Dipole oscillations of a Bose-Einstein condensate in the presence of defects and disorder

We consider dipole oscillations of a trapped dilute Bose-Einstein condensate in the presence of a scattering potential consisting either in a localized defect or in an extended disordered potential. In both cases the breaking of superfluidity and the damping of the oscillations are shown to be related to the appearance of a nonlinear dissipative flow. At supersonic velocities the flow becomes asymptotically dissipationless.

Upper limit on the diffuse flux of ultrahigh energy tau neutrinos from the Pierre Auger Observatory

The surface detector array of the Pierre Auger Observatory is sensitive to Earth-skimming tau neutrinos that interact in Earth's crust. Tau leptons from nu(tau) charged-current interactions can emerge and decay in the atmosphere to produce a nearly horizontal shower with a significant electromagnetic component. The data collected between 1 January 2004 and 31 August 2007 are used to place an upper limit on the diffuse flux of nu(tau) at EeV energies. Assuming an E(nu)(-2) differential energy spectrum the limit set at 90% C.L. is E(nu)(2)dN(nu)(tau)/dE(nu)<1.3 x 10(-7) GeV cm(-2) s(-1) sr(-1) in the energy range 2 x 10(17) eV< E(nu)< 2 x 10(19) eV.

Family medicine training by distance education

A postgraduate programme is developed to provide Family Medicine training to practising General Practitioners. The programme provides physicians with didactic material by distance education while enhancing clinical competence through face-to-face sessions in ambulatory clinics. Assessment of participating physicians is based on the responses to distance education assignments, case presentations during clinical sessions, clinical examinations at the end of year 2 and the defense of a research project in year 3. Initial programme evaluations demonstrate that the distance education format is successfully incorporated in the discipline of Family Medicine postgraduate training.

Superfluidity versus Anderson localization in a dilute Bose gas

We consider the motion of a quasi-one-dimensional beam of Bose-Einstein condensed particles in a disordered region of finite extent. Interaction effects lead to the appearance of two distinct regions of stationary flow. One is subsonic and corresponds to superfluid motion. The other one is supersonic and dissipative and shows Anderson localization. We compute analytically the interaction-dependent localization length. We also explain the disappearance of the supersonic stationary flow for large disordered samples.

Percussion pacing in a three-year-old girl with complete heart block during cardiac catheterization

Complete heart block frequently requires emergency pacing to restore systemic perfusion. We report the case of a 3-yr-old girl undergoing interventional atrial septal defect closure who suffered from transient complete heart block with circulatory arrest. Transthoracic mechanical pacing for more than 3 min provided temporary support, sustaining an adequate cardiac output until sinus rhythm resumed.

Implantation of an "extracardiac" internal cardioverter defibrillator in a 6-month-old infant

In infants and small children, ICD implantation is a challenge due to technical limitations and a significant number of complications. This report describes ICD implantation in a 6-month-old infant (body weight 5.5 kg). A completely extracardiac defibrillation system was implanted using a transvenous lead subcutaneously in the back below the left scapula as the defibrillation electrode and an active-can device in the right upper abdomen. Defibrillation threshold of implantation was < or =10 J. During the follow-up of 3 months, 8 adequate ICD discharges were noted. The technique described seems feasible to facilitate ICD implantation in small infants.

Fatal complete atrioventricular block as a complication of bacterial sepsis in a premature newborn

We report on a premature infant with a body weight < 900 g who developed complete heart block as a complication of Enterobacter bacteremia. The infant could be successfully paced using a transcutaneous pacemaker for a limited time. Histopathological examination of the heart did not reveal any abnormalities of the specialized conduction system.

Biocompatibility screening in cardiovascular implants

BACKGROUND

Interest in information on biocompatibility of implants is increasing. The purpose of this paper is to discuss methods and results of pathological biocompatibility screening of explanted cardiovascular implants.

METHODS

Use of standard histology after embedding in paraffin is limited since metallic implants have to be removed during workup with disruption of the specimen. Alternatively, tissue blocks containing an implant can be embedded in methylmethacrylate or hydroxyethylmethacrylate and processed by sectioning with a diamond cutter and grinding, thus leaving the implant in situ and saving the tissue/implant interface for detection of local inflammatory reactions. Another important aspect of evaluation is the progress of thrombus organisation after initial fibrin clotting on the metal surface or in the inner part of occlusion devices. New methacrylate resins and embedding techniques allow for specific immunohistochemical staining of the specimen thus enabling characterisation of tissues surrounding the implant. Information on endothelialisation of the vascular surface of the implant can be obtained by means of immunohistochemistry or by scanning electron microscopy.

