First fast-ion D-alpha (FIDA) measurements and simulations on C-2U.

The first measurements of fast-ion D-alpha (FIDA) radiation have been acquired on C-2U, Tri Alpha Energy's advanced, beam-driven field-reversed configuration (FRC). These measurements are also forward modeled by FIDASIM. This is the first measurement and simulation of FIDA carried out on an FRC topology. FIDA measurements are made of Doppler-shifted Balmer-alpha light from neutralized fast ions using a bandpass filter and photomultiplier tube. One adjustable line-of-sight measured signals at eight locations and eight times during the FRC lifetime over 26 discharges. Filtered signals include only the highest energy ions (>6 keV) and share some salient features with the FIDASIM result. Highly Doppler-shifted beam radiation is also measured with a high-speed camera and is spatially well-correlated with FIDASIM.

Effects of anisotropic thermal conductivity in magnetohydrodynamics simulations of a reversed-field pinch.

A compressible magnetohydrodynamics simulation of the reversed-field pinch is performed including anisotropic thermal conductivity. When the thermal conductivity is much larger in the direction parallel to the magnetic field than in the perpendicular direction, magnetic field lines become isothermal. As a consequence, as long as magnetic surfaces exist, a temperature distribution is observed displaying a hotter confined region, while an almost uniform temperature is produced when the magnetic field lines become chaotic. To include this effect in the numerical simulation, we use a multiple-time-scale analysis, which allows us to reproduce the effect of a large parallel thermal conductivity. The resulting temperature distribution is related to the existence of closed magnetic surfaces, as observed in experiments. The magnetic field is also affected by the presence of an anisotropic thermal conductivity.

Compressibility effects in the dynamics of the reversed-field pinch.

We study the reversed-field pinch through the numerical solution of the compressible magnetohydrodynamic equations. Two cases are investigated: In the first case the pressure is derived from an adiabatic condition, and in the second case the pressure equation includes heating terms due to resistivity and viscosity. In the adiabatic case a single helicity state is observed, and the reversed-field pinch configuration is formed for short time intervals and is finally lost. In the nonadiabatic case the system reaches a multiple helicity state, and the reversal parameter remains negative for a longer time. The results show the importance of compressibility in determining the large scale dynamics of the system.

Evolution of anisotropic turbulence in nonlinear magnetic reconnection.

The anisotropy properties of magnetohydrodynamic turbulence in a sheared magnetic field are analyzed through a three-dimensional numerical simulation that reproduces the linear and nonlinear stage of a tearing instability. Far from the current sheet, the energy spectrum develops perpendicularly to the local magnetic field, as in homogeneous configurations. Within the current sheet, the spectrum anisotropy is also affected by the structure of unstable modes. With increasing time, the configuration becomes more turbulent, the former effect disappears, and the energy cascade takes place perpendicularly to the local magnetic field. The local spectrum becomes increasingly anisotropic while the spatially integrated spectrum tends to isotropize. There is the possibility that these properties could be used to identify the nonlinear stage of magnetic reconnection in space and laboratory plasmas, as well as to identify the particle transport regime in the considered magnetic configuration.

Hearing results of ossiculoplasty in Austin-Kartush group A patients.

OBJECTIVE: To compare hearing results in patients who underwent ossiculoplasty for Austin-Kartush group A impairments (incus erosion, malleus handle present, stapes superstructure present) with the results in patients with an intact ossicular chain who required only myringoplasty. The literature on hearing results of ossiculoplasty with different types of prostheses and different techniques is reviewed. PATIENTS AND STUDY DESIGN: This study retrospectively reviews a series of 181 consecutive ossiculoplasties and 204 consecutive myringoplasties. SETTING: The study was carried out partly at a private practice and partly in an academic tertiary referral center. MAIN OUTCOME MEASURES: This study complies with levels 1 and 2 of the guidelines recommended by the American Academy of Otolaryngology--Head and Neck Surgery (1995). RESULTS: When success was defined as a postoperative air-bone gap within 10 dB, the success rate was higher for myringoplasty (81%) than for ossiculoplasty (55%). When success was defined as a postoperative air-bone gap within 20 dB, the success rate was 97% in myringoplasties and 85% in ossiculoplasties. There was no significant deterioration over time of the mean postoperative air-bone gap for any frequency. CONCLUSION: Cumulative data from several authors show that -50% of patients undergoing partial ossiculoplasty have a postoperative air-bone gap of 0 to 10 dB, and 80% have a postoperative air-bone gap of 0 to 20 dB. Equally good results may be achieved with autograft (no difference was found between interposition of the incus or the head of the malleus), homograft, or alloplastic partial prostheses. With alloplastic total prostheses, 36% of patients have a postoperative air-bone gap of 0 to 10 dB, and 74% have a postoperative air-bone gap of 0 to 20 dB.

