Diagnostic performance of coronary CTA and CT-FFR for the detection of coronary artery disease in routine TAVI work-up

Objectives

To assess the diagnostic performance of CT-FFR for the diagnosis of CAD in the work-up for TAVI.

Background

Work-up for transcatheter aortic valve implantation (TAVI) currently utilizes computed tomography (CT) to evaluate annulus diameter and peripheral vascular access, plus invasive coronary angiography (ICA) to assess significant coronary artery disease (CAD). ICA might partially be redundant with the use of Coronary CT Angiography (CCTA). Prior studies found improvement of the diagnostic accuracy of CCTA by use of CT derived fractional flow reserve (CT-FFR).

Methods

Consecutive patients with severe symptomatic aortic valve stenosis who underwent TAVI work-up between 2015–2019 were included in this cross-sectional study. All patients underwent CCTA and ICA within 3 months and diagnostic performance of both CCTA and CT-FFR were assessed using ICA as reference.

Results

Seventy-six of the 338 patients included in the analysis had ≥1 significant coronary stenosis at ICA. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy per-patient were 76.9%, 64.5%, 34.0%, 92.1% and 66.9% for CCTA and 84.6%, 88.3%, 63.2%, 96.0% and 87.6% for CT-FFR. The area under the receiver-operating characteristic-curve significantly differ between CCTA and CT-FFR (0.84 versus 0.90 p=0.02). A CT-FFR guided approach could avoid ICA in 57.1% versus 43.6% using CCTA.

Conclusions

CT-FFR significantly improves the diagnostic accuracy of CCTA without additional testing and increases the proportion of patients in whom ICA could have been safely avoided It has the potential to be integrated in the current clinical work-up for TAVI for diagnosing stable CAD requiring treatment.

Funding Acknowledgement

Type of funding sources: None.

Determinants of myocardial injury following transcatheter aortic valve implantation: a pre-specified substudy from the POPular TAVI trial

Background

Myocardial injury is frequently observed in patients undergoing transcatheter aortic valve implantation (TAVI) and has been linked to worse prognosis [1,2]. Yet, knowledge concerning the underlying mechanisms and preventive strategies is scarce.

Purpose

To identify clinical determinants and the effect of periprocedural antithrombotic strategies on markers of myocardial injury after TAVI.

Methods

The POPular TAVI trial was a prospective, open label, multicentre randomized controlled trial, investigating the addition of clopidogrel to aspirin (cohort A) or oral anticoagulation (OAC) (cohort B) in patients undergoing TAVI [3] Patients randomised to clopidogrel received a 300mg loading dose before TAVI, followed by a 75mg maintenance dose once daily. In patients using OAC, this was continued during TAVI with an international normalized ratio aimed at 2.0. All OAC patients used a vitamin-K antagonist. Blood samples were taken at baseline, 6, 24, 48, and 72 hours following TAVI to determine myocardial injury using Creatine Kinase-MB (CK-MB) and high-sensitive cardiac troponin T (hs-cTnT) according to the VARC-2 criteria. Also, baseline and procedural variables were collected in detail. A linear mixed effects model was used for pair-wise analysis of the changes in enzyme levels at different time points between groups. Regression analysis was performed using the logistic regression model. Statistical analyses were performed using R (version 3.4.1).

Results

In total, 131 patients undergoing transfemoral TAVI were included at two study sites, of whom 63 (48%) received clopidogrel and 68 (52%) did not. Almost half of the patients (45%) were on OAC. The rise in CK-MB (mean peak 23.4±13.3 U/l) and hs-cTnT (mean peak of 0.23±0.33 ug/) was maximal at 6 and 24 hours, respectively. The CK-MB and hs-cTnT levels did not differ between the clopidogrel and no clopidogrel group at any time point (figure 1). Myocardial injury occurred in 18 (30.1%) patients receiving OAC versus 39 (54.2%) patients not receiving OAC (p=0.007). The course of hs-cTnT reached higher levels in patients with chronic kidney disease (p<0.001) and in patients with a preserved left ventricular ejection fraction (LVEF) (p=0.008). Also, the use of a controlled mechanical expanding prosthesis was associated with a higher rise of hs-cTnT (p=0.007). (Figure 2) In multivariable analysis, predictors of a maximal increase in hs-cTnT were a preserved LVEF (OR 1.15, 95% CI 1.02–1.30) and chronic kidney disease (OR 1.13, 95% CI 1.01–1.28). Other procedural factors, like balloon dilation and rapid ventricular pacing, were not associated with myocardial injury.

Conclusions

The addition of clopidogrel to aspirin or OAC during TAVI was not associated with a reduction in myocardial injury. Instead, OAC therapy, as compared to aspirin, was associated with a reduction in rise and fall of hs-cTnT. Also, patients with a preserved LVEF or chronic kidney disease observed higher levels of hs-cTnT.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): ZonMWSt. Antonius Research Fund

Major threats to early safety after transcatheter aortic valve implantation in a contemporary cohort of real-world patients

INTRODUCTION

Despite considerable advances in the last decade, major adverse events remain a concern after transcatheter aortic valve implantation (TAVI). The aim of this study was to provide a detailed overview of their underlying causes and contributing factors in order to identify key domains for quality improvement.

METHODS

This observational, prospective registry included all patients undergoing TAVI between 31 December 2015 and 1 January 2020 at the St. Antonius Hospital in Nieuwegein and the University Medical Centre in Utrecht. Outcomes of interest were all-cause mortality, stroke, major bleeding, life-threatening or disabling bleeding, major vascular complications, myocardial infarction, severe acute kidney injury and conduction disturbances requiring permanent pacemaker implantation within 30 days after TAVI, according to the Valve Academic Research Consortium‑2 criteria.

RESULTS

Of the 1250 patients who underwent TAVI in the evaluated period, 146 (11.7%) developed a major complication. In 54 (4.3%) patients a thromboembolic event occurred, leading to stroke in 36 (2.9%), myocardial infarction in 13 (1.0%) and lower limb ischaemia in 11 (0.9%). Major bleeding occurred in 65 (5.2%) patients, most frequently consisting of acute cardiac tamponade (n = 25; 2.0%) and major access-site bleeding (n = 21; 1.7%). Most complications occurred within 1 day of the procedure. Within 30 days a total of 54 (4.3%) patients died, the cause being directly TAVI-related in 30 (2.4%). Of the patients who died from causes that were not directly TAVI-related, 14 (1.1%) had multiple hospital-acquired complications.

CONCLUSION

A variety of underlying mechanisms and causes form a wide spectrum of major threats affecting early safety in 11.7% of patients undergoing TAVI in a contemporary cohort of real-world patients.

Transcatheter aortic valve replacement: impact of pre-procedural FEops HEARTguide assessment on device size selection in borderline annulus size cases

OBJECTIVES

The aim of this study is to evaluate device size selection in patients within the borderline annulus size range undergoing transcatheter aortic valve replacement (TAVR) and to assess if pre-procedural patient-specific computer simulation will lead to the selection of a different device size than standard of care.

BACKGROUND

In TAVR, appropriate device sizing is imperative. In borderline annulus size cases no standardised technique for tailored device size selection is currently available. Pre-procedural patient-specific computer simulation can be used, predicting the risk for paravalvular leakage (PVL) and need for permanent pacemaker implantation (PPI).

METHODS

In this multicentre retrospective study, 140 patients in the borderline annulus size range were included. Hereafter, device size selection was left to the discretion of the operator. After TAVR, in 24 of the 140 patients, patient-specific computer simulation calculated the most appropriate device size expected to give the lowest risk for PVL and need for PPI. In these 24 patients, device size selection based on patient-specific computer simulation was compared with standard-of-care device size selection relying on a standardised matrix (Medtronic).

