PL03.3.A Development and characterization of CD317-specific CAR T cells as an innovative immunotherapeutic strategy against glioblastoma

BACKGROUND

Due to the limited success of existing therapies for gliomas, innovative therapeutic options are urgently needed. Chimeric antigen receptor (CAR) T cell therapy has been successful in patients with hematological malignancies. However, using this treatment against solid tumors such as glioblastomas is more challenging. Here, we generated CAR T cells targeting the transmembrane protein CD317 (BST-2, HM1.24) which is overexpressed in glioma cells and may therefore serve as a novel target antigen for CAR T cell-based immunotherapy.

MATERIAL AND METHODS

CAR T cells targeting CD317 were generated by lentiviral transduction of human T cells from healthy donors. The anti-glioma activity of CD317-CAR T cells was determined in lysis assays using different glioma target cell lines with varying CD317 expression levels. The efficiency of CD317-CAR T cells to control tumor growth in vivo was evaluated in clinically relevant orthotopic xenograft glioma mouse models.

RESULTS

We created a second-generation CAR construct targeting CD317 and observed strong anti-glioma activity of CD317-CAR T cells in vitro. Glioma cells with a CRISPR/Cas9-mediated CD317 knockout were resistant to CD317-specific CAR T cells, demonstrating their target antigen-specificity. Since CD317 is also expressed by T cells, transduction with a CD317-directed CAR resulted in fratricide of the transduced T cells. Silencing of CD317 in CAR T cells by integrating a specific shRNA into the CAR vector significantly increased the viability, proliferation and cytotoxic function of the CAR T cells. Importantly, intratumoral treatment with CD317-CAR T cells prolonged the survival and cured a significant fraction of glioma-bearing nude mice.

CONCLUSION

We demonstrate strong CD317-specific anti-tumor activity of CD317-CAR T cells against various glioma cell lines in vitro and in xenograft glioma models in vivo. These data lay a scientific basis for the subsequent evaluation of this therapeutic strategy in clinical neuro-oncology.

Lenalidomide added to standard intensive treatment for older patients with AML and high-risk MDS

More effective treatment modalities are urgently needed in patients with acute myeloid leukemia (AML) of older age. We hypothesized that adding lenalidomide to intensive standard chemotherapy might improve their outcome. After establishing a safe lenalidomide, dose elderly patients with AML were randomly assigned in this randomized Phase 2 study (n = 222) to receive standard chemotherapy ("3 + 7") with or without lenalidomide at a dose of 20 mg/day 1-21. In the second cycle, patients received cytarabine 1000 mg/m² twice daily on days 1-6 with or without lenalidomide (20 mg/day 1-21). The CR/CRi rates in the two arms were not different (69 vs. 66%). Event-free survival (EFS) at 36 months was 19% for the standard arm versus 21% for the lenalidomide arm and overall survival (OS) 35% vs. 30%, respectively. The frequencies and grade of adverse events were not significantly different between the treatment arms. Cardiovascular toxicities were rare and equally distributed between the arms. The results of the present study show that the addition of lenalidomide to standard remission induction chemotherapy does not improve the therapeutic outcome of older AML patients. This trial is registered as number NTR2294 in The NederlandsTrial Register (www.trialregister.nl).

Perceptions and Attitudes toward Data Sharing among Dental Researchers

Introduction:

Increasing attention is being given to the roles of data management and data sharing in the advancement of research. This study was undertaken to explore opinions and past experiences of established dental researchers as related to data sharing and data management.

Methods:

Researchers were recruited from the International Association for Dental Research scientific groups to complete a survey consisting of Likert-type, multiple-choice, and open-ended questions.

Results:

All 42 respondents indicated that data sharing should be promoted and facilitated, but many indicated reservations or concerns about the proper use of data and the protection of research subjects. Many had used data from data repositories and received requests for data originating from their studies. Opinions varied regarding restrictions such as requirements to share data and the time limits of investigator rights to keep data. Respondents also varied in their methods of data management and storage, with younger respondents and those with higher direct costs of their research tending to use dedicated experts to manage their data.

Discussion:

The expressed respondent support for research data sharing, with the noted concerns, complements the idea of developing managed data clearinghouses capable of promoting, managing, and overseeing the data-sharing process.

Knowledge Transfer Statement:

Researchers can use the results of this study to evaluate and improve management and sharing of research data. By encouraging and facilitating the data-sharing process, research can advance more efficiently, and research findings can be implemented into practice more rapidly to improve patient care and the overall oral health of populations.

Distinct factors determine the kinetics of disease relapse in adults transplanted for acute myeloid leukaemia

BACKGROUND

Disease recurrence remains the major cause of death in adults with acute myeloid leukaemia (AML) treated using either intensive chemotherapy (IC) or allogenic stem cell transplantation (allo-SCT).

AIMS

The timely delivery of maintenance drug or cellular therapies represent emerging strategies with the potential to reduce relapse after both treatment modalities, but whilst the determinants of overall relapse risk have been extensively characterized the factors determining the timing of disease recurrence have not been characterized.

MATERIALS AND METHODS

We have therefore examined, using a series of sequential landmark analyses, relapse kinetics in a cohort of 2028 patients who received an allo-SCT for AML in CR1 and separately 570 patients treated with IC alone.