RESULTS

Illustrating the use of these technologies, we demonstrate findings in tissue specimens from animal studies with different types of devices (i.e. stents, occlusion devices). We present corresponding findings in human specimens with implants that were removed during corrective surgery for congenital heart defects. Early endothelialisation of the vascular surface was seen after implantation in all types of devices. Cells within occlusion devices could be characterised histologically and immunohistochemically as fibromuscular cells as seen in intimal hyperplasia after stent implantation. Inflammatory implant-host reactions ranged from mild to moderate (medical grade stainless steel, nitinol) to severe (polytetrafluoroethylene [PTFE]).

CONCLUSIONS

With an optimal work-up of cardiovascular implants, ingrowth and endothelialisation as well as inflammatory reactions in the surrounding tissue can be assessed. This information allows evaluation of individual tissue reactions to the implant and may serve as valuable basis for optimisation of biocompatibility by implant modification.

Incidence and time course of intimal plaque formation in the right coronary artery after radiofrequency current application detected by intracoronary ultrasound

BACKGROUND

Despite the current clinical use of radiofrequency (RF) catheter ablation in infants and children, the late effects of RF current application at immature myocardium remain unclear. The purpose of this study was to investigate incidence and time course of coronary lesions after RF current application at developing myocardium in an animal model.

RESULTS

In 10 pigs, 6 weeks of age (13+/-2 kg), RF current (500 kHz) was delivered by temperature guidance (75 degrees C) using a steerable electrode catheter (4 mm tip electrode) over 30-second periods. RF lesions were created at the lateral right atrial wall at the tricuspid valve annulus and the lateral left atrial and ventricular wall at the mitral valve annulus. Subsequent coronary angiography and intracoronary ultrasound (ICUS) of the right coronary artery (RCA) and the left circumflex artery (CX) were performed 3, 6, 9 and 12 months after RF current application. Quantitative coronary angiography did not exhibit any significant stenosis of the vessels during the study period. Intimal lesions of the RCA were documented for the first time at the 6-month study in 3 animals by ICUS (mean plaque area 2.2+/-0.2 mm(2), mean area stenosis 30.4+/-4.0%). There was no significant change in lesion length, area stenosis and plaque area at the 9- and 12-month studies. All 3 coronary artery lesions were confirmed in close proximity to myocardial RF lesions by histological examination 12 months after RF delivery. No intimal plaque formation of the CX was observed.

CONCLUSIONS

Affection of the RCA as a late sequel after RF current application at the lateral right atrial wall occurred in 3 out of 8 long-term surviving pigs. Three to six months seem to be the time frame for the development of intimal lesions after RF delivery. In this experimental setting, angiography failed to detect these intimal changes. The potential risk of coronary affection may be important for catheter ablation procedures at the right atrial myocardium in infants and small children.

Phase II trial of intralesional therapy with interleukin-2 in soft-tissue melanoma metastases

The objective of the present study was to validate the use of intralesional injection of interleukin-2 (IL-2) in patients with skin and soft-tissue melanoma metastases. A total of 24 patients with AJCC stage III or IV melanoma and single or multiple skin and soft-tissue metastases were included. Interleukin-2 injections were administered intralesionally into the total number of cutaneous and soft-tissue metastases accessible from the skin, 2-3 times weekly, over 1-57 weeks. Single doses varied from 0.6 to 6 x 10(6) IU, depending on lesion size. The clinical response was monitored by sonography and confirmed by histopathology; response evaluation was confined to the intralesionally treated tumours. Complete response (CR) of the treated metastases was achieved in 15 patients (62.5%), the longest remission lasting 38 months to date. In five patients, partial response (PR) was achieved (21%) and in another three patients, progressive disease was observed (one patient not assessable). A total of 245 metastases were treated with CR in 209 (85%), and PR in 21 (6%). The therapy was generally well tolerated; the observed adverse events were mainly of grade 1-2 severity. Immunohistochemical studies showed the tumour cells undergoing apoptosis and revealed a mixed character of the inflammatory infiltrate. The unusual high CR rate in metastatic melanoma of 62.5% and the limited toxicity suggest that treatment of skin and soft-tissue melanoma metastases with intralesional injection of IL-2 may be a safe and effective alternative to conventional therapies. The optimal dosage and duration of this therapy still remain to be defined in larger prospective multicentre trials.

