Electrochemical fluorination of La(2)CuO(4): a mild "chimie douce" route to superconducting oxyfluoride materials.

The fluorination of La(2)CuO(4) was achieved for the first time under normal conditions of pressure and temperature (1 MPa and 298 K) via electrochemical insertion in organic fluorinated electrolytes and led to lanthanum oxyfluorides of general formula La(2)CuO(4)F(x). Analyses showed that, underneath a very thin layer of LaF(3) (a few atomic layers), fluorine is effectively inserted in the material's structure. The fluorination strongly modifies the lanthanum environment, whereas very little modification is observed on copper, suggesting an insertion in the La(2)O(2) blocks of the structure. In all cases, fluorine insertion breaks the translation symmetry and introduces a long-distance disorder, as shown by electron spin resonance. These results highlight the efficiency of electrochemistry as a new "chimie douce" type fluorination technique for solid-state materials. Performed at room temperature, it additionally does not require any specific experimental care. The choice of the electrolytic medium is crucial with regard to the fluorine insertion rate as well as the material deterioration. Successful application of this technique to the well-known La(2)CuO(4) material provides a basis for further syntheses from other oxides.

Horner's syndrome after coronary artery bypass surgery.

We established the frequency of Horner's syndrome (HS) in 248 elective patients after coronary artery bypass surgery. Patients were evaluated neurologically pre- and post-operatively and 6 months after surgery. Nineteen patients (7.7%) developed unilateral HS postoperatively, 12 involving the left eye. The finding persisted in 10 patients (4%) at 6 months. When assessed 2 to 6 days, or 6 months, postoperatively, HS tended to be isolated and not associated with C8/T1 plexopathy. Among nondiabetic subjects, hypertensive patients had a higher frequency of HS than normotensive patients (10.6% versus 2.9%, p = 0.05). Among normotensive subjects, diabetic patients had a higher frequency than nondiabetic patients (15% versus 2.9%, p = 0.08). There was no association between HS, age, sex, internal mammary artery grafting, or length of cardiopulmonary bypass time. In summary, HS is a common and sometimes persistent complication of coronary artery bypass surgery. Hypertensive, and possibly diabetic, patients appear to be at greatest risk for developing HS.

Prevalence of anticardiolipin antibody in isolated mitral or aortic regurgitation, or both, and possible relation to cerebral ischemic events.

Anticardiolipin antibodies (acLa) are associated with a thrombotic tendency (often involving cerebral ischemic events), are frequently present with systemic lupus erythematosus and have been found together with cardiac valve abnormalities. Previous studies evaluated patients characterized by the presence of acLa or lupus, precluding assessment of the frequency of acLa in those with valvular disease. This study aims to establish the prevalence of acLa in patients with valve disease in the absence of lupus and, furthermore, to determine the influence of acLa on the risk of cerebral events in valve disease. Eighty-seven consecutive patients with mitral or aortic regurgitation, or both, prospectively underwent enzyme-linked immunosorbent assay testing for immunoglobulin G (IgG) and M acLa, as did 24 normal subjects. AcLa values greater than or equal to 3 SD above the normal mean were considered "positive." Prior cerebral events were defined retrospectively. Of 87 patients with valvular disease, 26 had positive IgG acLa levels compared with 0 of 24 normal subjects (p less than 0.01). AcLa values did not vary with valve disease etiology. Focal cerebral events had occurred in 8 patients and were embolic or probably embolic in 7, including 7 of 26 IgG acLa-positive and 1 of 60 IgG acLa-negative patients (p less than 0.001). In the absence of lupus, IgG acLa is highly prevalent among patients with aortic or mitral regurgitation, or both; this association may indicate a relatively high risk for cerebral emboli.

Particulate emboli capture by an intra-aortic filter device during cardiac surgery.