RESULTS

In the first 3 months after allo-SCT, the factors associated with an increased risk of relapse included the presence of the FLT3-ITD (P < 0.001), patient age (P = 0.012), time interval from CR1 to transplant (P < 0.001) and donor type (P = 0.03). Relapse from 3 to 6 months was associated with a higher white cell count at diagnosis (P = 0.001), adverse-risk cytogenetics (P < 0.001), presence of FLT3-ITD mutation (P < 0.001) and time interval to achieve first complete remission (P = 0.013). Later relapse was associated with adverse cytogenetics, mutated NPM1, absence of chronic graft-versus-host disease (GVHD) and the use of in vivo T-cell depletion. In patients treated with IC alone, the factors associated with relapse in the first 3 months were adverse-risk cytogenetics (P < 0.001) and FLT3-ITD status (P = 0.001). The factors predicting later relapse were the time interval from diagnosis to CR1 (P = 0.22) and time interval from CR1 to IC (P = 0.012).

DISCUSSION AND CONCLUSION

Taken together, these data provide novel insights into the biology of disease recurrence after both allo-SCT and IC and have the potential to inform the design of novel maintenance strategies in both clinical settings.

[Treatment results of nasopharyngeal carcinoma in adults]

BACKGROUND

Nasopharyngeal carcinoma (NPC) is a rare tumor entity in Germany in contrast to endemic countries in Asia or Africa. This retrospective study investigated patient characteristics and prognostic factors with respect to different NPC treatment strategies.

PATIENTS AND METHODS

A total of 63 NPC patients treated during the period 1990-2009 at the University Hospital Bonn, Germany, were included.

RESULTS

The median age of the patients was 56.4 years, the male:female ratio was 3.2:1, 23.8% were in Union Internationale Contre le Cancer (UICC) stage I/II and 76.2% were in stage III/IV. Most of the carcinomas were WHO type III (57.1%), followed by World Health Organization (WHO) type II (33.3%) and at last WHO type I (9.6%). The 5-year overall survival rate after concomitant chemoradiotherapy (RCT) was 75% and after radiotherapy (RT) 60%. The mortality rate increased by 3.5 times with each increase in T-stage (p ≤ 0.047). The recurrence rate (RR) after RCT was 34% and after RT alone 68% (p ≤ 0.04). Tumor ablation increased the RR significantly (p ≤ 0.047).

CONCLUSION

Combined chemotherapy and RT is an effective treatment of NPC disease and clearly superior to RT alone. Tumor ablation before RCT/RT worsens the prognosis and is now obsolete.

[Analysis of quality of life outcome for nasopharyngeal carcinoma patients after treatment]

BACKGROUND

This retrospective study analysed patient characteristics and quality of live (QoL) for patients with nasopharyngeal carcinoma (NPC) after treatment.

MATERIAL AND METHODS

A cross-sectional investigation was conducted to assess the QoL of 20 NPC patients with cancer-free survival of more than one year, which were treated with radiotherapy (RT) or chemoradiotherapy (RCT) during the period 2001-2009 at the University Hospital Bonn, Germany. The QoL was assessed by the FACT-NP (functional assessment of cancer therapy-nasopharyngeal) questionnaire.

RESULTS

The median age of the patients was 57 ± 13 years and the male/female ratio was 2.33/1.3 (15%) patients were treated with RT and 17 (85%) with RCT. The global QoL was good in our patients. Xerostomia, chewing, decrease of gustatory sense, discontent with sexual life and ear problems were of major concern with the majority of patients and affected the QoL negatively. Pain, lost of working ability, emotional distress, or family problems were no significant factors.

CONCLUSION

The expected reduction of QoL after treatment must be explained in detail to the NPC patient. The integration of the family and partner, an antidepressant therapy or psycho-oncological support can be useful and necessary.

[Bronchogenic cyst: a rare cause of a retroperitoneal mass]

BACKGROUND

Bronchogenic cysts are developmental abnormalities of the primitive foregut which typically occur in the lung. Subdiaphragmatic and, especially, retroperitoneal locations are rare. The histopathological definition consists of the presence of ciliated epithelium together with cartilage or bronchial mucous glands.

CASE PRESENTATION

We report on a 49-year-old patient with the incidental finding of a large cystic mass between the diaphragm and the stomach. Imaging studies suggested an adrenal tumour. Surgical resection and postoperative follow-up were uneventful. Histological examination revealed the surprising diagnosis of a bronchogenic cyst.

CONCLUSION

Bronchogenic cysts must be considered in the differential diagnosis of retroperitoneal cystic lesions. Regardless of being asymptomatic most of the time, surgical resection is recommended to obtain definitive histological diagnosis and avoid future complications.

Comparison of two antacid preparations on intragastric acidity--a two-centre open randomised cross-over placebo-controlled trial

BACKGROUND

Rennie and Riopan Gel are 2 of the most well-known and popular over-the-counter antacids; for heartburn symptoms, pain relief is fast with both preparations. A direct comparison with respect to intragastric acidity has not been done yet. The aim of our study was therefore to compare the effects of both preparations on intragastric acidity of fasting volunteers.

METHODS

The study was conducted as an open, randomised, placebo-controlled, 2-centre cross-over study. On different days, 24 healthy adult volunteers (11 males and 13 females) received equimolar acid-neutralising amounts of either Riopan Gel (800 mg magaldrate) or 2 tablets of Rennie (680 mg calcium carbonate and 80 mg magnesium carbonate) or no drug (control) with a wash-out period of at least 4 days between applications. The intragastric pH was measured for 3 h by intragastric pH-metry. The primary endpoint was the median time lag before intragastric pH >3.0 was reached for 10 consecutive min after drug administration.

RESULTS

For both antacids, the median pH during the first 30 min after drug administration was statistically significantly different from placebo (p < 0.05), but there was a statistically significant increase in pH during the first 5 min for Riopan Gel only.