[Arrhythmogenic right ventricular dysplasia/cardiomyopathy - diagnosis in childhood]

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is a rare, but important cause for sudden death in adolescents and young adults. Part of the patients affected show the pattern of autosomal-dominant inheritance. Two pediatric patients with ARVD/C are presented who may reflect the spectrum of clinical presentation of ARVD/C in childhood resulting in difficulties or even delay to establish the correct diagnosis. One patient with a sporadic form of ARVD/C presented with a syncope and spontaneous as well as inducible ventricular tachycardia. On the ECG, an epsilon wave could be identified. An automatic cardioverter defibrillator was implanted. The second patient had a familiar form of ARVD/C with no symptoms. There was a history of frequent sudden deaths in this family. Biopsies of the right ventricular myocardium showed fibrosis with deposition of fatty tissue. There was clear evidence of ARVD/C in the necropsy of the patient's aunt. Therapy with propanolol was started in this patient.

Ventricular tachycardia in nonpostoperative pediatric patients: role of radiofrequency catheter ablation

Experience concerning radiofrequency catheter ablation (RFCA) of ventricular tachycardia (VT) in pediatric patients is limited. In adults, success rates vary widely based on the etiology of the VT. Highest success rates have been achieved in patients without structural heart disease. Between March 1998 and December 1999, five young patients (age, 5 months to 15 years; body weight, 5.5-61.6 kg) underwent RFCA for VT at our institution [structurally normal heart (n = 4), preoperative tetralogy of Fallot (n = 1)]. Monomorphic VT was present in four children, and an infant with MIDAS syndrome had polymorphic VT. Clinical presentation varied: palpitations, n = 2, congestive heart failure, n = 3. All patients had been proven to be unresponsive to one to six (median, three) antiarrhythmic drugs. In all five patients, VT could be successfully eliminated by RFCA after a total of nine (range, 1-4) procedures. Activation mapping and pace mapping were used to identify the anatomical substrate, which was located in the right ventricle/right ventricular outflow tract in all four patients with monomorphic VT and in the left ventricular septum/left ventricular free wall in the infant with polymorphic VT. There were no significant complications in any patient. During follow-up (20-42 months), all patients are in normal sinus rhythm. Left ventricular function recovered in all three patients who had initially presented with congestive heart failure. RFCA can be effective, safe, and life saving in children with medically resistant VT who have not been operated on for congenital heart disease, even when the VT is polymorphic. Although the number of patients is small, RFCA may be the treatment of choice for symptomatic VT in pediatric patients.

Idiopathic monomorphic ventricular tachycardia originating from the left aortic sinus cusp in children: endocardial mapping and radiofrequency catheter ablation

BACKGROUND

Idiopathic repetitive monomorphic ventricular tachycardia with an inferior axis and left bundle branch block pattern typically originates from the superior right ventricular outflow tract. When indicated, radiofrequency catheter ablation is usually safe and effective. However, a left ventricular origin has been described recently in adult patients in whom ablation attempts in the right ventricular outflow tract were unsuccessful. Experience in pediatric patients is limited.

PATIENTS AND METHODS

Since 1998, 13 young patients suffering from symptomatic ventricular tachycardia episodes with an inferior axis and left bundle branch block pattern underwent an electrophysiological study and radiofrequency catheter ablation. In 2 patients, age 13 and 15 years, no endocardial local electrograms preceding the surface ECG QRS complex could be recorded within the right ventricular outflow tract during ventricular ectopy. Detailed mapping within the left ventricular outflow tract and in the aortic root revealed local electrograms 25 and 53 ms earlier than the QRS complex and a 11/12 and 12/12 lead match during pacing inferior and anterior to the ostium of the left main coronary artery in the left aortic sinus cusp. Earliest activation was recorded 10 and 12 mm away from the coronary artery ostium identified angiographically. In each of the patients, one single radiofrequency current application (60 degrees C, 30 W, duration 30 and 60 s, respectively) resulted in complete cessation of ventricular ectopy. Subsequent selective injection into the left coronary artery did not reveal any abnormalities. During follow-up (2 and 34 months) off any antiarrhythmic drugs, both of the patients are in continuous normal sinus rhythm.

CONCLUSION

In young patients with symptomatic idiopathic ventricular tachycardia originating from the left aortic sinus cusp, radiofrequency catheter ablation was safe and effective.

[Systemic lupus erythematosus-associated endocarditis in a 7-years-old girl]

Systemic Lupus erythematosus (SLE) is a chronic inflammatory disease, caused by a fault of the immune regulation. The etiology of the SLE is still unknown, a possible virus infection is discussed. Libman Sacks endokarditis is the most important cardiac manifestation of this illness. Diagnosis, therapy and clinical course of a 7 years old so far healthy girl, which suffered from an acute Libman-Sacks-Endocarditis, are presented.

