine clerkships. Five hundred seventy-two students participated in a four-hour curriculum that included interactive discussion, readings, a videotape session with a standardized patient, and a small-group debriefing facilitated by a family physician. Before and after participating in the curriculum, students were asked to complete questionnaires on self-awareness about patient communication and safety. Curriculum evaluations and follow-up surveys were also distributed. Responses to each statement on the before and after questionnaires were compared using the Wilcoxon signed-rank test for matched data. RESULTS: Five hundred eleven (89%) students reported that the opportunity to present an error to a patient increased their confidence about discussing this issue with patients, and 537 (94%) students reported that they strongly agreed or agreed that the standardized patient and feedback exercise was a useful learning experience. A total of 535 before and after questionnaires were used in the analysis. A comparison of before and after questionnaire data revealed statistically significant increases in the self-reported awareness of students' strengths and weaknesses in communicating medical errors to patients (p 相似文献   

Spinal dural arteriovenous fistula with an associated feeding artery aneurysm: case report

OBJECTIVE AND IMPORTANCE: A case of a spinal dural arteriovenous fistula (DAVF) with two associated feeding artery aneurysms is reported. Intradural spinal arteriovenous malformations have been associated with aneurysms that present with subarachnoid hemorrhage and with venous varices that produce mass effect, but spinal DAVFs have not previously been described in association with feeding artery aneurysms. CLINICAL PRESENTATION: A 71-year-old man presented with progressive spastic paraparesis, constipation, and overflow incontinence. Magnetic resonance imaging demonstrated a spinal vascular lesion and venous ischemia in the lower spinal cord. Diagnostic spinal angiography revealed a DAVF originating from the left T11 radicular artery and having the unusual feature of two proximal feeding artery aneurysms. INTERVENTION: The patient deteriorated neurologically after undergoing angiography, prompting emergent surgery. The DAVF was resected through a T11 transpedicular approach. One aneurysm was dolichoectatic and therefore unclippable, requiring proximal occlusion of the parent artery after establishing tolerance of test occlusion using somatosensory evoked potentials; the second aneurysm was adjacent to the fistula and was resected with the DAVF. CONCLUSION: Feeding artery aneurysms in association with spinal DAVFs have not been previously reported. They present additional risk to patients and, with simple modifications of the standard operative approaches, can easily be treated as part of the surgery for the DAVF.     

Cell Type-specific Effects of the Neural Adhesion Molecules L1 and N-CAM on Diverse Second Messenger Systems

We have previously shown that the neural adhesion molecules L1 and N-CAM influence second messenger systems when triggered with specific antibodies at the surface of the phaeochromocytoma PC12 cell line (Schuch et al., Neuron, 3, 13 - 20, 1989). To determine whether the two molecules are linked to the same intracellular signalling cascades, independent of the cell type expressing them, or whether different neural cell types respond with different signal transduction mechanisms, we have investigated the effects of antibodies to L1 and N-CAM, and the isolated molecules themselves, on second messenger systems in different neural cell types. We have investigated cultures of cerebellar and dorsal root ganglion neurons and transformed Schwann cells and related these results to those obtained with the PC12 cell line. Here we show that addition of L1 and N-CAM antibodies and the isolated molecules themselves elicit cell type-specific responses that can be modulated by the substrate on which the cells are maintained. Depending on the cell type, cells respond to the triggering of L1 and N-CAM with antibodies, or addition of the purified molecules, by either up-regulation or down-regulation of inositol phosphate turnover, by a rise in intracellular Ca2+ levels dependent on or independent of the opening of voltage-gated Ca2+ channels, or by an increase or decrease in intracellular pH. Moreover, cerebellar neurons expressing N-CAM respond to addition N-CAM, but not to N-CAM antibodies, in contrast to the other neural cell types studied, which respond to both triggers. Furthermore, cerebellar neurons were the only cells to show a rise in cAMP levels in response to any of the ligands tested. This stimulation of cAMP production by L1 antibodies depended on the cross-linking of L1 molecules at the cell surface, whereas the other responses did not depend on clustering of L1. Simultaneous addition of L1 and N-CAM antibodies either elicited an additive or more than additive effect on the intracellular responses which, for cerebellar neurons, depends on the substrate on which the cells are maintained. These observations indicate that L1 and N-CAM or their antibodies activate cell type-specific intracellular signalling systems and that the two molecules can act interdependently or independently of each other.     

Time-course of the electrophysiological maturation and integration of transplanted cardiomyocytes

Electrophysiological maturation and integration of transplanted cardiomyocytes are essential to enhance safety and efficiency of cell replacement therapy. Yet, little is known about these important processes. The aim of our study was to perform a detailed analysis of electrophysiological maturation and integration of transplanted cardiomyocytes. Fetal cardiomyocytes expressing enhanced green fluorescent protein were transplanted into cryoinjured mouse hearts. At 6, 9 and 12days after transplantation, viable slices of recipient hearts were prepared and action potentials of transplanted and host cardiomyocytes within the slices were recorded by microelectrodes. In transplanted cells embedded in healthy host myocardium, action potential duration at 50% repolarization (APD50) decreased from 32.2±3.3ms at day 6 to 27.9±2.6ms at day 9 and 19.6±1.6ms at day 12. The latter value matched the APD50 of host cells (20.5±3.2ms, P=0.78). Integration improved in the course of time: 26% of cells at day 6 and 53% at day 12 revealed no conduction blocks up to a stimulation frequency of 10Hz. APD50 was inversely correlated to the quality of electrical integration. In transplanted cells embedded into the cryoinjury, which showed no electrical integration, APD50 was 49.2±4.3ms at day 12. Fetal cardiomyocytes transplanted into healthy myocardium integrate electrically and mature after transplantation, their action potential properties after 12days are comparable to those of host cardiomyocytes. Quality of electrical integration improves over time, but conduction blocks still occur at day 12 after transplantation. The pace of maturation correlates with the quality of electrical integration. Transplanted cells embedded in cryoinjured tissue still possess immature electrophysiological properties after 12days.