CONCLUSION

Compared to placebo, both antacids (Rennie and Riopan Gel) have short-lasting effects on intragastric acidity. There is no statistically significant difference between the 2 preparations, except in the first 5 min, indicating a faster onset of action for Riopan Gel. We conclude that the antacid formulation (tablet or liquid) has little influence on intragastric acidity.

[Esophageal intramural pseudodiverticulosis]

We report two cases of esophageal intramural pseudodiverticulosis (EIPD). EIPD is a rare condition characterized by multiple flask-shaped outpouchings in the esophageal wall representing dilated excretory ducts of submucosal glands. Dysphagia is the leading symptom. On endoscopy, minute openings in the esophageal wall, and sometimes a segmental candida esophagitis or a benign stenosis not originating from an erosive reflux esophagitis are found.

Pharmakologische Therapie von Transitstörungen

Der gastrointestinale Transit kann durch eine gesteigerte oder gehemmte Motilität gestört sein. Pharmakologisch können wir die Motilität im Gastrointestinaltrakt aktivieren oder hemmen. Am Beispiel der funktionellen Dyspepsie und der Gastroparese werden die vor allem im oberen Magendarmtrakt wirksamen Prokinetika Metoclopramid und Domperidon, Erythromycin und Tegaserod diskutiert. Bei der medikamentösen Therapie der chronischen Obstipation kommen Fasern, Gleitmittel, osmotische und sekretorische Laxantien zum Einsatz. Die Therapie des Reizdarmsyndroms basiert auf den Leitsymptomen. Steht die Obstipation im Vordergrund werden Fasern, iso-osmotische Laxantien und Tegaserod eingesetzt. Bei Schmerzen als Leitsymptom können Spasmolytika oder Trizyklische Antidepressiva versucht werden. Das Reizdarmsyndrom mit Diarrhö spricht auf Loperamid gut an.

Cryptosporidiosis in a patient on PEG-interferon and ribavirin for recurrent hepatitis C after living donor liver transplantation

We report a case of a 48-year-old male who developed cryptosporidial enterocolitis while on pegylated-interferon alpha-2a and ribavirin for recurrent hepatitis C 2 years after living donor liver transplantation. He recovered after discontinuation of interferon and ribavirin and intermittent lowering of the immunosuppressant. We postulate that the myelodepressant effect of interferon and ribavirin in addition to an established immunosuppressive regimen permitted this opportunistic infection. To the best of our knowledge, this is the first case of cryptosporidiosis in a patient treated with interferon and ribavirin for recurrent hepatitis C after liver transplantation in the literature.

[Water supply for Peking ducks--possible alternatives for bathing]

In order to investigate possible advantages of open water drinkers such as troughs and bells in the intensive husbandry of ducks, we evaluated in this study the effect of open water systems on the behavior and health of peking ducks. In this investigation six fattening trials each with 1152 Cherry Valley Peking ducks were analyzed. The average fattening period was 47 to 49 days. The ducks were kept on straw in six standardized compartments each 32 qm with 192 ducks. 25% of the compartment with perforated grid, with one of the tested water systems. In contrast to pens with nipple-drinkers only, the ducks in pens with open water troughs/showers had the opportunity to exhibit their natural drinking behavior and water associated activities in accordance with the animal welfare requirements. In the free-choice pens the open water systems were significantly preferred, and over a 24-hour period the ducks in watering areas with open water troughs showed higher activity. Limiting the access to the open water systems to eight, four or two hours per day led to an increased use per time unit. Ducks with access to nipple drinkers only showed a significantly higher percentage of plugged up nostrils than animals from pens with open water drinkers. Open water drinkers had also a positive impact on the plumage condition.

Fate of POPs (DDX, HCHs, PCBs) in upper soil layers of pine forests

Organochlorines (HCH isomers, DDX and individual PCBs) were determined in pine needle litter and upper soil layers of three forest test areas in central Germany. The contents accumulating over a number of years or even decades in the organic surface layer are compared with the levels of new inputs from needle fall as well as with the levels of older inputs in the upper mineral soil layer. Differences in behaviour between the soil horizons are discussed, especially concerning the DDX and HCH groups. With approximately comparable Corg values (approx. 21-24%) the pH value in the range of 4.24-2.90 in the O-horizon of the forest soils exerts a large influence. Hence the A-horizon represents--for p,p'-DDT and gamma-HCH in particular--at pH values of 2.90 a pollutant reservoir which should not be underestimated and which could endanger the rhizosphere and the groundwater. According to PCBs, in the more acidic soils with a pH value <4.0 the lipophilic higher polychlorinated biphenyls were found to be more highly enriched in the humus layer.

[Therapy of cardiac arrhythmias. Clinical significance of potassium- and magnesium aspartate in arrhythmias]

Potassium and magnesium deficiencies usually coexist and represent a risk factor for cardiac arrhythmias. Serum levels--in particular of magnesium--are inconclusive for establishing a possible electrolyte deficiency. Basic treatment of arrhythmia should therefore include the administration of potassium and magnesium, since the benefit is great, and the possible side effects is negligible. A placebo-controlled study involving patients with cardiac arrhythmias revealed that appreciably fewer ventricular asystoles occurred after three weeks of treatment with potassium and magnesium aspartate, even when serum levels were within the normal range prior to initiating treatment. Patients older than 50, and those with previous coronary heart disease and/or myocardial infarction derived particular benefit from this form of treatment.

CONCLUSION

These results underscore the key role played by potassium and magnesium in the treatment of cardiac arrhythmias.