Quantitative studies on the peroxidation of human low-density lipoprotein initiated by superoxide and by charged and neutral alkylperoxyl radicals

Rates of peroxidation of human LDL and rates of consumption of the LDL's alpha-tocopherol (TocH) have been measured at 37 degrees C. Peroxidation was initiated by radicals generated in the aerated aqueous phase at known rates by thermal decomposition of appropriate precursors: superoxide (O2(*-)/HOO(*)) from a hyponitrite and alkylperoxyls (ROO(*), two positively charged, one negatively charged and one neutral) from azo compounds. The efficiencies of escape from the solvent cage of the geminate pair of neutral carbon-centered radicals was found to be 0.1, but it was 0.5 for the three charged radicals, a result attributed to radical/radical Coulombic repulsion within the cage. All four alkylperoxyls initiated and terminated tocopherol-mediated peroxidation (TMP) with about equal efficiency and essentially all of these radicals that were generated were consumed in these two reactions. TMP is a radical chain process, and when initiated by the alkylperoxyls, the rate of LDL peroxidation was faster in the early stages while TocH was present than later, after all of this "antioxidant" had been consumed. In contrast, only about 3-4% of the generated superoxide radicals reacted in any measurable fashion with TocH-containing LDL at pH's from 7.6 to 6.5 and peroxidation was much slower than with a similar rate of generation of alkylperoxyls. After all the TocH had been consumed, LDL peroxidation was negligible at pH 7.6 and 7.4, but at pH 6.8 and 6.5, the peroxidation rates showed a large increase over the rates while the TocH had been present. That is, endogenous TocH behaves as an antioxidant in LDL subjected to attack by the physiologically relevant superoxide radical, whereas TocH behaves as a prooxidant in LDL subjected to attack by the probably far less physiologically important alkylperoxyls. Rates of LDL peroxidation initiated by superoxide increased as the pH was decreased, and the results are consistent with the initiation of peroxidation of fresh LDL occurring via H-atom abstraction from TocH by HOO(*) to form the Toc(*) radical and termination by reaction of O2(*-) with Toc(*), a process that occurs partly by addition leading to TocH consumption and partly by electron plus proton transfer leading to the regeneration of TocH.

Influence of walking speed on lower limb muscle activity and energy consumption during treadmill walking of hemiparetic patients

OBJECTIVE

To identify the relationship between treadmill speed and energy consumption and lower limb muscle activity in ambulatory hemiparetic patients.

DESIGN

Experimental cohort.

SETTING

Inpatient rehabilitation clinic.

PARTICIPANTS

Twenty-four ambulatory hemiparetic subjects.

INTERVENTION

Subjects walked harness-secured on the treadmill with no body-weight support at self-reported (V SAS), slow (V SAS - 25%), and fast (V SAS + 25%) speed.

MAIN OUTCOME MEASURES

Assessment of basic, limb-dependent cycle parameters, lower limb muscle activity, and energy consumption.

RESULTS

Cadence (r = .75), stride length (r = .78), relative double-support duration (r = .31), mean muscle activity of the paretic tibialis anterior (r = .12), gastrocnemius (r = .37), vastus lateralis (r =.19), rectus femoris (r = .31), and biceps femoris (r = .45) muscles, as well as heart rate (r = .54), correlated positively with treadmill speed. Mean maximum heart rate was 131 beats/min. Energy (r = -.67) and cardiac cost (r = -.55) correlated negatively with gait speed (ie, patients walked more efficiently at faster velocities). The qualitative muscle activation pattern analysis revealed earlier (more normal) onset of activation of gastrocnemius, vastus lateralis, biceps femoris, and gluteus medius.

CONCLUSIONS

Patients should try to walk fast on the treadmill, thereby facilitating relevant weight-bearing muscles and improving gait efficiency.

Detection of melanoma cells in sentinel lymph nodes, bone marrow and peripheral blood by a reverse transcription-polymerase chain reaction assay in patients with primary cutaneous melanoma: association with Breslow's tumour thickness

BACKGROUND

Tyrosinase reverse transcription-polymerase chain reaction (RT-PCR) has been shown to be highly sensitive in detecting tumour cells in melanoma patients.

OBJECTIVE

To assess whether the detection of minimal residual disease by RT-PCR is improved by concomitant analysis of sentinel lymph nodes (SLNs), bone marrow (BM) and peripheral blood (PB) in patients with primary melanoma.

METHODS

Thirty-five SLNs, 41 BM samples and 26 PB specimens from 26 patients with primary cutaneous melanoma (tumour thickness > or = 0.75 mm) were examined by nested RT-PCR for tyrosinase and Melan-A. SLNs and BM samples were also analysed by histopathology. RT-PCR findings were related to tumour thickness of the primary melanoma.