OBJECTIVE: Particulate embolization is associated with neurologic morbidity after cardiac surgery. Crossclamp manipulation has been identified as the single most significant cause of particulate emboli release during cardiac surgery. A new intra-aortic filtration method has been assessed with regard to its safety and its ability to capture particulate emboli before they enter the central circulation. METHODS: Patients undergoing cardiac surgery with cardiopulmonary bypass through standard median sternotomy were selected for emboli management by means of intra-aortic filtration. A novel intra-aortic filter device was inserted through a modified 24F arterial cannula immediately before releasing the crossclamp in 77 patients. Filters remained in the aorta until cardiopulmonary bypass was discontinued and the heart was fully ejecting. The procedure was assessed for facility, safety, and effect on routine cardiopulmonary bypass operation and function. RESULTS: The insertion and removal of the intra-aortic filter were safe, easy, and uneventful in most patients. Patient hemodynamics and bypass flow rates remained normal throughout the filter dwell period. No strokes or gross neurologic defects were noted. Electron microscopic analysis of 12 filters revealed an insignificant degree of platelet adhesion on filter surfaces. Histology samples (n = 44) were examined, and 66% (n = 29) showed evidence of atheromatous material, 36% (n = 16) with platelet-fibrin, 25% (n = 11) with true thrombus and/or blood clot, 7% (n = 3) with normal vessel wall, and 2% (n = 1) with aggregates of cholesterol or grumous portion of atheromatous plaque. CONCLUSION: The intra-aortic filter can be safely deployed and captures particulate emboli, the predominant origin of which is atheromatous. The beneficial effects of this device on neurologic outcomes have yet to be determined.

Improvement of outcomes after coronary artery bypass. A randomized trial comparing intraoperative high versus low mean arterial pressure.

BACKGROUND: The objective of this randomized clinical trial of elective coronary artery bypass grafting was to investigate whether intraoperative mean arterial pressure below autoregulatory limits of the coronary and cerebral circulations was a principal determinant of postoperative complications. The trial compared the impact of two strategies of hemodynamic management during cardiopulmonary bypass on outcome. Patients were randomized to a low mean arterial pressure of 50 to 60 mm Hg or a high mean arterial pressure of 80 to 100 mm Hg during cardiopulmonary bypass. METHODS: A total of 248 patients undergoing primary, nonemergency coronary bypass were randomized to either low (n = 124) or high (n = 124) mean arterial pressure during cardiopulmonary bypass. The impact of the mean arterial pressure strategies on the following outcomes was assessed: mortality, cardiac morbidity, neurologic morbidity, cognitive deterioration, and changes in quality of life. All patients were observed prospectively to 6 months after the operation. RESULTS: The overall incidence of combined cardiac and neurologic complications was significantly lower in the high pressure group at 4.8% than in the low pressure group at 12.9% (p = 0.026). For each of the individual outcomes, the trend favored the high pressure group. At 6 months after coronary bypass for the high and low pressure groups, respectively, total mortality rate was 1.6% versus 4.0%, stroke rate 2.4% versus 7.2%, and cardiac complication rate 2.4% versus 4.8%. Cognitive and functional status outcomes did not differ between the groups. CONCLUSION: Higher mean arterial pressures during cardiopulmonary bypass can be achieved in a technically safe manner and effectively improve outcomes after coronary bypass.

Posterior distribution of infarcts in strokes related to cardiac operations.

BACKGROUND: Stroke complicates cardiac surgical procedures in a substantial number of patients. The mechanism of stroke is predominantly embolic, although hypoperfusion may play a role. The aim of this study was to determine whether radiologic appearances in this population were consistent with an embolic cause. METHODS: We reviewed computed tomographic scans and medical records in 24 patients who suffered stroke after cardiac operation. Stroke was evident at 24 hours in 19 patients (79%). Infarcts were multiple in 16 and single in 3 patients (group 1). The remaining 5 patients suffered stroke beyond 24 hours and had single infarcts on computed tomographic scan (group 2). RESULTS: In group 1, 15 patients (79%) had bilateral cerebellar infarcts, 4 (74%) had posterior cerebral artery infarcts, 10 (53%) had posterior watershed infarcts, and 11 patients (58%) had middle cerebral artery branch infarcts. The mean number of vascular territories involved was 5.1 (range, 1 to 10). Mobile atheromatous plaque was present in the ascending aorta or arch in 5 of 9 patients (56%) in group 1. In group 2, stroke occurred in close association with atrial or ventricular fibrillation in 3 of 5 patients (60%). CONCLUSIONS: In patients with radiologic evidence of infarction, perioperative strokes after cardiac operation are typically multiple, and involve the posterior parts of the brain, consistent with atheroembolization. Delayed strokes may be attributable to cardiogenic embolism.

Determination of size of aortic emboli and embolic load during coronary artery bypass grafting.