RESULTS

In a significant proportion of the 140 patients (26.4%) a different device size than recommended by the matrix was implanted. In 10 of the 24 patients (41.7%) in whom a computer simulation was performed, a different device size was recommended than by means of the matrix.

CONCLUSIONS

Device size selection in patients within the borderline annulus size range is still ambiguous. In these patients, patient-specific computer simulation is feasible and can contribute to a more tailored device size selection.

Gamification of health professions education: a systematic review

Gamification refers to using game attributes in a non-gaming context. Health professions educators increasingly turn to gamification to optimize students' learning outcomes. However, little is known about the concept of gamification and its possible working mechanisms. This review focused on empirical evidence for the effectiveness of gamification approaches and theoretical rationales for applying the chosen game attributes. We systematically searched multiple databases, and included all empirical studies evaluating the use of game attributes in health professions education. Of 5044 articles initially identified, 44 met the inclusion criteria. Negative outcomes for using gamification were not reported. Almost all studies included assessment attributes (n = 40), mostly in combination with conflict/challenge attributes (n = 27). Eight studies revealed that this specific combination had increased the use of the learning material, sometimes leading to improved learning outcomes. A relatively small number of studies was performed to explain mechanisms underlying the use of game attributes (n = 7). Our findings suggest that it is possible to improve learning outcomes in health professions education by using gamification, especially when employing game attributes that improve learning behaviours and attitudes towards learning. However, most studies lacked well-defined control groups and did not apply and/or report theory to understand underlying processes. Future research should clarify mechanisms underlying gamified educational interventions and explore theories that could explain the effects of these interventions on learning outcomes, using well-defined control groups, in a longitudinal way. In doing so, we can build on existing theories and gain a practical and comprehensive understanding of how to select the right game elements for the right educational context and the right type of student.

Incidence and outcome of prosthetic valve endocarditis after transcatheter aortic valve replacement in the Netherlands

Background

Transcatheter aortic valve replacement (TAVR) is increasingly being used as an alternative to conventional surgical valve replacement. Prosthetic valve endocarditis (PVE) is a rare but feared complication after TAVR, with reported first-year incidences varying from 0.57 to 3.1%. This study was performed to gain insight into the incidence and outcome of PVE after TAVR in the Netherlands.

Methods

A multicentre retrospective registry study was performed. All patients who underwent TAVR in the period 2010–2017 were screened for the diagnosis of infective endocarditis in the insurance database and checked for the presence of PVE before analysis of general characteristics, PVE parameters and outcome.

Results

A total of 3968 patients who underwent TAVR were screened for PVE. During a median follow-up of 33.5 months (interquartile range (IQR) 22.8–45.8), 16 patients suffered from PVE (0.4%), with a median time to onset of 177 days (IQR 67.8–721.3). First-year incidence was 0.24%, and the overall incidence rate was 0.14 events per 1000 person-years. Overall mortality during follow-up in our study was 31%, of which 25% occurred in hospital. All patients were treated conservatively with intravenous antibiotics alone, and none underwent a re-intervention. Other complications of PVE occurred in 5 patients (31%) and included aortic abscess (2), decompensated heart failure (2) and cerebral embolisation (1).

Conclusion

PVE in patients receiving TAVR is a relatively rare complication and has a high mortality rate.

4289Clinical outcomes of percutaneous mitral valve repair in secondary mitral regurgitation: a systematic review and meta-analysis

Background

The benefit of percutaneous mitral valve repair with mitraclip (PMVR) in patients with secondary mitral regurgitation (MR) is still debated.

Methods

In order to compare the outcome of PMVR with optimal medical therapy (OMT) versus OMT alone in patients with secondary MR, we performed a systematic review and meta-analysis of 2 randomized clinical trials (RCT) and 7 non-randomized observational studies (nROS). Hazard ratios (HR) and 95% confidence intervals (CI) were pooled through inverse variance random-effect model to compute the summary effect size for all-cause mortality, cardiovascular death and cardiac-related hospitalization. Subgroup and meta-regression analysis were also performed.

Results

An overall population of 3,118 individuals (67% men; mean age, 73 years) was included: 1,775 PMVR+OMT and 1,343 OMT patients, with mean follow-up of 24±15 months. PMVR+OMT was associated with a lower risk of all-cause death (HR: 0.77; 95% CI: 0.68–0.87), cardiovascular death (HR: 0.55; 95% CI: 0.34–0.89) and cardiac-related hospitalization (HR: 0.77; 95% CI: 0.64–0.92). Meta-regression analysis showed that larger left ventricular end-diastolic volume index (LVEDVI) portends higher mortality after PMVR (p<0.001).

Conclusions

This study-level meta-analysis shows that PMVR+OMT is associated with reduced all-cause death, cardiovascular death and cardiac-related hospitalization when compared with OMT alone in secondary MR. LVEDVI is a predictive marker of efficacy, as patients with smaller LVEDVI derive the largest benefit from PMVR.

Sex differences in characteristics and outcome in acute coronary syndrome patients in the Netherlands

Background

Sex differences in acute coronary syndrome (ACS) have been reported, but little is known about the situation in the Netherlands.

Methods

This registry is a merge of available data on ACS patients in the electronic data capture systems of 11 centres with 24/7 interventional cardiology services. We included patients >18 years undergoing a cardiac catheterisation between 2010–2012. We evaluated sex differences in clinical and procedural characteristics and 1‑year mortality.

Results

A total of 29,265 ACS patients (8,720 women and 20,545 men) were registered. Women were on average 4.5 years older (68.5 vs 63.0 years, p < 0.001) and had a higher prevalence of hypertension (62.7 vs 49.8%, p < 0.001) and insulin-dependent diabetes mellitus (9.6 vs 6.8%, p < 0.001) than men. Women less often presented with ST-elevation myocardial infarction (43.7% vs 47.6%, p < 0.001) and appeared to have less extensive coronary artery disease than men. Women less often underwent coronary angiography by radial access (52.5 vs 55.9%, p < 0.001). One-year mortality was higher in women than in men (7.3% and 5.6%, p < 0.001). More specific, the relationship between sex and mortality was age-dependent and showed higher mortality in women ≤71 years, but lower mortality in older women compared with men (p-interaction <0.001).

Conclusion

We found differences in clinical and procedural characteristics and outcome between women and men admitted for ACS, which are in line with other Western countries. The limitations of our registry, based on existing local databases, can be overcome by the use of the prospective Netherlands Heart Registry that is currently in development.

Electronic supplementary material

The online version of this article (10.1007/s12471-019-1271-0) contains supplementary material, which is available to authorized users.

Bid chimeras indicate that most BH3-only proteins can directly activate Bak and Bax, and show no preference for Bak versus Bax

The mitochondrial pathway of apoptosis is initiated by Bcl-2 homology region 3 (BH3)-only members of the Bcl-2 protein family. On upregulation or activation, certain BH3-only proteins can directly bind and activate Bak and Bax to induce conformation change, oligomerization and pore formation in mitochondria. BH3-only proteins, with the exception of Bid, are intrinsically disordered and therefore, functional studies often utilize peptides based on just their BH3 domains. However, these reagents do not possess the hydrophobic membrane targeting domains found on the native BH3-only molecule. To generate each BH3-only protein as a recombinant protein that could efficiently target mitochondria, we developed recombinant Bid chimeras in which the BH3 domain was replaced with that of other BH3-only proteins (Bim, Puma, Noxa, Bad, Bmf, Bik and Hrk). The chimeras were stable following purification, and each immunoprecipitated with full-length Bcl-x_L according to the specificity reported for the related BH3 peptide. When tested for activation of Bak and Bax in mitochondrial permeabilization assays, Bid chimeras were ~1000-fold more effective than the related BH3 peptides. BH3 sequences from Bid and Bim were the strongest activators, followed by Puma, Hrk, Bmf and Bik, while Bad and Noxa were not activators. Notably, chimeras and peptides showed no apparent preference for activating Bak or Bax. In addition, within the BH3 domain, the h0 position recently found to be important for Bax activation, was important also for Bak activation. Together, our data with full-length proteins indicate that most BH3-only proteins can directly activate both Bak and Bax.