RESULTS

Overall, melanoma cells were detected by RT-PCR in 13 of 26 patients (50%). Seven patients had positive RT-PCR results in their SLNs (27%), including all patients (n = 4) with histologically positive SLNs, two patients had positive findings in their BM exclusively detected by RT-PCR (8%) and six patients in PB (23%). The presence of tumour cells detected by RT-PCR in SLNs was not related to the presence of melanoma cells in BM and/or PB. The incidence of RT-PCR-positive SLNs was significantly associated with greater tumour thickness (P = 0.004). Both patients with positive RT-PCR findings in their BM had a large tumour thickness (> or = 2 mm). No association between positive RT-PCR findings in PB and greater tumour thickness was observed.

CONCLUSIONS

RT-PCR-positive SLNs were strongly associated with greater tumour thickness, underlining the prognostic significance of SLN positivity. Similar to certain epithelial malignancies, molecular investigation of the BM might provide complementary prognostic information in the early stages of melanoma. In contrast, no association between positive RT-PCR results in PB and increasing tumour thickness was found, implying that RT-PCR findings in PB are of doubtful clinical relevance in primary melanoma.

Primary repair of tetralogy of fallot in infancy--the effect on growth of the pulmonary arteries and the risk for late reinterventions

We sought to analyse the long-term follow-up after primary repair of tetralogy of Fallot in infancy in the first year of life, paying particular attention to growth of the pulmonary arteries and the need for reintervention. We performed a combined retro- and prospective echocardiographic study, including measurements of the pulmonary valve and right and left pulmonary arteries, indexed to the square root of body surface area, in 62 patients prior to primary repair, 18 to 24 months after this event, and at the most recent follow-up, with a mean of 80.4+/-24 months. Of these, 38 patients, with an age at operation of 5.0+/-3.4 months, had presented preoperatively with hypoxic spells or increasing cyanosis. The remaining 24 patients had been asymptomatic, with adequate flow of blood to the lungs. Their age at elective operation was 7.4+/-3.0 months. A transannular patch was needed in 37 patients (63%). There were 3 early postoperative deaths (4.8%). Cross-sectional echocardiography revealed a significantly smaller diameter for the pulmonary valve in patients who had been symptomatic preoperatively compared to the asymptomatic patients (1.09 versus 1.3 cm/BSA0.5; p = 0.019). The diameters of the right and left pulmonary arteries did not differ significantly between the groups. Examination of echocardiographic data obtained 18 to 24 months postoperatively in 43 patients revealed a significant increase in the diameter of the pulmonary arteries; 0.83+/-0.17 cm/BSA0.5 versus 1.1+/-0.26 cm/BSA0.5 for the diameter of the right pulmonary artery, 0.85+/-0.2 cm/BSA0.5 versus 1.0+/-0.25 cm/BSA0.5 for the left pulmonary artery. On comparison between individuals, 18.6% and 25.6% of the patients, respectively, did not show any change in the diameters of their right and left pulmonary arteries, whereas the increase in diameter reached or exceeded the measurements in normal controls in 55.8% and 46.5% of the patients, respectively. On recent follow-up, with a range from 56 to 147 months, no further increase in the indexed diameters of the pulmonaries could be documented in 21 of 33 patients. Of these, 9.1% and 18.2%, respectively, presented with small right and left pulmonary arteries compared with measurements obtained in normal controls. Moderate pulmonary incompetence was found on colour flow mapping in one-third. Of 56 longterm survivors, 8 (14%) had required reinterventions, which were surgical in 6 and achieved by transcatheter techniques in the other 2 patients. Thus, primary correction of tetralogy of Fallot in infancy, with restoration of normal pressures and flows, resulted in sustained increase in the diameters of the right and left pulmonary arteries. It allowed for early normal development of the proximal pulmonary arterial system in most patients regardless of their age and symptomatic status at operation. Patients with persistent subnormal diameter of the pulmonary arteries did not present with significantly elevated right ventricular pressure. Early one-stage repair of tetralogy of Fallot in infancy was associated with a low rate of reinterventions.