Transcatheter closure of patent foramen ovale in patients with cryptogenic stroke.

BACKGROUND: About 50% of patients with cryptogenic stroke have a patent foramen ovale (PFO). The recurrence rate of paradoxical embolism is higher if a PFO is detected. METHODS: Thirty-five patients with PFO and > or = 1 thromboembolic event due to paradoxical embolism were included in the study (23 males, 12 females, mean age 47.8 +/- 14 years, mean weight 75 +/- 15 kg). Twenty-three patients had a transient ischemic attack whereas 12 experienced an ischemic stroke. Twenty-nine patients had one thromboembolic event, 4 patients had two thromboembolic events, and 2 patients had three thromboembolic events. The implantation procedure was performed, as previously reported, under general anesthesia, fluoroscopic guidance and during transesophageal echocardiography. RESULTS: The implantation procedure was successful in all patients. There were no complications related to the procedure. Four different devices were implanted (Amplatzer 3 patients; Cardioseal 12 patients; Starflex 12 patients, PFO Star 8 patients). The procedure time and fluoroscopic time were 50 +/- 21.8 and 12.2 +/- 8.3 min respectively. At transesophageal echocardiography performed after the procedure, 11 patients had a trivial shunt. None of the patients had a residual shunt at 1 month of follow-up. The mean follow-up was 12.3 +/- 8 months (median 11.0 months, range 3-37 months). In no patient did recurrence of a thromboembolic event occur during follow-up. CONCLUSIONS: Percutaneous PFO closure is a feasible and safe technique for the prevention of recurrent paradoxical embolism.

Italian BiodivYsio open registry (BiodivYsio PC-coated stent): study of clinical outcomes of the implant of a PC-coated coronary stent.

UNLABELLED: Rapid technological developments have made new materials available for percutaneous coronary intervention procedures. The coronary stent in particular has undergone progressive structural improvements leading to the recent availability of a third generation of stents, namely, coated stents. The rapid evolution of the stent has often made its evaluation problematical, since trials are frequently confined to small groups of patients in single centers. The purpose of this registry was to verify the safety and efficacy of the BiodivYsio stent (a stent coated with phosphorylcholine polymer) in a broad population of patients who reflect the daily reality of coronary intervention in a cardiac catheterization laboratory. METHODS AND RESULTS: The registry was designed to collect the principal angiographic and clinical data of a consecutive series of Oreal worldO patients. Patients were treated with a BiodivYsio stent (Biocompatibles, Galway, United Kingdom) in 12 centers (11 Italian and 1 Swiss) between January 1998 and January 1999. Procedural, in-hospital, 30-day and six-month follow-up data were collected. The monitoring, data entry and statistical analyses were carried out by an independent center. During the study, 218 patients were enrolled; 165 (76%) male and 53 (24%) female, with an average age of 61.6 +/- 9.4 years (range, 36Eth 84 years). A total of 258 stents were implanted in 233 lesions (1.1 stents per lesion), of which 233 (90%) were the BiodivYsio PC coated stent, the remaining 25 implants were of other stent types. The percutaneous transluminal coronary angioplasty and stenting procedure were carried out in 109 (50%) patients with unstable angina, 65 (30%) with stable angina, 29 (13%) with acute myocardial infarction, and 15 (7%) patients with silent ischemia. Procedural success was achieved in 217/218 (99.5%) patients. Optimal results were achieved in 212 (97.7%) patients. In 34 (15.6%) cases, patients were treated with periprocedural abciximab. During the hospitalization period, one (0.4%) death occurred on day 7 due to subacute occlusion of the stent, and 3 (1.4%) myocardial infarctions were reported. At 30-day follow-up, 211 (97.2%) patients were asymptomatic, as were 189 (87%) patients at clinical follow-up at 6 months. CONCLUSIONS: This study evaluated the safety and efficacy of a third-generation stent. The results demonstrate a high procedural success rate and a low incidence of major adverse cardiac events at short- and medium-term follow-up. It appears that the BiodivYsio stent should be considered safe in clinical and/or anatomical situations with a high risk of complications, confirming the hypothesis that PC may have non-thrombogenic properties. To corroborate these results, an appropriately designed study would be required to measure the stentOs efficacy in the most suitable clinical context, i.e., clinical situations that are at the highest risk of ischemic relapse.