Everolimus- and sirolimus-eluting stents in patients with and without ST-segment elevation myocardial infarction

Aims

Everolimus-eluting stents (EES) were superior to sirolimus-eluting stents (SES) in a dedicated myocardial infarction trial, a finding that was not observed in trials with low percentages of ST-elevation myocardial infarction (STEMI). Therefore, this study sought to investigate the influence of clinical presentation on outcome after EES and SES implantation.

Methods

A pooled population of 1602 randomised patients was formed from XAMI (acute MI trial) and APPENDIX-AMI (all-comer trial). Primary outcome was cardiac mortality, MI and target vessel revascularisation at 2 years. Secondary endpoints included definite/probable stent thrombosis (ST). Adjustment was done using Cox regression.

Results

In total, 902 EES and 700 SES patients were included, of which 44 % STEMI patients (EES 455; SES 257) and 56 % without STEMI (EES 447; SES 443). In the pooled population, EES and SES showed similar outcomes during follow-up. Moreover, no differences in the endpoints were observed after stratification according to presentation. Although a trend toward reduced early definite/probable ST was observed in EES compared with SES in STEMI patients, long-term ST rates were low and comparable.

Conclusions

EES and SES showed a similar outcome during 2-year follow-up, regardless of clinical presentation. Long-term safety was excellent for both devices, despite wide inclusion criteria and a large sub-population of STEMI patients.

Mitotic catastrophe triggered in human cancer cells by the viral protein apoptin

Mitotic catastrophe is an oncosuppressive mechanism that senses mitotic failure leading to cell death or senescence. As such, it protects against aneuploidy and genetic instability, and its induction in cancer cells by exogenous agents is currently seen as a promising therapeutic end point. Apoptin, a small protein from Chicken Anemia Virus (CAV), is known for its ability to selectively induce cell death in human tumor cells. Here, we show that apoptin triggers p53-independent abnormal spindle formation in osteosarcoma cells. Approximately 50% of apoptin-positive cells displayed non-bipolar spindles, a 10-fold increase as compared to control cells. Besides, tumor cells expressing apoptin are greatly limited in their progress through anaphase and telophase, and a significant drop in mitotic cells past the meta-to-anaphase transition is observed. Time-lapse microscopy showed that mitotic osteosarcoma cells expressing apoptin displayed aberrant mitotic figures and/or had a prolonged cycling time during mitosis. Importantly, all dividing cells expressing apoptin eventually underwent cell death either during mitosis or during the following interphase. We infer that apoptin can efficiently trigger cell death in dividing human tumor cells through induction of mitotic catastrophe. However, the killing activity of apoptin is not only confined to dividing cells, as the CAV-derived protein is also able to trigger caspase-3 activation and apoptosis in non-mitotic cancer cells.

Effect of spinal cord stimulation on heart rate variability and myocardial ischemia in patients with chronic intractable angina pectoris--a prospective ambulatory electrocardiographic study

BACKGROUND AND HYPOTHESIS

Spinal cord stimulation is an effective treatment for chronic refractory angina pectoris. Its efficacy is related to an anti-ischemic action, possibly as a result of modulation of the autonomic nervous system. Therefore, the influence of spinal cord stimulation on the autonomic nervous system and myocardial ischemia was prospectively studied in 19 consecutive patients with intractable angina pectoris.

METHODS

Patients were included when demonstrating > 0.1 mV STsegment depression on the exercise electrocardiogram (ECG) during two separate treadmill tests. After enrollment, heart rate variability together with ischemic indices were studied with 48 h ambulatory ECG monitoring. Assessments were made at baseline and after 6 weeks of spinal cord stimulation therapy.

RESULTS

After 6 weeks, no significant changes in heart rate variability were detected. However, ischemic indices on the ambulatory ECG, as well as anginal attacks and consumption of sublingual nitrate tablets, were significantly decreased.

CONCLUSION

Autonomic modulation assessable with heart rate variability analysis may not be the explanatory mechanism of action for the decrease of anginal attacks and ischemia, exerted by spinal cord stimulation used as an adjuvant therapy in patients with chronic intractable angina pectoris.

[The Nobel Prize in Chemistry for 2006 for molecular unravelment of DNA transcription]

This year's Nobel Prize in Chemistry has been awarded to Roger D.Kornberg for his ground-breaking research into the structural basis of transcription. Transcription is the process by which the enzyme RNA polymerase II copies specific genetic information to messenger-RNA. This messenger-RNA is used in the translation of genetic information into the proteins it codes for. Kornberg described tens of proteins relevant to the transcription process. He developed and optimalized methods that finally led to the complete clarification of the atomic structure of RNA polymerase. Kornberg's work has provided more insight into the various stages of the transcription process and possible disruptions that lead to illness.

Difference in long-term prognostic value of renal function between ischemic and non-ischemic mild heart failure

INTRODUCTION

Renal function is one of the strongest prognostic markers in patients with chronic heart failure, but it has been suggested that this might be due to (local, i.e. renal) vascular atherosclerosis. The aim of the present study is to evaluate the prognostic value of renal function in both ischemic and non-ischemic mild chronic heart failure.

METHODS

From 161 patients with early chronic heart failure and NYHA class II, who had been enrolled in a multicenter trial, ischemic chronic heart failure was present in 120 patients and non-ischemic chronic heart failure in 41 patients. Estimated glomerular filtration rate was calculated by the Cockcroft-Gault equation (GFRc).

RESULTS

Follow-up duration was 13 years (mean 11.7 years). Mean age was 60.5+/-8.0 years, 86% was male and mean left ventricular ejection fraction was 0.29+/-0.08. Baseline characteristics were not statistically different between the groups. Multivariate Cox regression analysis revealed that in non-ischemic chronic heart failure, renal function was an important predictor of all-cause mortality (Relative Risk; 1.65 (1.05-2.58); p=0.029). In contrast, in ischemic chronic heart failure, renal function was not related to all-cause mortality (Relative Risk; 1.07 (0.92-1.23); p=0.40).

CONCLUSION

In mild chronic heart failure, renal function is a prognostic risk marker for long-term mortality in non-ischemic chronic heart failure, but not in patients with coronary artery disease. These data suggest that renal vascular abnormalities are not primarily responsible for the prognostic value of renal function in patients with mild chronic heart failure.

Screening for distant metastases in patients with head and neck cancer: what is the current clinical practice?

OBJECTIVES

The detection of distant metastases during screening influences the choice of treatment in patients with head and neck squamous cell carcinoma (HNSCC). There is no consensus on the diagnostic technique that has to be used nor on the subgroup of HNSCC patients that may benefit from screening.

DESIGN

Questionnaire on current practice concerning the diagnostic work-up in HNSCC patients for screening for distant metastases.

PARTICIPANTS

Investigators in the 12 otolaryngology / head and neck and seven oromaxillofacial departments treating head and neck cancer in the Netherlands.

RESULTS

The response rate was 100%. Indications for screening were cervical lymph node metastases (63%), mutilating surgery (58%), locoregional recurrence (47%), advanced T-stage (32%), second primary tumour (21%). Diagnostic techniques routinely used for screening besides chest X-ray were chest CT (84%), liver ultrasound (53%), liver CT (16%) and bone scintigraphy (42%). Forty-two per cent of the clinicians were not satisfied with the current methods of screening.