Experimental preseeding of the STARFlex atrial septal occluder device with autologous cells

Devices used in interventional cardiology are permanent implants. However, most of the devices fulfill only a temporary function. For example, atrial septal defect (ASD) occluders serve as mechanical shields until complete in- and overgrowth of the occluding device by endogenous tissue from the defect edges has occurred. Thereafter, the foreign body material of the devices is no longer needed and bears potential long-term adverse effects. The concept of "biodegradable" occluder devices that act as transient mechanical shields to close the defects and as scaffolds for overgrowth with autologous tissue is, therefore, tempting. Since rapid and complete ingrowth as well as coverage by firm tissue is a prerequisite for any such "biological" occluder devices, the feasibility and short-term in vivo response to STARFlex devices preceeded with autologous cells was studied in an experimental sheep model. The experiments demonstrated that autologous cell preceeding of cardiovascular implants is technically feasible. Cells survived the mechanical stress of device implantation. A precoating of conventional STARFlex occluders led to an increased cellular density after cell seeding of the device, an increased resistance of the precultured cytolayer against mechanical stress, and a significantly higher poststress viability of "implanted" cells. Experimental closure of ASD using autologous-cell preseeded STARFlex devices was uncomplicated. In the sheep model this led to rapid, complete, and firm ingrowth of the device into the adjacent atrial tissue. A thicker layer of young fibrous granulation tissue in organization was found on the preceeded devices compared with the unseeded control group after 4 weeks in vivo. Currently, an increased thrombogenicity limits in vivo application.

Intralesional rituximab for cutaneous B-cell lymphoma

Rituximab, a chimeric anti-CD20 monoclonal antibody, has been approved for systemic treatment of relapsed or refractory CD20-positive B-cell non-Hodgkin's lymphoma. As cutaneous B-cell lymphoma (CBCL) also expresses the CD20 molecule, three patients with histologically and immunohistochemically confirmed CBCL without systemic involvement were treated with low-dose intralesional rituximab in a pilot study. Single doses applied ranged from 10 to 30 mg per lesion, according to lesion extent, with a cumulative dose of up to 350 mg. Injections were given two or three times weekly for 3-5 weeks, with a second cycle after 6 weeks in one patient with incomplete remission. Complete and lasting remission was achieved in each patient; this has persisted for up to more than 1 year. The observed adverse events were of grade 1 severity. Results suggest that intralesional rituximab may be a safe and effective new therapy modality for CBCL.

Atrial reentrant tachycardia after surgery for congenital heart disease: endocardial mapping and radiofrequency catheter ablation using a novel, noncontact mapping system

BACKGROUND

The purpose of the present study was to determine the role of a novel, noncontact mapping system for assessing a variety of atrial reentrant tachycardias (ART) in patients after the surgical correction of congenital heart disease.

METHODS AND RESULTS

In 14 patients, an electrophysiological study using the Ensite 3000 system was performed to assess ARTs resistant to medical treatment. Sixteen different forms of ART were inducible in the 14 patients studied. The reentrant circuit of all ARTs could be characterized and localized with respect to anatomic landmarks such as atriotomy scars, intraatrial patches/baffles, and cardiac structures. In 15 of the 16 ARTs (in 13 of the 14 patients), a target area of the reentrant circuit for radiofrequency current application (ie, an area of conduction between 2 anatomical obstacles such as surgical barriers and cardiac structures of electrical isolation) could be localized within the systemic venous atrium. Nine patients exhibited macroreentry, and 4 showed microreentry. In 12 patients, ART could be terminated by creating linear radiofrequency current lesions (75 degrees C, 180 to 390 s). Completeness of linear lesions after radiofrequency current delivery was proven by analyzing color-coded isopotential maps of atrial activation while applying atrial pacing techniques. The mean duration of the procedures was 286 minutes (range, 130 to 435 minutes); fluoroscopy time ranged from 7 to 33.8 minutes (mean, 17.4 minutes).

CONCLUSIONS

In patients with ART after the surgical correction of congenital heart disease, the use of the noncontact mapping system allows for characterization of the tachycardia and guidance for effective radiofrequency current delivery.

Abbreviated combined anatomical/electrophysiological approach for catheter ablation of atrioventricular nodal reentrant tachycardia in children