Application of different RP-HPLC methods for the determination of the octanol/water partition coefficient of selected tetrachlorobenzyltoluenes

Reversed-phase high-performance liquid chromatography (RP-HPLC) in both, isocratic and gradient elution mode (stationary phase: LiChrospher 100 RP-18; mobile phase: water/methanol or water/acetonitrile) was used for a renewed determination of octanol/water partition coefficients (Kow) of selected tetrachlorobenzyltoluene (TCBT) isomers. Reported Kow values identify this substance class as very hydrophobic but the data are relatively inconsistent. Based on a series of calibration runs with hydrophobic reference substances of different chemical structure at various eluent compositions we tested different approaches for the evaluation of isocratic retention factors (logk) and found substantial differences between the direct calibration procedure at special methanol volume fractions in the mobile phase (0.95-0.80) and the use of retention factors extrapolated to pure water as eluent (logkw). The logKow values obtained for the TCBTs with the latter approach are around 0.5 units higher and closer to literature data. The gradient elution experiments yield slightly better results compared to the isocratic direct calibration procedure, but not as good as the calibration with log kw. In addition, the use of the RP-HPLC retention factors for estimating sorption coefficients (Koc) of TCBT isomers is discussed.

Persistent organic pollutants in agricultural soils of central Germany

Concentrations of persistent organic pollutants (HCHs, DDX, PCBs and HCB) were measured in topsoils from 11 agricultural fields in the lee of large disused industrial plants in the Leipzig-Halle region at varying distances from emitters. The investigations clearly indicate the deposition of anthropogenic pollutant inputs, not only in the past, but also today. The pollution potential was assessed on the basis of current guide values and limits, as well as in relation to values found in agricultural soils elsewhere in Germany, in Europe and in the USA. The reference values were mainly exceeded for DDX and gamma-HCH (lindane). The PCB pattern was determined and the degradation ratios between the parent substances and their metabolites (DDX and HCH isomers) were calculated in order to distinguish between the previous and current pollutant input of pesticides by means of principal component analysis.

High-grade lymphoma mimicking bone crisis in Gaucher's disease

A 33-year-old woman with type 1 Gaucher's disease developed painful swelling of her right tibia. Initial diagnostics suggested a typical bone crisis. However, clinical course and subsequent imaging pointed to malignant disease, which was specified as high-grade lymphoma. Chemotherapy was applied together with enzyme replacement and resulted in complete remission of the lymphoma. We conclude that osseous lesions, although suggestive of common manifestations of Gaucher's disease, should be discriminated very carefully from neoplastic infiltration to maintain curative treatment options.

Development of CD8alpha-positive dendritic cells from a common myeloid progenitor

Dendritic cells (DCs) are critical in both initiating adaptive immune responses and maintaining tolerance to self antigens. These apparently contradictory roles have been suggested to depend on different subsets of DCs that arise from either myeloid or lymphoid hematopoietic origins, respectively. Although DC expression of CD8alpha is attributed to a lymphoid origin, here we show that both CD8alpha+ and CD8alpha- DCs can arise from clonogenic common myeloid progenitors in both thymus and spleen. Thus, expression of CD8alpha is not indicative of a lymphoid origin, and phenotypic and functional differences among DC subsets are likely to reflect maturation status rather than ontogeny.

[Implantable cardioverter/defibrillator: long-term stability of the defibrillation threshold with a unipolar electrode configuration (active-can")]

The majority of cardioverter/defibrillator (ICD) implantations are currently performed with a non-thoracotomy approach. From November 1993 to January 1995, 46 patients underwent implantation of a PCD 7219C with an "active-can" lead configuration at our institution. While the chronic stability of the defibrillation threshold (DFT) for an epicardial lead system is well established, the results are still inconsistent for non-thoracotomy lead systems. Accordingly, the aim of the present study was to compare the acute and chronic defibrillation thresholds of the ICDs implanted with an "active-can" lead system in order to assess the chronic stability of these systems. The defibrillation energy requirements were measured at implant, prior to hospital discharge, three, six and twelve months after implantation of the defibrillator. The patient group consisted of 8 females and 38 males with a mean age of 57.2 years. The mean left ventricular ejection fraction was 43.8%. The most frequent underlying heart disease was coronary artery disease in 31 of 46 patients. Eight patients had idiopathic dilated cardiomyopathy. In 39 of 46 patients, the defibrillation threshold could be successfully determined at all 4 time points after implantation. The mean defibrillation energy requirement at the time of implantation was 9.2 +/- 5.9 Joules (J). The subsequent mean energy requirements were 7.6 +/- 4.8 J at pre-hospital discharge, 8.6 +/- 5.7 J at the 3 month, 8.1 +/- 6.0 J at the 6 month and 8.6 +/- 5.8 J at the 12 month follow-up visits. The mean defibrillation threshold was lowest at the time of prehospital discharge, significantly lower than at the time of initial implantation (p = 0.021). However, at all later time points up to one year, there was no significant difference in the DFT as compared with the time of initial implantation. Comparing the DFT at the time of implantation and the DFT at all other time points, there were no significant differences (9.23 vs. 8.56 J, p = 0.291). Although there was an initial decrease in the DFT at seven to ten days, the long-term stability of the DFT up to one year remained stable in the devices with the "active-can" lead system.