CONCLUSION

This survey shows a substantial variation in indications and diagnostic techniques used for screening for distant metastases between the major institutions treating head and neck cancer in the Netherlands. There is a need for guidelines for screening for distant metastases in patients with head and neck cancer.

Daily induction combination treatment with alpha 2b interferon and ribavirin or standard combination treatment in naive chronic hepatitis C patients. A multicentre randomized controlled trial

The standard treatment for patients with chronic hepatitis C is a 6-12-month combination therapy with interferon alpha and ribavirin. Induction treatment could result in a faster early decline of the hepatitis C virus (HCV) load and a better response rate. Naive chronically infected HCV patients (n = 454) were randomized into two arms to receive either induction treatment with interferon alpha 2b 5 million units (MU) subcutaneously (s.c.) daily during a period of 8 weeks (arm A); or treatment with interferon alpha 2b 5 MU s.c. three times a week (TIW) for a period of 8 weeks (arm B). After week 8, interferon treatment in both arms was 3 MU s.c. TIW for a total period of 12 months. In both arms, ribavirin (1000-1200 mg orally per day) was added at week 4. Induction treatment resulted in a higher virological response at week 8 of treatment (66%vs 47%; P < 0.01). However, response at the end of treatment and at 6 months follow-up was not different (53%vs 50%, 41%vs 33%). The occurrence of adverse events and the drop-out rate were similar in both arms. Although an early virological response is observed more frequently in the induction treatment, end of treatment response and sustained responses did not differ.

Cardiac failure following group A streptococcal infection with echocardiographically proven pericarditis, still insufficient arguments for acute rheumatic fever: a case report and literature update

We recently encountered a 49-year-old female who developed fever due to group A streptococcal (GAS) bacteriaemia spreading to an abscess in the iliac muscle and a bacterial monarthritis of the right knee with a sterile arthritis of her left knee. Treatment was started with a six-week course of intravenous penicillin. She developed a mitral valve insufficiency and pericarditis on the tenth day of admission. In the third week heart failure developed with, on echocardiograph, a high output left ventricular failure without signs of valvulitis or myocarditis. Using a diuretic regimen she was recompensated. Because of the pericarditis with mitral valve insufficiency corticosteroids were given, which had a rapid beneficial effect. A discussion follows on the position of acute rheumatic fever versus post-streptococcal reactive arthritis in this clinical picture and the literature is updated.

A large family characterised by nocturnal sudden death

BACKGROUND

We recently identified a novel mutation in large family characterised by premature nocturnal sudden death. In the present paper we provide an overview of the findings in this family.

METHODS

From 1958 onwards, when the first patient presented, we collected clinical data on as many family members as possible. After identification in 1998 of the underlying genetic disorder (SCN5A, 1795insD), genotyping was performed diagnostically.

RESULTS

Since 1905 unexplained sudden death occurred in 26 family members, 17 of whom died during the night. Besides sudden death, symptomatology was rather limited; only six patients reported syncopal attacks. In one of them, a 13-year-old boy, asystolic episodes up to nine seconds were documented. Until now, the mutation has been found in 114 family members (57 males, 57 females). Carriers of the mutant gene exhibited bradycardia-dependent QT-prolongation, intrinsic sinus node dysfunction, generalised conduction abnormalities, a paucity of ventricular ectopy, and the Brugada sign. Cardiomyopathy or other structural abnormalities were not found in any of the carriers. Electrophysiological studies showed that mutant channels were characterised by markedly reduced I_Na amplitude, a positive shift of voltage-dependence of activation and a substantial negative shift of voltage-dependence of inactivation of I_Na. From 1978 onwards, a pacemaker for anti-brady pacing was implanted for prevention of sudden death. In patients in whom a prophylactic pacemaker was implanted no unexplained sudden death occurred, whereas 5 sudden deaths occurred in the group of patients who did not receive a pacemaker.

CONCLUSION

We have described a large family with a SCN5A-linked disorder (1795insD) with features of LQT₃, Brugada syndrome and familial conduction system disease. Anti-brady pacing was successful in preventing sudden death. The mode of death is possibly bradycardic.

Prediction of 6 months left ventricular dilatation after myocardial infarction in relation to cardiac morbidity and mortality. Application of a new dilatation model to GISSI-3 data

AIMS

To predict the long-term left ventricular volume index early after myocardial infarction and to investigate the relationship between long-term left ventricular dilatation risk and clinical outcome.

METHODS AND RESULTS

By applying a previously developed dilatation model, we predicted the 6-month left ventricular volume index early after myocardial infarction (median 9 days) in 13,679 GISSI-3 patients, to identify patients at high risk of long-term left ventricular dilatation. The left ventricular systolic and diastolic volume indexes at 6 months were predicted with r=0.72 and r=0.68, respectively, in the subgroup of patients in whom a pre-discharge echo was available (n=7842). Patients predicted to be at risk for long-term left ventricular dilatation had an increased risk of mortality (RR 1.87, 95% CI: 1.48 to 2.36) and heart failure at 6 months (RR 2.59, 95% CI:2.04 to 3.28), but no increased risk of reinfarction at 6 months (RR 1.12, 95% CI: 0.87 to 1.45) or of angina pectoris (RR 1.07, 95% CI: 0.95 to 1.20).

CONCLUSION

Our prediction of long-term left ventricular dilatation, obtained by applying our new dilatation model in over 13,000 GISSI-3 patients, correlated well with mortality and heart failure after myocardial infarction. Therefore, our new dilatation model may contribute to more efficient risk stratification early after myocardial infarction.

One-pot two-step enzymatic coupling of pyrimidine bases to 2-deoxy-D-ribose-5-phosphate. A new strategy in the synthesis of stable isotope labeled deoxynucleosides

The enzymatic synthesis of thymidine from 2-deoxy-D-ribose-5-phosphate is achieved, in a one-pot two-step reaction using phosphoribomutase (PRM) and commercially available thymidine phosphorylase (TP). In the first step the sugar-5-phosphate is enzymatically rearranged to alpha-2-deoxy-D-ribose-1-phosphate. Highly active PRM is easily obtained from genetically modified overproducing E. coli cells (12,000 units/84 mg protein) and is used without further purification. In the second step thymine is coupled to the sugar-1-phosphate. The thermodynamically unfavorable equilibrium is shifted to the product by addition of MnCl(2) to precipitate inorganic phosphate. In this way the overall yield of the beta-anomeric pure nucleoside increases from 14 to 60%. In contrast to uracil, cytosine is not accepted by TP as a substrate. Therefore, 2'-deoxy-cytidine is obtained by functional group transformations of the enzymatically prepared 2'-deoxy-uridine. The method has been demonstrated by the synthesis of [2',5'-(13)C(2)]- and [1',2',5'-(13)C(3)]thymidine as well as [1',2',5'-(13)C(3)]2'-deoxyuridine and [3',4'-(13)C(2)]2'-deoxycytidine. In addition the nucleoside bases thymine and uracil are tetralabeled at the (1,3-(15)N(2),2,4-(13)C(2))-atomic positions. All compounds are prepared without any scrambling or dilution of the labeled material and are thus obtained with a very high isotope enrichment (96-99%). In combination with the methods that have been developed earlier it is concluded that each of the (13)C- and (15)N-positions and combination of positions of the pyrimidine deoxynucleosides can be efficiently labeled starting from commercially available and highly (13)C- or (15)N-enriched formaldehyde, acetaldehyde, acetic acid, potassium cyanide, methylamine hydrochloride, and ammonia.