Isolation and characterization of neural stem cells from the adult human olfactory bulb.

We have recently isolated stem cells deriving from the olfactory bulbs of adult patients undergoing particularly invasive neurosurgery. After improving our experimental conditions, we have now obtained neural stem cells according to clonal analysis. The cells can be expanded, established in continuous cell lines and differentiated into the three classical neuronal phenotypes (neurons, astrocytes, and oligodendrocytes). Also, after exposition to leukemia inhibitory factor, we are able to improve the number of neurons, an ideal biological source for transplantation in various neurodegenerative disorders.

Comparison of long-term hearing results after vestibular neurectomy, endolymphatic mastoid shunt, and medical therapy.

OBJECTIVE: This study aimed to compare the hearing changes in the long term after vestibular neurectomy, endolymphatic mastoid shunt, and medical treatment in classic Meniere's disease. STUDY DESIGN: A retrospective case review was conducted based on audiologic follow-up between 5 and 21 years. SETTING: The study was performed at two centers in Bari University Hospital, one performing vestibular neurectomy as the first surgical procedure for Meinere's disease and the other, endolymphatic mastoid shunt. PATIENTS AND INTERVENTIONS: Of 68 patients with intractable idiopathic Meniere's disease, 29 underwent middle fossa vestibular neurectomy, and 17 had endolymphatic mastoid shunt; 22 were offered surgery but declined. MAIN OUTCOME MEASURES: Outcome measures were puretone average (PTA), speech reception threshold, and speech discrimination score before and after treatment. RESULTS: PTA declined by an average of 9.3 dB in neurectomy patients, 13.3 dB in patients undergoing endolymphatic mastoid shunt, and 18.1 dB in patients who were offered surgery but declined. Patients were subdivided into two cohorts based on their preoperative or initial PTA. In the patients who had PTA scores worse than 50 dB initially, the PTA declined an average of 4.3 dB in the vestibular neurectomy group, 11.5 dB in the endolymphatic sac group, and 4 dB in the nonsurgical group. In the patients with PTA > or = 50 dB initially, the PTA declined an average of of 25.3 dB in the vestibular neurectomy group, 16.1 in the endolymphatic sac group, and 26.2 dB in the nonsurgical group. Although shunt patients with good hearing initially deteriorated less than neurectomy patients and less than patients who declined surgery, the difference was not significant. CONCLUSIONS: These results indicate that patients with poor hearing stabilized, while patients with good hearing continued to deteriorate. The same conditions were observed in the patients who had surgery and those who were offered surgery but declined.

Factors affecting the therapeutic choice in patients with multivessel coronary artery disease. The Studio Lombardo Angiografia Multivasali (SLAM) Study Group.

OBJECTIVE: To assess how clinical and angiographic findings are related to the decision to carry out coronary angioplasty (PTCA) or coronary bypass grafting in patients with multivessel coronary artery disease. DESIGN: Prospective survey carried out in 14 centres in the Lombardia region of Italy. PATIENTS: 1468 consecutive patients under going coronary arteriography for known or suspected ischaemic heart disease between May and October 1994, who were found to have multivessel coronary artery disease. MAIN OUTCOME MEASURES: Multivariate analysis was undertaken using stepwise logistic regression to identify the clinical and angiographic variables correlated with revascularisation (v medical treatment) in all of patients, and with surgery (v angioplasty) in the subset of revascularised patients. RESULTS: In all patients the clinical decision after coronary arteriography was made by physicians of each participating centre on the basis of their experience and clinical judgment: 53% of patients had bypass surgery, 28% had PTCA, and 19% continued medical treatment. The choice of a revascularisation procedure was directly related to a clinical diagnosis of unstable angina (P < < 0.001), the presence of left anterior descending artery disease (P < < 0.001), and to an ejection fraction > or = 40% (P < < 0.001), and inversely related to history of previous coronary bypass surgery (P < < 0.001). In revascularised patients, bypass surgery was the preferred treatment in patients with left anterior descending artery disease (P < < 0.001), three-vessel disease (P < < 0.001), and in those with at least one occluded vessel (P = 0.008). The choice of PTCA was significantly related to history of previous PTCA (P < < 0.001) or coronary bypass surgery (P < < 0.001), to a clinical diagnosis of non-Q wave myocardial infarction (P = 0.002), and to the possibility of implanting an intracoronary stent (P = 0.01). CONCLUSIONS: Bypass surgery is still the most widely used treatment for patients with multivessel coronary artery disease. This analysis provides a basis for comparison with future developments in the treatment of such patients. Further advancements in PTCA technology are needed to tilt the balance in favour of this less invasive procedure.