Economic upheaval in 1990-93 and the ecological situation in central Germany

German reunification in 1990 resulted in economic and social upheavals in all of the newly-formed German states. One typical example is the Leipzig-Halle-Bitterfeld region, where many of the industrial plants were fully or partly demolished for economic and technical reasons. Additionally, changes in the political climate led to the closure of a number of major military bases. Despite generally improved environmental standards, dismantling was sometimes accompanied by substantial emissions of chlorinated insecticides and other persistent organic pollutants, as is highlighted for the first time in the present paper. Our analyses are based on a regional biomonitoring net covering 7500 km2 in the Leipzig-Halle-Bitterfeld area during the time period 1990-93. The results enable increased concentrations of airborne contaminants to be attributed to processes linked to the economic upheaval of this time.

Ecotoxicological hazard and risk assessment of heavy metal contents in agricultural soils of central Germany

Heavy metal content of agricultural topsoils has been experimentally determined at 14 areas in the German Leipzig-Halle-Bitterfeld region covering ca. 3700 km2. For most of the locations and elements, the contamination levels are comparable to those of other agricultural sites in Germany and Europe. Application of a sequential extraction technique revealed relatively low contamination levels in the mobile fractions, which indicates a correspondingly low degree of bioavailability of the heavy metals under the current milieu conditions. In contrast, acidification of the soil due to a drastic decrease in the deposition of calciferous fly ash would lead to a significantly increased ecotoxicological hazard potential, as is analyzed by a probabilistic distribution method that quantifies the overlap of normalized exposure and effect data. The discussion includes recommendations for further improvement of risk assessment schemes addressing soil contamination.

Radiofrequency catheter ablation of symptomatic ventricular ectopic beats originating in the right outflow tract

Ectopic activity originating in the right ventricular outflow tract is a frequent finding and may result in severe symptoms such as dyspnea, palpitations, and lack of physical capacity correlated with a low cardiac output. In 12 consecutive symptomatic and drug refractory patients, we performed a study with intracardiac mapping and ablation procedure. The origin of the ectopic beats was identified, and the ablation procedure was performed. Patients were examined by serial ECG, Holter ECG, bicycle ECG, echocardiography, and thoracic X ray. At baseline, the mean number of ectopic beats was 23,823 during Holter ECG. No other arrhythmias were present. Patients underwent basic electro-physiological study, mapping process, and ablation in a single procedure. Ablation was performed with a deflectable thermocoupled catheter with tip electrodes of 4 mm. Criteria for identification of the origin of the ectopic beats included pace mapping with 12 leads and earliest endocardial activation. One male patient suffered from myocarditis; the other 11 patients had no underlying structural heart disease. The mean age was 38 years. Ablation procedure with delivered temperature of 70 degrees C was successful in 11 of 12 patients eliminating the focus. The mean procedural time was 79 +/- 34 minutes; mean fluoroscopy time was 13.8 +/- 8.8 minutes; and mean number of applications was 4.4 +/- 2.8. No adverse effects occurred during a follow-up period of 10 months after ablation. The mean number of ectopic beats per 24 hours after ablation was 317 +/- 599 with a P value of 0.00024. The clinical symptoms improved in all but one patient. One patient had a recurrence after 2 months that could be successfully treated by a second procedure. In our experience, temperature guided radiofrequency catheter ablation is safe and effective for the treatment of patients with symptomatic ectopic activity of the right outflow tract. As long as we lack the experience of a greater patient cohort and a longer follow-up, only drug resistant and highly symptomatic patients should be selected.

[Drug therapy of cardiac arrhythmias 199]

Current antiarrhythmic drug therapy is employed in strict compliance with the proper indication, which is itself limited by the side effects of the available drugs, and modified by the increasing success of such non-drug options as electrical ablation and implantable cardioverters/defibrillators. Drug treatment is restricted to 3 major indications, regular paroxysmal supraventricular tachycardias, atrial flutter and fibrillation, and ventricular tachycardias. Class IA and IC agents are used only to treat supraventricular and ventricular arrhythmias with no structural heart disease. Class III drugs, e.g. sotalol and in particular amiodarone are used preferentially to treat the pre-damaged heart, in particular left-ventricular functional impairment and in coronary heart disease in consideration of their side effects. In the case of the most common treatment-requiring arrhythmia-atrial fibrillation-anticoagulation alone may be indicated. For the prevention of sudden death, beta-blockers continue to be the drugs of first choice.

[Modification of the detection and stimulation behavior of active and passive fixed bipolar pacemaker electrodes by depot dexamethasone]