SKY1 is involved in cisplatin-induced cell kill in Saccharomyces cerevisiae, and inactivation of its human homologue, SRPK1, induces cisplatin resistance in a human ovarian carcinoma cell line

The therapeutic potential of cisplatin, one of the most active and widely used anticancer drugs, is severely limited by the occurrence of cellular resistance. In this study, using budding yeast Saccharomyces cerevisiae as a model organism to identify novel drug resistance genes, we found that disruption of the yeast gene SKY1 (serine/arginine-rich protein-specific kinase from budding yeast) by either transposon insertion or one-step gene replacement conferred cellular resistance to cisplatin. Heterologous expression of the human SKY1 homologue SRPK1 (serine/arginine-rich protein-specific kinase) in SKY1 deletion mutant yeast cells restored cisplatin sensitivity, suggesting that SRPK1 is a cisplatin sensitivity gene, the inactivation of which could lead to cisplatin resistance. Subsequently, we investigated the role of SRPK1 in cisplatin sensitivity and resistance in human ovarian carcinoma A2780 cells using antisense oligodeoxynucleotides. Treatment of A2780 cells with antisense oligodeoxynucleotides directed against the translation initiation site of SRPK1 led to down-regulation of SRPK1 protein and conferred a 4-fold resistance to cisplatin. The human SRPK1 gene has not been associated with drug resistance before. Our new findings strongly suggest that SRPK1 is involved in cisplatin-induced cell kill and indicate that SRPK1 might potentially be of importance for studying clinical drug resistance.

Possible bradycardic mode of death and successful pacemaker treatment in a large family with features of long QT syndrome type 3 and Brugada syndrome

INTRODUCTION

We recently identified a novel mutation of SCN5A (1795insD) in a large family with features of both long QT syndrome type 3 and the Brugada syndrome. The purpose of this study was to detail the clinical features and efficacy of pacemaker therapy in preventing sudden death in this family.

METHODS AND RESULTS

The study group consisted of 116 adult family members: 60 carriers (29 males) and 56 noncarriers (28 males) of the mutant gene. Investigations included 24-hour Holter monitoring, ergometry, and electrophysiologic studies. Mean, lowest, and highest heart rate were lower in the carriers, but heart rate variability was comparable. In carriers, disproportional QT prolongation was present during bradycardia. No complex ventricular ectopy was recorded, and there were fewer isolated premature beats (both ventricular and atrial) in carriers. All patients were asymptomatic, except for two individuals who experienced syncope; in one of these patients, asystolic episodes (up to 9 sec) were repeatedly recorded. Prolonged HV intervals were present in 5 of 6 patients. Thirty carriers received a prophylactic backup pacemaker. During median follow-up of 4.5 years (range 0.0 to 22.6), their survival rate was 100%. There were five sudden deaths among the remaining 30 carriers without a pacemaker (P = 0.019).

CONCLUSION

This family with a high incidence of nocturnal sudden death is characterized by bradycardia-dependent QT prolongation, intrinsic sinus node dysfunction, and generalized conduction abnormalities. There is a striking absence of complex ventricular ectopy, and pacemaker implantation was effective in preventing sudden death. These findings raise the possibility of a bradycardic rather than tachycardic mode of death.

Stress, glucocorticoids and the susceptibility to develop autoimmune disorders of the central nervous system

Alterations of the immunoendocrine circuit along the hypothalamic-pituitary-adrenocortical (HPA) axis in various autoimmune diseases have recently been observed, suggesting a modulatory role of this feedback regulation in the pathogenesis of autoimmune diseases. Susceptibility to experimental autoimmune encephalomyelitis (EAE) may be influenced by variations in the production of endogenous glucocorticoid hormones (GC). The adrenocortical response is central to recovery from EAE in the Lewis rat, as reflected by increased severity of the disease in adrenalectomized animals. The key role of GC in modifying the induction and progression of EAE is also emphasized by a reversal of corticoid-mediated effects through treatment with glucocorticoid receptor (GR) antagonists. We studied the relationship between defective GR function and susceptibility to EAE in transgenic (Tg) mice expressing GR antisense RNA. EAE was induced with the encephalitogenic myelin oligodendrocyte peptide (pMOG 36-50) in wild type (Wt) and transgenic (Tg) female mice bearing GR antisense RNA. pMOG 36-50 induced typical EAE in Wt mice but not in Tg mice. Histological examination of brains and spinal cords of Wt mice showed the presence of inflammation and/or demyelination, whereas in Tg mice neither were present. Although the mechanisms underlying the resistance of Tg mice to EAE induction are not yet clarified, compensatory changes at different levels of the HPA-immune axis in response to the potent immunogenic challenge are likely to participate in the observed effects. This work underlies the plasticity of the HPA-immune axis and suggests that pharmacological manipulation of neuroendocrine-immune networks may be a therapy of multiple sclerosis.

Dinuclear alkyldiamine platinum antitumor compounds: a structure-activity relationship study

Six related dinuclear trans-platinum complexes, with the formula [[trans-PtCl(2)(NH(3))(L)](2)(mu-H(2)N(CH(2))(n)NH(2))](2+) (L = pyridine, 2-picoline, 4-picoline; n = 4, 6) and chloride or nitrate anions, are compared with known cytotoxic dinuclear compounds (L = NH(3); n = 4, 6) that overcome cisplatin resistance. The cytotoxicity of the compounds was determined in L1210 murine leukemia and L1210/2, a cisplatin-resistant derivative. Unlike the L = NH(3) compounds, the substituted n = 4 compounds are more susceptible toward the resistance mechanisms in L1201/2. The n = 6 compounds, however, have comparable IC(50) values in both cell lines. In general, the substituted compounds are less cytotoxic than their NH(3) counterparts. After incubation with equimolar concentrations, the amount of platinum bound to cellular DNA was determined. The compounds show comparable binding, except for the sterically hindered 2-picoline compounds that bind significantly less. The amounts of platinum bound to DNA do not correlate with the cytotoxicity data. As DNA is considered to be the cellular target of platinum antitumor drugs, structural details of the DNA adducts probably account for the differences in cytotoxic activity.

Autonomic dysfunction in patients with mild heart failure and coronary artery disease and the effects of add-on beta-blockade

AIM

Autonomic impairment is related to the incidence of sudden death in chronic heart failure (CHF). Our objective was to study autonomic profiles in patients with mild CHF due to coronary artery disease, and to investigate the value of add-on beta-blockade.

METHODS AND RESULTS

Measures of autonomic function (plasma norepinephrine, heart rate [HR] variability, autonomic function testing), and exercise capacity, were compared between 24 patients with mild CHF, and 24 healthy controls. In this mechanistic study, we assessed the effect of 26 weeks metoprolol treatment in a double-blind, randomized, placebo-controlled design. All patients received metoprolol sustained release (200 mg; n=12) or placebo (n=12). Assessments were made at baseline and after 10 and 26 weeks' treatment. At baseline, norepinephrine levels were elevated, while HR variability parameters were decreased in patients vs. controls (both P<0.05). Autonomic function testing showed only small differences, although significant alterations were observed with deep breathing and head up tilting (both P<0.05). After 26 weeks', metoprolol did not affect exercise capacity or norepinephrine concentrations. In contrast, HR variability was markedly improved in metoprolol-treated patients vs. placebo-treated patients (P<0.05). In particular, a shift toward normal in the sympathovagal balance was observed (P<0.05). Autonomic function testing showed only small, and generally non-significant trends after metoprolol.

CONCLUSIONS

Marked autonomic abnormalities are already present in mild CHF, which may be (partially) reversed by metoprolol. These observations support the reported reduction of sudden death by beta-blockade in patients with CHF.