Atrioventricular nodal reentrant tachycardia was proven during electrophysiologic study in 41 children, aged from 3.7 to 16 years, who were referred for catheter ablation of symptomatic supraventricular tachycardia. Using an abbreviated combined anatomical and electrogram-guided approach for selective ablation of the slow pathway, a steerable ablation catheter was placed at the inferior region of the vestibule of the tricuspid valve close to the orifice of the coronary sinus, with the intention of recording a multicomponent local atrial electrogramm during sinus rhythm. If application of radiofrequency current of 500 kHz at 70 degrees C at this site did not result in a slowly accelerated junctional rhythm, at a rate of less than 120 beats per minute, the catheter was stepwise advanced up to a position midway towards the apex of the triangle of Koch for additional applications of energy. Ablation was achieved in 35 of the patients. In 6 patients, the slow pathway was modulated such that the tachycardia could no longer be induced. The number of applications of energy ranged from 1 to 19, with a median of 6 applications. The mean period of fluoroscopy was reduced to 15.6 (4.3 to 39.8) minutes, while the overall duration of the catheterization procedures ranged from 88 to 280 (mean 173.2) minutes. In none of the patients did we observe permanent high grade atrioventricular block. During follow-up over a mean of 4.1 years, two patients had recurrence of tachycardia, corresponding to a 95% rate of success in the midterm. We conclude that selective radiofrequency ablation of the slow pathway using the abbreviated anatomical and electrophysiological approach is a safe and curative therapeutic approach in children with atrioventricular nodal reentrant tachycardia. Periods required for fluoroscopy can be significantly reduced, and mid-term results are excellent.

Transcatheter closure of various types of defects within the oval fossa using the double umbrella device (CardioSEAL)--feasibility and echocardiographic follow-up

Data on long-term follow-up for closure of so-called secundum type" atrial septal defects within the oval fossa using recently developed devices are limited, and results focused on presence of residual shunting. The purpose of our study was to report the experience from a single center establishing the effectiveness of transcatheter closure in patients with various types of defect other than those located centrally within the oval fossa. A total of 72 patients was included in this study. On transesophageal echocardiography, the size of the defects varied from 6 to 18 mm, with estimation of the stretched diameter from 11 to 21 mm. The ratio of stretched diameter to the extent of the residual septum ranged from 0.28 to 0.54. Mean follow-up was 30.5+7.4 months, with a range from 13 to 42 months. The rate of closure using devices with diameters from 28 to 40 mm increased from 80% immediately after implantation to 93% in the 57 patients examined 24 months after implantation. For further analysis, we compared the 44 patients with a solitary, centrally located, defect to 28 having morphological variations, including superiorly located defects with deficient superior and aortic rims, multifenestrated and aneurysmal defects, or isolated additional defects. There was no incidence of formation of thrombus, sustained atrial arrhythmia, or infective endocarditis. Residual shunting was not influenced by location or morphology of the defects, but increased with size, stretched diameter, and the ratio of pulmonary to systemic flows. Serial transthoracic echocardiographic findings revealed malposition of one right-sided superior arm of the device in 8 patients, while protrusion of one left-sided arm onto the right atrial aspect was observed in 3 patients. Fluoroscopy showed fatigue fracture of a single arm in 7 patients (9.7%) within the first 6 months after implantation. These results demonstrate that transcatheter closure with the non self-centering double umbrella device was effective and safe on medium-term follow-up, and could be extended to defects within the oval fossa having various morphologies. Residual shunting resolved with time, and was not related to either morphology or the position of the device.

Coronary artery stenosis after radiofrequency catheter ablation of accessory atrioventricular pathways in children with Ebstein's malformation

BACKGROUND

Complications concerning the coronary arteries that are directly related to radiofrequency catheter ablation procedures have not been reported in children. Coronary artery lesions, however, have been demonstrated after the endocardial application of radiofrequency current in young animals.

METHODS AND RESULTS

Two boys with Ebstein's anomaly of the tricuspid valve developed clinically asymptomatic coronary artery stenosis after radiofrequency catheter ablation of right-sided accessory atrioventricular pathways with standard catheter technology.

CONCLUSIONS

The complication of coronary artery stenosis demonstrates a substantial risk after right atrial free wall radiofrequency current application in children. The risk of late coronary alterations should be considered when the use of catheter ablation procedures to young patients is proposed.

A novel procedure for generating both nitric oxide and superoxide in situ from chemical sources at any chosen mole ratio. First application: tyrosine oxidation and a comparison with preformed peroxynitrite

The first method for generating (*)NO and O(2)(*)(-) at any known, constant ratio has been developed. Spermine NONOate and di(4-carboxybenzyl)hyponitrite decay with first-order kinetics and exactly equal rate constants (half-lives of 80 min) at 37 degrees C and pH 7.5 to give 200 and 40 mol % (*)NO and O(2)(*)(-), respectively. Tyrosine oxidation to dityrosine and 3-nitrotyrosine (the major and minor products under the conditions used in these experiments) has been studied (mainly in the presence of CO(2)) using various different ratios of the rates of formation of (*)NO and O(2)(*)(-). The (*)NO/O(2)(*)(-) = 1.0 product profiles are very similar to those of the products derived from equal amounts of (*)NO and O(2)(*)(-) generated at a (*)NO/O(2)(*)(-) ratio of 1.0 from SIN-1 but are very different from those derived from preformed peroxynitrite. All the experimental results can be explained in terms of free radical chemistry. The product profiles at all the (*)NO/O(2)(*)(-) ratios could be satisfactorily simulated provided an important group of reactions which lead to the consumption of dityrosine was included.