In a prospective, non-randomised study, two atrial steroid-eluting screw-in leads were evaluated (CapSureFix 4068, Medtronic, n = 17; Accufix II DEC 033-812, Telectronics, n = 16); in the same way, measurements were obtained of three steroid eluting ventricular electrodes (two screw-in leads: CapSureFix 4068, Medtronic, n = 11; Accufix II DEC 033-212, Telectronics, n = 20 and one tined lead Encor DEC 033-448, Telectronics, n = 18). Measurements were performed during implantation (= acute), 7 +/- 3 days after implantation (= subacute) and during follow-up at 3 and 6 months. After atrial implantation, there were no significant differences of the stimulation thresholds (Accufix II DEC: 0.76 +/- 0.23 V-CapSureFix: 0.75 +/- 0.16 V). During follow-up, a slight but not significant increase of the stimulation threshold was observed (Accufix II DEC: subacute 0.99 +/- 0.45 V; 3 months 0.79 +/- 0.43 V; 6 months: 0.84 +/- 0.45 V.-CapSureFix: subacute 0.76 +/- 0.18 V; 3 months 0.87 +/- 0.31 V; 6 months 0.88 +/- 0.32 V). The acute atrial thresholds were significantly lower in the right atrial appendage than in the right lateral wall, while there was no difference during measurements at 3 and 6 months (atrial appendage n = 20 acute 0.69 +/- 0.11 V; right lateral wall n = 13 acute 0.85 +/- 0.25 V). The ventricular Encor DEC and Accufix II DEC electrodes had similar thresholds at implantation, whereas the CapSureFix electrode showed significantly higher stimulation thresholds (Encor DEC 0.56 +/- 0.15 V; Accufix II DEC 0.53 +/- 0.13 V; CapSureFix 0.8 +/- 0.16 V). During follow-up the stimulation threshold increased significantly with each ventricular electrode (Encor DEC: subacute 0.71 +/- 0.22 V; 3 months 0.77 +/- 0.23 V; 6 months 0.8 +/- 0.28 V-Accufix II DEC: subacute 0.86 +/- 0.44 V; 3 months 0.8 +/- 0.25 V; 6 months 0.74 +/- 0.21 V-CapSureFix: subacute 0.92 +/- 0.17 V; 3 months 1.14 +/- 0.46 V; 6 months 1.12 +/- 0.32 V). With regard to the sensing of the intracardiac signals, no differences among the electrodes were detected at the atrial as well as the ventricular level. Subacutely all electrodes had a significant decrease of sensing level without changes after 3 and 6 months (atrium: CapSureFix acute 4.08 +/- 1.34 mV, subacute 3.09 +/- 0.88 mV, 3 months 2.91 +/- 1.02 mV, 6 months 3.0 +/- 1.22 mV; Accufix II DEC acute 4.34 +/- 1.49 mV, subacute 2.86 +/- 1.18 mV, 3 months 3.07 +/- 1.04 mV, 6 months 2.91 +/- 1.16 mV-ventricle: CapSureFix acute 11.55 +/- 4.5 mV, subacute 9.99 +/- 3.51 mV, 3 months 9.36 +/- 3.23 mV, 6 months 9.13 +/- 3.4 mV; Accufix II DEC acute 10.66 +/- 3.0 mV, subacute 7.49 +/- 4.04 mV, 3 months 7.25 +/- 3.64 mV, 6 months 7.52 +/- 4.1 mV; Encor DEC acute 11.65 +/- 3.9 mV, subacute 9.04 +/- 3.29 mV, 3 months 8.69 +/- 3.83 mV, 6 months 8.78 +/- 3.32 mV). The impedance of the Accufix II DEC electrode was significantly lower than the CapSureFix electrode at the time of implantation in the atrium. The ventricular electrodes with active fixation showed a decrease of impedance 7 days after implantation, which diminished during chronic follow-up. On the other hand, the Encor DEC electrode did not exhibit any change of impedance at the different times of determination. In summary, the dexamethasone depots prevented the rise of the stimulation threshold in all the atrial electrodes with active fixation. There remained a small increase of the stimulation threshold after ventricular implantation, which did not reach clinical significance. Thus, the energy saving output of 2.5 volt could be programmed in almost every patient.

Intracranial microembolic signals in 500 patients with potential cardiac or carotid embolic source and in normal controls

BACKGROUND AND PURPOSE

We undertook this study to evaluate the prevalence and clinical correlations of Doppler microembolic signals (MES) in stroke-prone patients.

METHODS

Patients with potential cardiac (n = 300) or carotid (n = 100) embolic source and control subjects (n = 100) were monitored with transcranial Doppler sonography for MES. Transthoracic (n = 192) and/or transesophageal (n = 134) echocardiography and carotid studies (continuous-wave Doppler, n = 181; color-coded duplex, n = 47) were performed in all patients with potential native cardioembolic source. Carotid disease was evaluated by means of continuous-wave Doppler (n = 87), color-coded duplex (n = 70), or intra-arterial angiography (n = 24) in patients with potential carotid embolic source.

RESULTS

Overall MES prevalence was 23% in patients with potential native cardioembolic source (infective endocarditis [n = 7] 43%, left ventricular aneurysm [n = 38] 34%, intracardiac thrombus [n = 23] 26%, dilative cardiomyopathy [n = 39] 26%, nonvalvular atrial fibrillation [n = 24] 21%, valvular disease [n = 80] 15%), 55% in patients with prosthetic cardiac valves (mechanical [n = 77] 58%, porcine [n = 7] 43%, homografts [n = 5] 20%), 28% in patients with carotid disease (symptomatic [n = 46] 52%, asymptomatic [n = 54] 7%; P < .01), and 5% in control subjects. No relationship between MES counts and patients' age, sex, or actual medication was noted. The sensitivity and specificity of MES detection in identifying patients with potential embolic sources were 31% and 95%, respectively.

CONCLUSIONS

Our study confirmed the reported clinical significance of MES in patients with carotid disease and the high specificity of this technique. The demonstrated low sensitivity of MES detection could be due to short monitoring duration or application of antihemostatic treatment. Prospective large-scale studies are needed to determine the definitive value of MES detection as a diagnostic method in patients with potential cardioembolic source.