Stenting of the Infarct-Related Artery During Complicated Angioplasty in Acute Myocardial Infarction.

The aim of this study was to assess safety and efficacy of coronary stenting as a strategy for improving PTCA suboptimal angiographic result. From March 1993 to December 1995, 104 patients underwent PTCA during acute myocardial infarction. Unplanned coronary stenting was required in 66 pts (63.5%). Procedural success was obtained in 64 pts (97%). Two patients had an unsuccessful stenting procedure: one patient for a suboptimal stent deployment and another for LAD reocclusion requiring emergency CABG (1.5%). Palmaz-Schatz stents were used in 60 pts (91%) and AVE micro-stent in 6 pts (9%). During the hospital course, subacute reocclusion of the vessel occurred in 3 pts (4.6%); one patient underwent a successful rePTCA while the other two underwent CABG. Two patients had vascular groin complications requiring surgical repair of the femoral artery. During hospitalization, one patient underwent elective CABG for early residual myocardial ischemia. At seventy-two hours from PTCA, one patient (1.5%) died as a result of intestinal infarct. Six months survival rate was 98.3% for 59 pts discharged alive from our department. Ten pts were symptomatic during the follow-up: One patient underwent PTCA on another vessel and the other underwent CABG for a multivessel disease. CABG was used in one patient who presented residual silent ischemia in multivessel coronary artery disease. At six months, the first group of patients (18 pts) underwent planned coronary angiography: Vessel patency was present in 17 patients. One patient had an asymptomatic reocclusion of the treated vessel. This study shows a good angiographic result obtained with intracoronary stenting during primary or rescue PTCA of the infarct-related artery. It does not appear to increase major in-hospital adverse events and may reduce the need for surgical revascularization, reducing in-hospital mortality rate and favorably affecting LVEF.

Long-term follow-up after middle fossa vestibular neurectomy for Ménière's disease.

Thirty-seven patients operated on by total vestibular neurectomy for Ménière's disease underwent follow-up examination for at least 5 years. Vertigo has been controlled in all the patients excepting one who developed Ménière's disease in the opposite ear. Three patients had a total hearing loss. Overall results in this study are comparable to those of other series in the literature. Vestibular neurectomy has been confirmed to be an effective procedure for relieving vertigo in intractable Ménière's disease with a success rate of 90-100% while preserving hearing in most of the patients. The results of vestibular neurectomy are far better than those obtainable with endolymphatic sac surgery.

Interdisciplinary treatment of spina bifida children.

In the Spina Bifida Centre, Niguarda Ca' Granda Hospital (Milan, Italy), from June 1985 to June 1990, 60 spina bifida children have been treated. The results of the rehabilitation programme (including orthopaedic, urological and psychosocial aspects) at the time of the survey were: (a) Neuromotor function: 72% of the patients achieved ambulation, 52% of these being less than 2 years of age, and 20% older than 2 years; 18% were too young for walking. Thus, considering the children's age, about 90% of the subjects achieved the standing position, and 89% achieved ambulation. (b) Bladder function: 83% of the children had a complete urological evaluation; 40% of those with a neuropathic bladder had a hyperreflex type, 54% areflexic, and 6% normoreflexic. Thirty-two percent of the patients had signs of 'high pressure' bladder function. Urinary continence was: 36% > or = 2 hours, 20% < 2 hours, 44% not detectable (age < 2 years). Forty percent of the subjects used intermittent catheterisation. (c) Psychosocial aspect: child adaptation to the disease and to the rehabilitation programme was good in 61% of the patients; family problems were identified in 70% of the patients; enrollment in preschool and school programmes was normal (or with specialist teaching) in about 74%; 33.3% of the subjects had disturbance of affect. The results clearly showed that the interdisciplinary approach favoured the social integration of these children.