Synthesis of stereodefined polysubstituted olefins. 1. Sequential intermolecular reactions involving selective, stepwise insertion of Pd(0) into allylic and vinylic halide bonds. The stereoselective synthesis of disubstituted olefins

Palladium-catalyzed allylic substitution and cross-coupling reactions have been combined into a sequential procedure to provide a range of disubstituted olefin products starting from two-, three-, and four-carbon common olefin templates. Diverse application of this template strategy is demonstrated in a variety of model studies and in a parallel synthesis (combinatorial) approach to prepare an allylic amine molecular library. An approach toward the preparation of astaxanthin beta-D-diglucoside, an interesting antioxidant whose total synthesis has yet to be reported, using the olefin-template approach is also discussed.

Effect of a prolonged superoxide flux on transferrin and ferritin

The involvement of "free" iron in damage caused by oxidative stress is well recognized. Superoxide generated in a short burst and at a relatively high flux by the xanthine/xanthine oxidase couple is known to release iron from ferritin in the presence of phenanthroline derivatives as iron chelators. However, superoxide generation via xanthine oxidase is accompanied by the simultaneous direct generation of hydrogen peroxide and, in the presence of ferritin, there is also a superoxide-independent release of iron. In this study it was found that the iron chelator employed attenuates superoxide formation from the xanthine/xanthine oxidase couple. The reaction of ferritin and transferrin with a clean chemical source of superoxide, di(4-carboxybenzyl)hyponitrite (SOTS-1) was therefore investigated. The efficiency of superoxide-induced iron release from ferritin increases dramatically as the superoxide flux is decreased, reaching as high as 0.5 Fe per O2*-. Treatment of ferritin for 16 h with SOTS-1 yielded as many as 130 Fe atoms/ferritin molecule, which greatly exceeds the amount of possible "contaminating" iron absorbed on the protein shell.

How should xanthine oxidase-generated superoxide yields be measured?

The rate of formation of superoxide measured by its reduction of tetranitromethane (TNM) and by its reduction of ferric cytochrome c (Fe(III) cc) are in excellent agreement when the superoxide is generated from a simple chemical precursor. In contrast, the rate of formation of superoxide generated in the reaction of xanthine oxidase with acetaldehyde is much higher (up to a factor of 6) when measured with TNM and compared with Fe(III) cc. It is shown that Fe(III) cc measures superoxide that has diffused from the enzyme, and that TNM probably scavenges all the dioxygen that is reduced by one electron by the enzyme. The TNM traps enzyme-bound superoxide in competition with the second-electron transfer and proton transfer, which normally yield hydrogen peroxide. The proton transfer is probably rate determining, k(p) </= 3.8x10(3)s(-1).

Management of severe traumatic brain injury by decompressive craniectomy

OBJECTIVE

The beneficial effect of decompressive craniectomy in the treatment of head trauma patients is controversial. The aim of our study was to assess the value of unilateral decompressive craniectomy in patients with severe traumatic brain injury.

METHODS

We retrospectively investigated 49 patients who underwent decompressive craniectomy. Intracranial pressure, cerebral perfusion pressure, therapy intensity level, and cranial computed tomographic scan features (midline shift, visibility of ventricles, gyral pattern, and mesencephalic cisterns) were evaluated before and after craniectomy. The gain of intracranial space was calculated from cranial computed tomographic scans. Patient outcome was graded using the Glasgow Outcome Scale.

RESULTS

Thirty-one patients (63.3%) underwent rapid surgical decompression within 4.5 +/- 3.8 hours after trauma; in 18 patients (36.7%), delayed surgical decompression was performed 56.2 +/- 57.0 hours after injury. Patients younger than 50 years or patients who underwent rapid surgical decompression had a significantly better outcome than older patients or patients who underwent delayed surgical decompression. Craniectomy significantly decreased midline shift and improved visibility of the mesencephalic cisterns. The state of the mesencephalic cisterns correlated with the distance of the lower border of the craniectomy to the temporal cranial base. Alterations in intracranial pressure, cerebral perfusion pressure, and therapy intensity level were not significant. The overall mortality of the patients corresponded to the reports of the Traumatic Coma Data Bank (1991).

CONCLUSION

Although there was a significant decrease in midline shift after craniectomy, this did not translate into decompressive craniectomy demonstrating a beneficial effect on patient outcome.