[Effect of magnesium on sustained ventricular tachycardia]

Intravenous application of magnesium was suggested for the management of persistent ventricular tachycardia. In patients with torsade de pointes tachycardia the injection of magnesium controlled the life threatening arrhythmias reliably, thus magnesium became the treatment of choice in this setting. The results in patients with persistent monomorphic ventricular tachycardia are controversial. In one study, ventricular tachycardias could be controlled in 8 of 10 patients by 2,000 mg magnesium sulfate. In a randomized trial with 43 patients, termination of the ventricular tachycardia could be accomplished in 6 of 20 patients under the influence of 4,000 mg magnesium sulfate, whereas 3 of 24 patients exhibited termination of the tachycardia following placebo; the difference did not reach statistical significance. In our study 4 patients with torsade de pointes tachycardia could be controlled by the application of magnesium glutamate (2 x 1,000 mg intravenously). Of 25 patients with persistent monomorphic ventricular tachycardia, the arrhythmia ended in 8 patients under the influence of magnesium. No significant change of the RR intervals and the QRS duration during ventricular tachycardia could be demonstrated following magnesium injection. Cardiac index during ventricular tachycardia increased from 2.0 +/- 0.6 l/min x m2 to 2.5 +/- 0.1 l/min x m2 (p < 0.05). In a further investigation the dose of magnesium was increased to 2 x 9 mmol. To detect possible interactions with antiarrhythmic agent, 10 patients under chronic antiarrhythmic therapy with class-III-agents were compared with 10 patients without such treatment. Plasma levels of magnesium increased from 0.79 +/- 0.1 mmol/l to 1.87 +/- 0.5 mmol/l. In 5 of the 20 patients ventricular tachycardia ended under the influence of magnesium: 2 patients were on chronic antiarrhythmic agents, whereas 3 had no chronic therapy. There were no significant differences in the RR intervals and the duration of the monophasic action potentials during the ventricular tachycardia under the influence of magnesium. These data indicate that the bolus therapy of magnesium controls persistent monomorphic ventricular tachycardia in a minority of patients only. Therefore, magnesium injection cannot be recommended for treatment of monomorphic ventricular tachycardia in the emergency setting. On the other hand, magnesium application can be considered the therapy of choice for patients with torsade de pointes tachycardia.

The environmental hazard caused by smelter slags from the Sta. Maria de la Paz mining district in Mexico

The noxious potential of metallurgical tailings from the Ag/Pb/Zn/Cu mining district of Sta. María de la Paz (Mexico) is ascertained via the chemical characterization of slag material. Batch experiments using various extraction solutions (e.g. natural rainwater, water rich in humic substances, ammonium nitrate solution) revealed information on the dissolution behaviour of the elements Fe, Mn, Ni, Cu, Zn, As, Ba and Pb from slag with respect of grain size (slag material screened under 2 mm and analytically fine fraction) and elution time (2, 7.5, 24 and 240 h). An initial ecotoxicological assessment of the results is made and the environmental danger caused by large volumes of slag tailings is discussed.

Direct angiography of the coronary sinus: impact on left posteroseptal accessory pathway ablation

The purpose of this study was to determine the incidence and types of venous branches and anomalies in posteroseptal accessory pathways (APs) and whether these findings are indicative for successful ablation sites. Some posteroseptal APs may be located epicardially, or may be associated with venous anomalies or related to the middle cardiac vein. These APs account for many of the failures encountered during endocardial ablation. Direct coronary sinus (CS) angiography was performed in 43 consecutive patients with left posteroseptal APs (n = 23) and in 20 patients with AV nodal reentrant tachycardia prior to catheter ablation. In 14 (61%) of 23 APs, a venous branch or an anomaly of the CS was found in the posteroseptal region (6 with middle cardiac vein, 2 with other ventricular venous branches, and 6 had a diverticulum). Eleven (48%) of 23 APs were successfully abolished from within that demonstrated venous system, with a median of four radiofrequency impulses. In the remaining 12 (52%) patients, ablation was attempted from the endocardial site of the mitral annulus. Repeat angiography after energy delivery revealed no major complications in any patient. One (5%) patient with AV nodal reentrant tachycardia had evidence of a CS anomaly (P < 0.01). Various types of venous branches and anomalies are associated with the majority of patients with left posteroseptal APs. The APs are directly related to these complex findings, and AP conduction can easily be eliminated from within the venous branches. CS angiography is suggested prior to catheter ablation of left posteroseptal APs to facilitate the ablation procedure.

Changes in the amplitude of endocardial electrograms following defibrillator discharge: comparison of two lead systems

Changes in the amplitude of endocardial electrograms after an unsuccessful shock attempt have been demonstrated to cause failure of redetection of ventricular fibrillation in patients using an integrated sense-pace defibrillating lead system. Thus, the objective of this study was to compare the effects of defibrillator shocks on the amplitude of endocardial electrograms in 26 patients using two different nonthoracotomy systems, a previous lead (model 0062) or a redesigned version (model 0072). At implant, bipolar endocardial electrograms were obtained before each shock application, during initial detection and redetection of ventricular fibrillation in case the applied shock was unsuccessful, and during intervals of 5, 10, 20, 30, 60, and 120 seconds after each shock delivery. No significant difference was noted in endocardial amplitudes between the lead models 0062 and 0072 during baseline sinus rhythm (12.2 +/- 4.6 mV vs 11.4 +/- 3.8 mV), and during initial ventricular fibrillation (7.0 +/- 2.4 mV vs 7.6 +/- 2.3 mV). During redetection of ventricular fibrillation, however, there was a significant difference (P = 0.0006) in endocardial amplitudes (3.4 +/- 1.9 mV vs 6.6 +/- 2.3 mV) between both leads tested. Comparing lead models 0062 and 0072, marked differences were found in endocardial amplitudes during sinus rhythm 5, 10, and 20 seconds after successful arrhythmia termination: 2.8 +/- 1.9 mV vs 8.6 +/- 2.9 mV (P < 0.0001), 4.6 +/- 2.9 mV vs 9.2 +/- 3.2 mV (P = 0.0007), and 6.4 +/- 4.0 mV vs 10.5 +/- 3.6 mV (P = 0.01). At predischarge testing, failure of redetection of ventricular fibrillation was documented in two patients with the lead model 0062 requiring external defibrillation to restore sinus rhythm. These findings demonstrate a significant less postshock attenuation of the endocardial electrogram amplitudes during persistent ventricular fibrillation after an unsuccessful shock attempt as well as during sinus rhythm immediately following an effective shock delivery using the redesigned lead system model 0072 compared to the electrogram amplitudes obtained in patients using the previous lead model 0062.