Spt4 modulates Rad26 requirement in transcription-coupled nucleotide excision repair

The nucleotide excision repair machinery can be targeted preferentially to lesions in transcribed sequences. This mode of DNA repair is referred to as transcription-coupled repair (TCR). In yeast, the Rad26 protein, which is the counterpart of the human Cockayne syndrome B protein, is implicated specifically in TCR. In a yeast strain genetically deprived of global genome repair, a deletion of RAD26 renders cells UV sensitive and displays a defect in TCR. Using a genome-wide mutagenesis approach, we found that deletion of the SPT4 gene suppresses the rad26 defect. We show that suppression by the absence of Spt4 is specific for a rad26 defect and is caused by reactivation of TCR in a Rad26-independent manner. Spt4 is involved in the regulation of transcription elongation. The absence of this regulation leads to transcription that is intrinsically competent for TCR. Our findings suggest that Rad26 acts as an elongation factor rendering transcription TCR competent and that its requirement can be modulated by Spt4.

Effect of very early angiotensin-converting enzyme inhibition on left ventricular dilation after myocardial infarction in patients receiving thrombolysis: results of a meta-analysis of 845 patients. FAMIS, CAPTIN and CATS Investigators

OBJECTIVES

We sought to investigate the effect of angiotensin-converting enzyme (ACE) inhibition <9 h after myocardial infarction (MI) on left ventricular (LV) dilation in patients receiving thrombolysis.

BACKGROUND

The ACE inhibitors reduce mortality after MI. Attenuation of LV dilation has been suggested as an important mechanism.

METHODS

The data of 845 patients with three-month echocardiographic follow-up after MI were combined from three randomized, double-blind, placebo-controlled studies. The criteria for these studies included: 1) thrombolytic therapy; 2) ACE inhibition within 6 to 9 h; and 3) evaluation of LV dilation as the primary objective.

RESULTS

The ACE inhibitor was started 3.2+/-1.7 h after the patients' first (mainly, 85%) anterior MI. After three months, LV dilation was not significantly attenuated by very early treatment with an ACE inhibitor. The diastolic volume index was attenuated by 0.5 ml/m2 (95% confidence interval [CI] -1.5 to 2.5, p = 0.61), and the systolic volume index by 0.5 ml/m2 (95% CI -1.0 to 1.9, p = 0.50). Subgroup analysis demonstrated that LV dilation was significantly attenuated by ACE inhibitor treatment for patients in whom reperfusion failed. In contrast, LV dilation was almost unaffected by ACE inhibitor treatment in successfully reperfused patients.

CONCLUSIONS

We could not demonstrate attenuation of LV dilation in patients receiving thrombolysis by ACE inhibitor treatment within 6 to 9 h after MI. We speculate that very early treatment with an ACE inhibitor has a beneficial effect on LV remodeling only in patients in whom reperfusion failed. Other mechanisms may be responsible for the beneficial effects of ACE inhibitors in successfully reperfused patients after MI.

Why are A(2B) receptors low-affinity adenosine receptors? Mutation of Asn273 to Tyr increases affinity of human A(2B) receptor for 2-(1-Hexynyl)adenosine

Adenosine A(2B) receptors are known as low-affinity receptors due to their modest-to-negligible affinity for adenosine and prototypic agonists. Despite numerous synthetic efforts, 5'-N-ethylcarboxamidoadenosine (NECA) still is the reference agonist, albeit nonselective for this receptor. In our search for higher affinity agonists, we developed decision schemes to select amino acids for mutation to the corresponding residues in the most homologous, higher affinity, human A(2A) receptor. One scheme exploited knowledge on sequence alignments and modeling data and yielded three residues, V11, L58, and F59, mutation of which did not affect agonist affinity. The second scheme combined knowledge on sequence alignments and mutation data and pointed to Ala12 and Asn273. Mutation of Ala12 to threonine did not affect the affinity for NECA, (R)-N(6)-(phenylisopropyl)adenosine (R-PIA), and 2Cl Ado. The affinity of the N273Y mutant for NECA and R-PIA and for the antagonists xanthine amine congener (XAC), ZM241385, and SCH58261 was also unaltered. However, this mutant had a slightly increased affinity for a 2-substituted adenosine derivative, CGS21680. This prompted us to investigate other 2-substituted adenosines, with selectivity and high affinity for A(2A) receptors. All four compounds tested had improved affinity for the N273Y receptor. Of these, 2-(1-hexynyl)adenosine had submicromolar affinity for the N273Y receptor, 0.18 +/- 0.10 microM, with a 61-fold affinity gain over the wt receptor. In addition, the non-NECA analog (S)-PHP adenosine had an affinity of 1.7 +/- 0.5 microM for the wt receptor. The high affinity of (S)-PHP adenosine for the wt receptor suggests that further modifications at the 2-position may yield agonists with even higher affinity for A(2B) receptors.

Cloning of a human homolog of the yeast nucleotide excision repair gene MMS19 and interaction with transcription repair factor TFIIH via the XPB and XPD helicases

Nucleotide excision repair (NER) removes UV-induced photoproducts and numerous other DNA lesions in a highly conserved 'cut-and-paste' reaction that involves approximately 25 core components. In addition, several other proteins have been identified which are dispensable for NER in vitro but have an undefined role in vivo and may act at the interface of NER and other cellular processes. An intriguing example is the Saccharomyces cerevisiae Mms19 protein that has an unknown dual function in NER and RNA polymerase II transcription. Here we report the cloning and characterization of a human homolog, designated hMMS19, that encodes a 1030 amino acid protein with 26% identity and 51% similarity to S.cerevisiae Mms19p and with a strikingly similar size. The expression profile and nuclear location are consistent with a repair function. Co-immunoprecipitation experiments revealed that hMMS19 directly interacts with the XPB and XPD subunits of NER-transcription factor TFIIH. These findings extend the conservation of the NER apparatus and the link between NER and basal transcription and suggest that hMMS19 exerts its function in repair and transcription by interacting with the XPB and XPD helicases.

Cardiac abnormalities in SLE: pancarditis

Many patients with systemic lupus erythematosus (SLE) develop cardiac manifestations during the course of their disease. Pericarditis is most commonly seen, with a reported prevalence of 60%. Myocardial involvement is present in only a minority of patients. In recent years, due to better noninvasive diagnostic techniques, valvular abnormalities can be demonstrated in an increasing number of patients. Depending on the technique used, valvulopathy can be demonstrated in up to 77% of SLE patients. Although most of the valvular lesions will be present without any symptoms, valve incompetence can result in congestive heart failure. Valvular lesions are associated with IgG anticardiolipin antibodies (aCL) and disease duration. We present a patient with SLE and secondary antiphospholipid syndrome (APS) who developed acute congestive heart failure due to pancarditis. Endocarditis, together with left ventricular dysfunction and pericardial effusion, were present. The endocarditis caused hemodynamically significant mitral valve insufficiency due to thickening of the mitral cusps. Just two weeks prior to the occurrence of congestive heart failure echocardiography had been normal. Treatment with high dose corticosteroids resulted in a gradual, almost complete recovery. Literature concerning cardiac manifestations in lupus is reviewed.

Effect of mibefradil on heart rate variability in patients with chronic heart failure

BACKGROUND

Mibefradil was recently withdrawn from the market because of an unfavorable clinical profile in patients with chronic heart failure. Although drug interactions appear to play a role, other mechanisms such as proarrhythmia and autonomic deterioration could also be relevant. Chronic heart failure is accompanied by autonomic impairment and analysis of heart rate variability can be used to examine autonomic modulation of heart rate.

METHODS

We studied 18 heart failure patients (age 63.2+/-10.1 years (mean+/-S.D. ), ejection fraction 0.21+/-0.07) treated with mibefradil or placebo, who participated in the MACH-I (Mortality Assessment in Chronic Heart failure) trial in our center, and compared them with 18 healthy matched controls. Heart rate variability analysis was performed at baseline and after 7 months of treatment.