BACKGROUND: Embolic signals have been detected within both the aortic lumen and the intracranial vasculature during coronary artery bypass grafting. Total numbers of these emboli have been reported. The present study examined the size of individual emboli and the total volume of embolization. METHODS: Using transesophageal echocardiography, we continuously monitored the aortic lumen of 10 patients undergoing isolated coronary artery bypass grafting. We manually analyzed 720,000 individual echo frames over a 4-minute period after the release of aortic clamps to track and to calculate the volume of 657 individual particles. The embolic load for the entire procedure was calculated from mean volume based on analysis of 1,508 particles. We simultaneously monitored the middle cerebral artery using transcranial Doppler ultrasonography and compared numbers of emboli detected by the two techniques. RESULTS: Particle diameter ranged from 0.3 to 2.9 mm (mean, 0.8 mm), and particle volume from 0.01 to 12.5 mm3 (mean, 0.8 mm3). Twenty-eight percent of particles measured 1 mm or more, 44% measured 0.6 to 1.0 mm, and only 27% measured 0.6 mm or less in diameter. Aortic embolic load for the procedure ranged from 0.6 cm3 to 11.2 cm3 (mean, 3.7 cm3). Estimated cerebral embolic load for the procedure ranged from 60 to 510 mm3 (mean, 276 mm3). The fraction of aortic emboli entering the cerebral circulation was very variable (3.9% to 18.1%). Seventy-six percent of the embolic volume after the release of clamps occurred over a 20-second period. Only 1 patient was encephalopathic perioperatively. This patient had the largest estimated cerebral embolic load (510 mm3) and the second largest aortic embolic load (8.4 cm3). CONCLUSIONS: We determined the size of individual intraaortic embolic particles and the total volume of embolization during coronary artery bypass grafting, and found the proportion entering the cerebral circulation to be very variable. The constitution of these particles and the neurologic impairment resulting from such embolization remains to be determined.

Impact of embolization during coronary artery bypass grafting on outcome and length of stay.

BACKGROUND: Transcranial Doppler ultrasonography detects emboli in most patients during coronary artery bypass grafting. However, the significance of these emboli has not yet been established. METHODS: We monitored 82 patients during coronary artery bypass grafting with this technique and related the numbers of emboli to the outcomes and length of hospital stay. RESULTS: We detected cerebral emboli in all patients. Patients with stroke (n = 4; 4.9%) had a mean of 449 emboli, as compared with 169 emboli in patients without stroke (n = 78) (p = 0.005). Patients with major cardiac complications (n = 7) had a mean of 392 emboli, as compared with 163 in patients without such complications (n = 75) (p = 0.003). The mean hospital stay of survivors was 8.6 days in patients with fewer than 100 emboli (n = 40), 13.5 days in patients with 101 to 300 emboli (n = 23), 16.3 days in those with 301 to 500 emboli (n = 16), and 55.8 days in patients with more than 500 emboli (n = 6) (p = 0.0007). This relation was unchanged when patients with complications were excluded. The correlation between embolization and outcome was independent of the extent of aortic atheroma or age. CONCLUSIONS: Emboli detected during coronary artery bypass grafting are significantly related to major cardiac and neurologic complications and affect length of stay in all patients, even in the absence of such specific complications.

Aortic atheroma is related to outcome but not numbers of emboli during coronary bypass.

BACKGROUND: The relation between aortic atheroma severity and stroke after coronary artery bypass grafting is established. The relation between atheroma severity and other outcome measures or numbers of emboli has not been determined. METHODS: Using transesophageal echocardiography, we determined the severity of atheroma in the ascending, arch, and descending aortic segments in 84 patients undergoing operations. Seventy patients were monitored using transcranial Doppler ultrasonography. RESULTS: The incidence of stroke was 33.3% among 9 patients with mobile plaque of the arch and 2.7% among 74 patients with nonmobile plaque (p = 0.011). Cardiac complications were not significantly related to atheroma severity in any aortic segment. Length of stay was significantly related to atheroma severity in the aortic arch (p = 0.025) and descending segment (p = 0.024). The presence of severe atheroma in both the arch and descending segments was associated with significantly longer hospital stays as compared with patients with severe atheroma in neither segment (p = 0.05). Numbers of emboli were greater in patients with severe atheroma at clamp placement, although the differences did not achieve statistical significance. CONCLUSIONS: Aortic atheroma severity is related to stroke and to the duration of hospitalization after coronary artery bypass grafting. The lack of correlation between numbers of emboli and atheroma severity suggests that m any emboli may be nonatheromatous in nature.

Substance P in spinal cord dorsal horn decreases following peripheral nerve injury.