Incidence of ICD lead related complications during long-term follow-up: comparison of epicardial and endocardial electrode systems

The aim of this study was to evaluate the long-term stability of epicardial and endocardial lead systems for third-generation cardioverter defibrillators (ICDs) and to assess the usefulness of diagnostic tools. One hundred forty patients with 61 epicardial (43.6%) and 79 nonthoracotomy systems (56.4%) were followed for 25 +/- 19 months. A total of 18 (12.9%) lead related complications were documented. Complications of epicardial systems were detected in 10 patients (16.4%) during a follow-up time of 36 +/- 8 months: crinkling of patch electrodes in 6 patients (9.8%), insulation breakage of sensing electrodes in 2 patients (3.3%), and adapter defect in 2 patients (3.3%). Eight of the patients (10.1%) with transvenous-subcutaneous systems had lead related complications during a 13 +/- 6 months follow-up: fracture of the subcutaneous patch lead in 2 patients (2.5%), dislodgement of the right ventricular lead in 2 patients (2.5%), dislodgement of the superior vena cava lead in 2 patients (2.5%), insulation breakage of sensing electrodes in 1 patient (1.3%), and connector defect in 1 patient (1.3%). There was no significant difference in the incidence of lead related complications between epicardial and endocardial systems (P > 0.05). Fractures, dislodgements, and crinklings were documented within the first 8 +/- 5 months by regular chest X ray. Defects of insulation, adapter, or connector were detected 22 +/- 10 months after implantation and were associated with delivery of multiple inappropriate ICD therapies. An operative lead revision was indicated for 4 epicardial (6.6%) and 6 endocardial (7.6%) lead systems.

CONCLUSIONS

Endocardial lead systems offer a similar long-term stability as compared to epicardial lead systems. Chest X ray is the most useful tool to detect lead fracture, dislodgment, and patch crinkling. Marker recordings or real-time electrograms have not been helpful in this series to identify patients with suspected lead defects prior to the experience of inappropriate ICD discharges.

Heart rate to work rate relation throughout peak exercise in normal subjects as a guideline for rate-adaptive pacemaker programming

We investigated the physiologic heart rate (HR) to work rate (WR) relation throughout peak exercise in normal subjects as a guideline for rate-adaptive pacemaker slope programming. The study group consisted of 41 middle-aged subjects (22 men and 19 women) without evidence of cardiopulmonary disease. Peak-exercise stress tests were performed on a calibrated treadmill by using the symptom-limited "ramping incremental treadmill exercise" (RITE) protocol. The HR response, oxygen uptake, and treadmill workload increments were assessed simultaneously. The HR/WR slope, as determined using linear regression analysis, was 0.37 +/- 0.13 beats/min/W for the entire study group, which indicates an upper range increase of 5 beats/10 W increase of external treadmill work performed, using the mean value +/- 1 SD. Men generated an HR/WR slope of 0.32 +/- 0.09 beats/min/W, and women, 0.43 +/- 0.15 beats/min/W, indicating a significant sex-related difference in the HR/WR relation (p < 0.01). Thus, to achieve an appropriate matching of HR with patient effort, rate-adaptive pacemakers should generate an average increase of approximately 5 beats per increase in 10 W of external treadmill work. The HR/WR relation can easily be determined to provide the clinician with a minimal check system to avoid a hyper- or hypochronotropic paced response to exercise.

Slowing of the ventricular rate during atrial fibrillation by ablation of the slow pathway of AV nodal reentrant tachycardia

INTRODUCTION

The mechanisms whereby radiofrequency catheter modification of AV nodal conduction slows the ventricular response are not well defined. Whether a successful modification procedure can be achieved by ablating posterior inputs to the AV node or by partial ablation of the compact AV node is unclear. We hypothesized that ablation of the well-defined slow pathway in patients with AV nodal reentrant tachycardia would slow the ventricular response during atrial fibrillation.

METHODS AND RESULTS

In 34 patients with dual AV physiology and inducible AV nodal reentrant tachycardia, atrial fibrillation was induced at baseline and immediately after successful slow pathway ablation and at 1-week follow-up. The minimal, maximal, and mean RR intervals during atrial fibrillation increased from 353 +/- 76, 500 +/- 121, and 405 +/- 91 msec to 429 +/- 84 (P < 0.01), 673 +/- 161 (P < 0.01), and 535 +/- 98 msec (P < 0.01), respectively. These effects remained stable during follow-up at 1 week. The AV block cycle length increased from 343 +/- 68 msec to 375 +/- 60 msec (P < 0.05) immediately and to 400 +/- 56 msec (P < 0.01) at 1-week follow-up. The effective refractory period of the AV node prolonged from 282 +/- 83 msec to 312 +/- 89 msec and to 318 +/- 81 msec after 1 week (P < 0.05), respectively.

CONCLUSION

This study shows a decrease in ventricular response to pacing-induced atrial fibrillation after ablation of the slow pathway in patients with AV nodal reentrant tachycardia. Since the AV nodal conduction properties could be defined, this study supports the hypothesis that the main mechanism of AV nodal modification in chronic atrial fibrillation is caused by ablation of posterior inputs to the AV node.