Very far-advanced otosclerosis.

The term very far-advanced otosclerosis is proposed to indicate otosclerotic patients with both bone and air conduction thresholds nonmeasurable on a standard clinical audiometer (blank audiogram). Three of these patients have undergone stapedotomy with satisfactory results. This confirms that cochlear implantation is not the best treatment for all profoundly deaf patients at least with implants available today. Some of the patients with a blank audiogram are better off with exploratory tympanotomy and stapedotomy.

Reliability of standard apexcardiography for the measurement of sudden variations in mean pulmonary capillary wedge pressure.

We simultaneously registered the left apexcardiogram together with the left intraventricular pressure curve immediately before and after ventricular angiography in order to evaluate whether the relation existing between apexcardiographic protodiastolic filling period duration (cR interval) and left ventricular mean diastolic pressure (LVMDP) was maintained even in the presence of sudden variations of LVMDP. Administration of contrast media resulted in a significant increase of LVMDP (from 11.8 to 23.9 mm Hg) and in a simultaneous decrease of the cR interval (from 108.5 to 71.0 msec) and noninvasive LVMDP calculated as 36-0.24* cR closely correlated with the invasive values both before and after angiography (overall correlation r = 0.94). Apexcardiography thus confirms to be the only highly reliable noninvasive technique which can be used by the clinical cardiologist to measure LVMDP and/or mean pulmonary capillary wedge pressure.

Management of complicated coronary angioplasty by intracoronary urokinase and immediate re-angioplasty.

Percutaneous transluminal coronary angioplasty was complicated by acute coronary occlusion, dissection of the arterial wall, or angiographic evidence of intraluminal thrombosis in 33 high-risk patients from 153 consecutive angioplasty procedures (21.5%). Ten patients (group I) were managed with nitroglycerin (0.2 to 0.4 mg i.c.) and repeated attempts at mechanical guide wire recanalization or dilation, but they did not receive thrombolytic therapy. In the remaining 23 patients (group II), intracoronary urokinase (100,000 to 360,000 U.I.) was administered over 15-20 min after onset of coronary occlusion or thrombosis and continued during attempts at repeated dilation of the stenosis. The incidence of sudden coronary artery occlusion was 70% in group I patients and 52% in group II. The angiographic evidence of thrombus formation was observed in a higher, but not significant, proportion of group II patients (65%) as compared with group I (30%). The incidence of intimal tearing or dissection was similar in the two groups of patients (40 vs. 34.7%). The overall final success rate of the complicated angioplasty series was 48% (6/33). However, the success rate was lower (10%) in group I than in group II patients (10 vs. 65%; P less than 0.005), and the frequency of emergency coronary artery bypass grafting was lower in group II patients (13 vs. 60%; P = 0.01), suggesting that thrombolytic therapy with urokinase may be effective in the management of acute coronary occlusion and thromboembolic complications of coronary angioplasty.

Evaluation of noninvasive alternatives to right heart catheterization.

We mechanocardiographically evaluated 50 patients with acute myocardial infarction, invasively monitored by Swan-Ganz catheters, in order to assess if mechanocardiography could provide reliable hemodynamic informations. The last 25 subjects were also studied by pulsed Doppler echocardiography. Our results confirm the high precision of apexcardiography in assessing mean pulmonary capillary wedge pressure (r = 0.91) while Doppler echocardiography proved itself better than mechanocardiography in assessing cardiac output (r = 0.82 vs r = 0.78). Moreover, Doppler echocardiography allowed a good estimation of mean pulmonary artery pressure (r = 0.81) which cannot be assessed by other noninvasive methods. However, we could not find any clinically useful relationship between Doppler mitralic flow characteristics and mean pulmonary capillary wedge pressure. Therefore noninvasive methods could represent a valid alternative to right heart catheterization provided that an integrated Doppler echocardiographic and mechanocardiographic approach is used.