RESULTS

At baseline, heart rate variability parameters were impaired in patients with heart failure compared to healthy controls (P<0.05). After 7 months of treatment a reduction in (24-h) heart rate was observed (P=0.02, versus placebo). Apart from the effect on mean NN, no significant differences were observed for the remaining heart rate variability parameters.

CONCLUSIONS

Mibefradil does not impair autonomic balance and in fact reduces heart rate in patients with heart failure. These findings suggest that autonomic activation did not contribute to the adverse effects of mibefradil.

A genome-wide screening in Saccharomyces cerevisiae for genes that confer resistance to the anticancer agent cisplatin

Cisplatin is a potent DNA-damaging agent that has demonstrated anticancer activities against several tumors. However, manifestation of cellular resistance is a major obstacle in anticancer therapy that severely limits the curative potential of cisplatin. Therefore, understanding the molecular basis of cisplatin resistance could significantly improve the clinical efficacy of this anticancer agent. Here, we employed Saccharomyces cerevisiae as a model organism to study cisplatin resistance mechanisms and describe a one-step cisplatin selection to identify and characterize novel cisplatin resistance genes. Screening a multicopy yeast genomic library enabled us to isolate several yeast clones for which we could confirm that the cisplatin resistance phenotype was linked to the introduced fragment. In a first attempt, a number of open reading frames could be identified. Among these genes, PDE2 and ZDS2 were repeatedly identified as genes whose overexpression confers cellular resistance to cisplatin. PDE2, encoding cAMP-phosphodiesterase 2, is of particular interest because the overexpression of this yeast gene is known to induce cisplatin resistance in mammalian cells as well, providing proof of the principle of our experimental approach. In addition, the identification of PDE2 shows that our yeast screening system can directly be informative for drug resistance in mammalian cells.

Identification and characterization of the rhp23(+) DNA repair gene in Schizosaccharomyces pombe

We have identified rhp23(+), the ortholog of the Saccharomyces cerevisiae RAD23 and human HHR23A and HHR23B genes, in Schizosaccharomyces pombe and examined its role in cell survival and DNA repair. In S. pombe two repair mechanisms are operative on UV-induced photoproducts, i.e., UV damage repair (UVDR) and nucleotide excision repair (NER). Here we show that Rhp23 is solely involved in NER and study its role in DNA repair in the absence of the UVDR pathway. S. pombe rhp23-deficient cells are sensitive toward UV irradiation, although not as sensitive as complete NER-deficient cells. Furthermore we demonstrate that the residual survival observed in rhp23-deficient cells is NER dependent. Despite this NER-dependent survival, uvde rhp23 double mutants are unable to repair cyclobutane pyrimidine dimers. The inability to remove these photolesions from both DNA strands clearly demonstrates that rhp23(+) is involved in transcription coupled repair as well as global genome repair.

Tachycardia induced electrical remodeling of the atria and the autonomic nervous system in goats

Atrial fibrillation (AF) shortens the atrial effective refractory period (AERP). To investigate the role of the autonomic nervous system during this so-called electrical remodeling of the atria (ERA) and during recovery from ERA we analyzed heart rate variability (HRV). In 12 goats atrioventricular (300:150 beats/min) pacing was performed for 24 hours, interrupted at 4, 8, 16, and 24 hours for recording of 500 atrial (AA) intervals during sinus rhythm and measurement of the AERP(430ms) at 7.4 +/- 0.6 sites. After 24 hours, pacing was stopped and the electrophysiological study and recording of the AA intervals was repeated at 4, 8, 16, and 24 hours after cessation of pacing. Time- and frequency-domain parameters were computed from each 500 AA interval recording. After 24 hours of rapid pacing the AERP had shortened significantly (147 +/- 5.6 to 102+/- 6.4 ms, P < 0.0001). No significant changes in HRV and dispersion of refractoriness (AAERP) (47 +/- 7.1 to 44 +/- 4.2 ms) were observed. After cessation of pacing, the AERP prolonged again (102 +/-6.4 to 135+/-8.8 ms, P < 0.0001) and was paralleled by a significant increase in AAERP (44 +/- 4.2 to 63+/- 7.1 ms, P = 0.01). Furthermore, HRV increased significantly. At each time point an inverse relation between the logarithmically transformed vagal parameter HF (InHF) and AERP was observed. We calculated the mean InHF for each goat using all time points and used the median value to divide the 12 goats into high and low vagal tone groups. We compared the degree of ERA and recovery from ERA for both groups. The AERP shortened 47.4 +/- 6.5 versus 43.0+/-5.0 ms (NS) for goats with high and low vagal tone, respectively. During recovery from ERA the AERP lengthened 23.6 +/- 4.0 versus 42.5 +/- 1.7 ms (P = 0.001) for goats with high and low vagal tone, respectively. Multivariate regression analysis indicated a short AERP as the single independent determinant of the inducibility of AF during ERA and recovery from ERA (P < 0.0001). During recovery from ERA, the AERP prolonged and vagal tone and AAERP increased. A high vagal tone during recovery from ERA was associated with a short AERP and an attenuated recovery of ERA.

Clinical follow-up after cessation of chronic electrical neuromodulation in patients with severe coronary artery disease: a prospective randomized controlled study on putative involvement of sympathetic activity

The present study assessed the reoccurrence of myocardial ischemia after withholding electrical neurostimulation. After randomization, in the study or withdrawal group, spinal cord stimulation (SCS) was set active during the first 4 weeks, followed by 4 weeks of withholding stimulation. In the control group, SCS was switched off during 4 weeks before the end of the study. The control group had no crossover period. Measurements were done at baseline, then after 4 and 8 weeks. The first periods at 4 weeks of each sequence of both groups were compared. In addition, a comparison of clinical variables was performed between the study group 4 weeks after withholding stimulation and the control group 4 weeks following randomization. A total number of 24 patients with refractory angina and an implanted spinal cord stimulator were included in the study (n = 12) and control group. Angina pectoris complaints, nitroglycerin intake, ischemia, and heart rate variability using 48-hour ambulatory electrocardiographic monitoring were assessed. In addition, neurohormonal status and symptom-limited aerobic capacity were evaluated. There was no increase of anginal complaints or ischemia after withholding stimulation. Neurohormonal levels and aerobic capacity were not altered. We conclude that there is no adverse clinical rebound phenomenon after withholding neurostimulation in patients with refractory angina pectoris.

Characterization of the rhp7(+) and rhp16(+) genes in Schizosaccharomyces pombe

The global genome repair (GGR) subpathway of nucleotide excision repair (NER) is capable of removing lesions throughout the genome. In Saccharomyces cerevisiae the RAD7 and RAD16 genes are essential for GGR. Here we identify rhp7 (+), the RAD7 homolog in Schizosaccharomyces pombe. Surprisingly, rhp7 (+)and the previously cloned rhp16 (+)are located very close together and are transcribed in opposite directions. Upon UV irradiation both genes are induced, reaching a maximum level after 45-60 min. These observations suggest that the genes are co-regulated. Schizo-saccharomyces pombe rhp7 or rhp16 deficient cells are, in contrast to S.cerevisiae rad7 and rad16 mutants, not sensitive to UV irradiation. In S.pombe an alternative repair mechanism, UV damage repair (UVDR), is capable of efficiently removing photolesions from DNA. In the absence of this UVDR pathway both rhp7 and rhp16 deficient cells display an enhanced UV sensitivity. Epistatic analyses show that rhp7 (+)and rhp16 (+)are only involved in NER. Repair analyses at nucleotide resolution demonstrate that both Rhp7 and Rhp16, probably acting in a complex, are essential for GGR in S.pombe.