Substance P was located in the spinal cord of rats by immunocytochemistry. Section and ligation of the sciatic nerve produced a depleted area low in substance P in the medial two-thirds of laminae 1 and 2 of segments L4 and 5. The time of depletion began about 5 days after the nerve had been cut and substance P reached a steady minimum by about 9 days and remained depleted for the entire period examined, 31 days. Crush lesions of the sciatic nerve failed to produce the marked and rapid changes of spinal cord substance P observed after section and ligation.

The neuroimaging features of the cardiolipin antibody syndrome.

The purpose of our study was to define the neuroimaging features of the cardiolipin antibody syndrome. Thirty-eight patients with elevated anticardiolipin antibody titers were studied with magnetic resonance imaging or computed tomography or both. Two patients underwent cerebral angiography. All patients had recurrent transient ischemic attacks, amaurosis, or strokes. One patient had normal imaging findings. The remaining patients had a combination of infarction and atrophy. Focal infarcts, the most common finding, were seen in 32 patients. Cerebral atrophy was seen in 26 patients and was the only radiographic finding in 5. Angiography demonstrated dramatic abnormalities in the distal portions of the anterior and posterior circulations, with multiple stenosis and occlusions and extensive pial and transdural collateral networks. The cardiolipin antibody syndrome should be suspected in young patients with transient ischemic attacks or strokes in the absence of the usual risk factors for cerebrovascular disease. The presence of raised anticardiolipin antibody titers or the cardiolipin antibody syndrome in patients with lupus, in those with other connective tissue diseases, and in patients without overt manifestations of an autoimmune disorder should be viewed as a risk factor for future ischemic cerebrovascular events. Further understanding of the precise role of these antibodies in the pathogenesis of vascular thrombosis may lead to a better understanding of the mechanisms underlying certain forms of stroke.

Cerebral complications in cardiac surgery: the role of embolization and hypoperfusion.

Cardiac surgery is currently performed on 800,000 patients each year worldwide. Complications involving the central nervous system account for the major adverse sequelae of the procedure and are increasing substantially as more elderly patients are undergoing surgery. Strokes occur in 5% of patients undergoing coronary artery bypass grafting (CABG), and in as many as 13% of patients undergoing open heart surgery. Neuropsychologic impairment occurs more commonly and is persistent in 35% of patients 1 year after surgery.

Cerebral complications in cardiac surgery: changing concepts and technologic advances.

Coronary artery bypass surgery is an effective treatment for patients with multivessel coronary artery disease. The overall mortality and cardiac morbidity associated with the procedure has progressively declined since the early days, mostly attributable to improvements in surgical and anesthetic techniques. Over the same period, however, the average age of patients undergoing surgery has risen considerably, and with it, the incidence of neurologic complications. Currently, neurologic complications are the leading cause of morbidity associated with the procedure, and death due to neurologic causes has increased from 7% to 20% of all deaths. These complications are reflected in prolonged hospitalization of patients, at dramatic cost both to the patient and to the health system as a whole.

Safety and feasibility of nasopharyngeal evaporative cooling in the emergency department setting in survivors of cardiac arrest.

AIM: Mild therapeutic hypothermia improves survival and neurologic recovery in primary comatose survivors of cardiac arrest. Cooling effectivity, safety and feasibility of nasopharyngeal cooling with the RhinoChill device (BeneChill Inc., San Diego, USA) were determined for induction of therapeutic hypothermia. METHODS: Eleven emergency departments and intensive care units participated in this multi-centre, single-arm descriptive study. Eighty-four patients after successful resuscitation from cardiac arrest were cooled with nasopharyngeal delivery of an evaporative coolant for 1h. Subsequently, temperature was controlled with systemic cooling at 33 degrees C. Cooling rates, adverse events and neurologic outcome at hospital discharge using cerebral performance categories (CPC; CPC 1=normal to CPC 5=dead) were documented. Temperatures are presented as median and the range from the first to the third quartile. RESULTS: Nasopharyngeal cooling for 1h reduced tympanic temperature by median 2.3 (1.6; 3.0) degrees C, core temperature by 1.1 (0.7; 1.5) degrees C. Nasal discoloration occurred during the procedure in 10 (12%) patients, resolved in 9, and was persistent in 1 (1%). Epistaxis was observed in 2 (2%) patients. Periorbital gas emphysema occurred in 1 (1%) patient and resolved spontaneously. Thirty-four of 84 patients (40%) patients survived, 26/34 with favorable neurological outcome (CPC of 1-2) at discharge. CONCLUSIONS: Nasopharyngeal evaporative cooling used for 1h in primary cardiac arrest survivors is feasible and safe at flow rates of 40-50L/min in a hospital setting.