Removal of cyclobutane pyrimidine dimers by the UV damage repair and nucleotide excision repair pathways of Schizosaccharomyces pombe at nucleotide resolution

In Schizosaccharomyces pombe two different repair mechanisms remove UV-induced lesions from DNA, i.e. nucleotide excision repair (NER) and UV damage repair (UVDR). Here, the kinetics of removal of cyclobutane pyrimidine dimers (CPDs) by both pathways is determined at base resolution in the transcribed strand (TS) and the non-transcribed strand (NTS) of the sprpb2 +gene. UVDR does not remove lesions in a strand-specific manner, indicating that UVDR is neither stimulated nor inhibited by RNA polymerase II transcription. In contrast, in a UVDR-deficient strain the TS is repaired preferentially. This strong strand bias suggests that in S.pombe, as in other species, NER is coupled to transcription. In repair-proficient S.pombe the TS is repaired very rapidly, as a consequence of two efficiently operating pathways, while the NTS is repaired more slowly, mainly by UVDR. Furthermore, we demonstrate that UVDR is not always faster than NER.

Different effects of bisoprolol on heart rate in patients with ischemic or idiopathic dilated cardiomyopathy (a 24-hour Holter substudy of the Cardiac Insufficiency Bisoprolol Study [CIBIS])

The effect of beta blockade on heart rate in patients with either idiopathic or ischemic cardiomyopathy was studied. It was found that beta blockade reduced the early morning increase in heart rate to a greater extent in patients with idiopathic dilated cardiomyopathy than in those with ischemic dilated cardiomyopathy.

Rad26, the yeast homolog of the cockayne syndrome B gene product, counteracts inhibition of DNA repair due to RNA polymerase II transcription

Transcription-coupled DNA repair (TCR) is responsible for the preferential removal of DNA lesions from the transcribed strands of RNA polymerase II transcribed genes. Saccharomyces cerevisiae rad26 mutants and cells from patients suffering from the hereditary disease Cockayne syndrome display a TCR defective phenotype. Whether this lack of preferential repair has to be explained by a defect in repair or in general transcription is unclear at present. To discriminate between both possibilities, we analyzed repair of UV-induced cyclobutane pyrimidine dimers at single base resolution in yeast cells lacking RAD26, the homolog of the Cockayne syndrome B gene. Disrupting RAD26 affects nucleotide excision repair of transcribed DNA irrespective of the chromatin context, resulting in similar rates of removal for individual cyclobutane pyrimidine dimers throughout the transcribed strand. Notably, repair of transcribed sequences in between core nucleosomal regions is less efficient compared with nontranscribed DNA at these positions, pointing to a nucleotide excision repair impediment caused by blocked RNA polymerase. Our in vivo data demonstrate that the TCR defect in rad26 mutant cells is not due to a general transcription deficiency but results from the inability to release the transcription complex trapped at sites of base damage.

RNA polymerase II transcription suppresses nucleosomal modulation of UV-induced (6-4) photoproduct and cyclobutane pyrimidine dimer repair in yeast

The nucleotide excision repair (NER) pathway is able to remove a wide variety of structurally unrelated lesions from DNA. NER operates throughout the genome, but the efficiencies of lesion removal are not the same for different genomic regions. Even within a single gene or DNA strand repair rates vary, and this intragenic heterogeneity is of considerable interest with respect to the mutagenic potential of carcinogens. In this study, we have analyzed the removal of the two major types of genotoxic DNA adducts induced by UV light, i.e., the pyrimidine (6-4)-pyrimidone photoproduct (6-4PP) and the cyclobutane pyrimidine dimer (CPD), from the Saccharomyces cerevisiae URA3 gene at nucleotide resolution. In contrast to the fast and uniform removal of CPDs from the transcribed strand, removal of lesions from the nontranscribed strand is generally less efficient and is modulated by the chromatin environment of the damage. Removal of 6-4PPs from nontranscribed sequences is also profoundly influenced by positioned nucleosomes, but this type of lesion is repaired at a much higher rate. Still, the transcribed strand is repaired preferentially, indicating that, as in the removal of CPDs, transcription-coupled repair predominates in the removal of 6-4PPs from transcribed DNA. The hypothesis that transcription machinery operates as the rate-determining damage recognition entity in transcription-coupled repair is supported by the observation that this pathway removes both types of UV photoproducts at equal rates without being profoundly influenced by the sequence or chromatin context.

Defective Kin28, a subunit of yeast TFIIH, impairs transcription-coupled but not global genome nucleotide excision repair

The essential Saccharomyces cerevisiae KIN28 gene encodes a subunit of general transcription factor TFIIH, a multiprotein complex required for RNA polymerase II transcription initiation and nucleotide excision repair (NER). Kin28 is implicated in the transition from transcription initiation to transcription elongation by phosphorylation of the carboxy-terminal domain (CTD) of the largest subunit of the RNA polymerase II complex. Here, we explore the possibility that Kin28 like the other subunits of TFIIH is involved in NER in vivo, using yeast cells carrying either a wildtype or a thermosensitive KIN28 allele. The removal of UV induced cyclobutane pyrimidine dimers (CPDs) was monitored at base resolution from both strands of the RNA polymerase II transcribed genes RPB2 and URA3. Cells carrying the thermosensitive KIN28 allele display a transcription-coupled repair (TCR) defect at the non-permissive temperature, which was most pronounced directly downstream of transcription initiation, probably as an indirect result of a general decrease in the level of RNA polymerase II transcription. The fact that CPD removal in non-transcribed DNA is completely unaffected in these cells indicates that Kin28 is not essential for general NER in vivo, providing the first example of a TFIIH subunit that is required for TCR but not for NER in general.

Preferential binding of yeast Rad4.Rad23 complex to damaged DNA

The yeast Rad4 and Rad23 proteins form a complex that is involved in nucleotide excision repair (NER). Their function in this process is not known yet, but genetic data suggest that they act in an early step in NER. We have purified an epitope-tagged Rad4.Rad23 (tRad4. Rad23) complex from yeast cells, using a clone overproducing Rad4 with a hemagglutinin-tag at its C terminus. tRad4.Rad23 complex purified by both conventional and immuno-affinity chromatography complements the in vitro repair defect of rad4 and rad23 mutant extracts, demonstrating that these proteins are functional in NER. Using electrophoretic mobility shift assays, we show preferential binding of the tRad4.Rad23 complex to damaged DNA in vitro. UV-irradiated, as well as N-acetoxy-2-(acetylamino)fluorene-treated DNA, is efficiently bound by the protein complex. These data suggest that Rad4.Rad23 interacts with DNA damage during NER and may play a role in recognition of the damage.

Reactive oxygen species are required for the phagocytosis of myelin by macrophages

Reactive oxygen species (ROS) are thought to be involved in the pathogenesis of multiple sclerosis (MS) and experimental allergic encephalomyelitis (EAE). In this study we showed that the phagocytosis of myelin by macrophages triggers the production of ROS. We also demonstrated that ROS play a crucial role in the myelin phagocytosis. Blocking the ROS production with NADPH oxidase inhibitors (100 microM DPI or 10 mM Apocynin) essentially prevented the phagocytosis of myelin. Furthermore, scavenging of ROS with catalase (H2O2) or mannitol (OH-) decreased the phagocytosis of myelin by macrophages, whereas superoxide dismutase (O2-) did not show this effect. In addition, Lipoic acid (LA), a non-specific scavenger of ROS, also decreased the phagocytosis of myelin by macrophages. In our results, we demonstrate for the first time that ROS appear to play a regulatory role in the phagocytosis of myelin.