NT69L, a novel analgesic, shows synergy with morphine.

BACKGROUND: Neurotensin (NT) is a neuropeptide with antinociceptive effects that are mediated through NT receptors, of which there are three known subtypes (NTS1, NTS2, and NTS3). Morphine is a mu-opioid receptor agonist commonly used for pain treatment but is associated with side effects that can be serious. We hypothesize that selective NT receptor agonists may represent a novel class of analgesics and their use in conjunction with morphine will have synergistic properties which may reduce the dose of morphine administered and its side effects. METHODS: The antinociceptive activity of an NT agonist (NT69L) and morphine was studied in rats using the hot plate test to determine if there is synergism between the two drugs in reducing pain. The NTS2 receptor antagonist, levocabastine, was used to determine the receptor subtype involved in the analgesic effect of NT69L and morphine. RESULTS: The administration of both NT69L and morphine resulted in a dose-dependent analgesic effect. The isobolographic analysis demonstrated that the combination of sub-analgesic doses of NT69L and morphine was synergistic in the hot plate test. Pretreatment with the NTS2 receptor antagonist, levocabastine attenuated the antinociceptive effect of NT69L and the combined effect of NT69L and morphine in the hot plate test. CONCLUSION: The results support the hypothesis that the synergistic combination of NT69L and morphine would improve the pharmacological treatment of pain while minimizing specific adverse effects of each of the drugs at a higher dose. NTS2 is important for the antinociceptive effect of NT69L and morphine.

Aortic atheromatosis and risks of cerebral embolization.

With the advent of transesophageal echocardiography, aortic atheromatosis has emerged as an important source of cerebral embolization. Mobile atheromatous plaque in the ascending aorta and aortic arch has been shown to constitute a strong and independent risk factor in patients with stroke. In patients undergoing coronary bypass surgery, it is the single most important contributing factor to perioperative neurologic morbidity. Emboli originating in the heart, aorta, and proximal cerebral vasculature have been observed intraoperatively in patients undergoing coronary bypass surgery, especially when aortic clamps are released. The constitution of these emboli is unclear, although an indeterminate fraction undoubtedly represents dislodged atheromatous material. The impact of such embolization in terms of neurologic outcome is currently under investigation. Prevention of embolization from mobile aortic atheroma in patients undergoing cardiac surgery may require modification of surgical technique. Secondary prevention in patients with a history of embolization can only be determined once the natural history of such lesions is established.

Disturbances in conceptual space involving language and speech.

We report on a patient, with a CT-verified low density lesion in the right parietal area, who exhibited not only deficits in left conceptual space, but also in reading, writing, and the production of speech. He presented with a left homonymous hemianopia, tactile inattention, and dysphasia that quickly resolved, leaving a left-sided inattention and less marked dysphasia. Several language tasks and language-based imagery tasks revealed poor language processing of the left portion of words which could be remedied if the patient was instructed to do things like spell the word backwards. The overall results were consistent with the idea that some aspects of language processing involve spatial mechanisms.

Neurologic complications of cardiac surgery.

The average age of patients undergoing cardiac surgery and the number of comorbidities they possess will continue to increase as surgical technology advances. Toxic/metabolic encephalopathy, hemispheric strokes, hypoxic injury, and peripheral nerve lesions all can occur as a result of cardiac surgery. Therefore, an understanding of the neurologic risk, recognizable syndromes, and preventative measures will continue to be important. Careful preoperative assessment, operative risk factor reduction, and careful postoperative assessments and management may reduce the neurologic risk for cardiac surgery.

Anticardiolipin antibody and stroke: possible relation of valvular heart disease and embolic events.

To establish the etiology of strokes related to the anticardiolipin antibody (Acla) syndrome and to determine the relationship of valvular heart disease and stroke in the presence of the Acla, clinical and objective characteristics of 21 patients with Acla, focal cerebral ischemic events were retrospectively analyzed. Twelve (86%) of 14 patients with stroke and 3 (42%) of 7 patients with non-stroke cerebral ischemic events had echocardiographic evidence of left-sided valvular abnormalities. Features characteristic of cardioembolic stroke were present in 12 (86%) of the 14 patients with stroke. The strength of the association between valvular disease and stroke, combined with the clinical and radiologic features noted, suggest that strokes related to the Acla syndrome typically are embolic, from a cardiac source.