Effectiveness and safety of bipolar ablation of heart arrhythmia. A systematic review with meta-analysis

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The National Centre for Research and Development, Poland

Introduction

Bipolar radiofrequency ablation (BFRA) emerged as a viable technique of radiofrequency ablation where the standard unipolar approach (RFA) failed. A number of studies describing BRFA were published recently suggesting high effectiveness and acceptable safety of this technology for ablation of ventricular tachycardia in structural heart disease (SHD VT), premature ventricular contractions (PVC) or atrial flutter (AFL).

Purpose

We performed a systematic review with meta-analysis of available evidence to assess contemporary evidence on the effectiveness and safety of bipolar ablation of heart arrhythmia.

Methods

We systematically searched MEDLINE, EMBASE, and CENTRAL databases from inception to 27 August 2022 for prospective and retrospective studies with or without a control group. We also contacted BRFA experts to obtain information on the most up-to-date studies or conference presentations. Case studies and papers describing technical aspects of BRFA rather than clinical outcomes were excluded. Study quality was assessed using the Newcastle–Ottawa Scale.

Results

Out of 1919 records we included 12 studies: one good quality case-control study and 11 low-quality case series without a control group. Studies described 120 patients who received BFRA: mean age 61.9±10.3 years, 81% males, mean ejection fraction 43.2±12.4, SHD 62.6%, ICD/CRT-D 52.2%. Almost all patients were qualified to BRFA due to failure of at least one unipolar RFA. Follow-up period differed between studies and ranged between 1-2 years in most cases.

The overall acute effectiveness of BRFA was 88.2% (95%CI 82.5-93.8), I2=6.7%. The overall effectiveness of a first BRFA at the end of the follow-up period was 55% (95%CI 46.2-63.7), I2=7.2%. There was a need for a re-ablation in 21.2% patients (95%CI 11.2-31.2), I2=64%. A subgroup analysis for SHD VT, PVC and AFL yielded similar results. There were 16 serious complications including one surgical intervention and no acute deaths; five patients died during the follow-up, mainly due to heart failure progression.

Conclusions

Bipolar radiofrequency ablation may be an effective and safe procedure in selected patients who failed at least one unipolar radiofrequency ablation but the quality of the supporting evidence is generally low.

Dubious effect of the high biventricular paced beats percentage itself on the cardiac resynchronization efficacy in patients with atrial fibrillation. The randomized Pilot-CRAfT Study results

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Institute of Cardiology statutory grant

Background

The presence of atrial fibrillation (AF) in cardiac resynchronization therapy (CRT) recipients is common and AF is a marker of poorer CRT response. The negative influence of AF on CRT efficacy is belived to be mediated mainly by the drop of effectively captured biventricular paced beats percentage (BiVp%). According to observational trials, the minimal BiVp associated with better outcomes is 95-98%, however there is lack of randomized trials to confirm this findings.

Purpose

The purpose of the study was to assess the influence of BiVp% itself on the clinical outcomes in the population CRT patients with atrial fibrillation in a prospective, randomized cohort.

Methods

The study included the prospective Pilot-CRAfT study participants that is patients with CRT and permanent or persistent AF lasting for ≥6 months that were randomly assigned to rhythm or rate control strategy. We divided the whole study population according to their BiVp at the 12 month follow-up with two borderline BiVp values (BiVp >98% vs <98% and >95% vs <95%) and analysed the echocardiographic indices, exercise tolerance and quality of life between the prespecified groups.

Results

The study included 43 CRT patients (97,7% males) aged 68,4 (SD: ±8,3) years with mean BiVp% 82,4% ±9,7% at baseline. The mean baseline left ventricular ejection fraction (LVEF), left ventricular end diastolic diameter (LVEDD) and maximal oxygen uptake (VO2max) were: 30 ±8%, 65 ±8 mm, 14 ±5 mL/(kg*min), respectively. In both of the study arms the BiVp% raised significantly reaching 98,1 ±2,3% and 96,3 ±3,9% in the rhythm control and the rate control arms respectively (P=0,093). As a result the were overall 21 patients with BiVp >98% and 29 patients with BiVp >95% at the end of the study. The BiVp groups >98% vs <98% and >95% vs <95% did not differ as to baseline characteristics and we have not observed any differences in the mean LVEF, mean LVEDD, mean VO2max, and quality of life in the prespecified BiVp% groups at the end of the follow up. Moreover no linear correlations between the BiVp% and LVEF, LVEDD, VO2max values were observed. However, in the rate control group patients with AVNA performed had lower LVEDD at the end of the study (57,7 ±3,0 vs 65,4 ±7,0 p=0,007) and significant decrease in the LVEDD after AVNA was observed (-8,6 95%CI [-14,9; -2,3]).

Conclusions

The BiVp >98% or >95% alone does not seem to warrant good response to cardiac resynchronization in patients with persistent atrial fibrillation as assessed in the prospective randomized cohort. However, performing AVNA in this group of patients may be beneficial in terms of LVEDD decrease.

Pharmacological cardioversion of recent-onset atrial fibrillation in patients with chronic kidney disease: sub-analysis of the CANT study

Purpose

Pharmacological cardioversion (PCV) is commonly a primary option for termination of recent-onset atrial fibrillation (AF) at the emergency departments (ED), and there are reports proving that antazoline is a noteworthy agent to restore sinus rhythm. This is a sub-analysis of the CANT study evaluating the effectiveness and safety of antazoline in patients with AF at different stages of chronic kidney disease (CKD).

Methods

Total n=777 patients admitted to ED for the urgent termination of AF were included into this analysis. We analysed the results concerning effectiveness and safety of PCV with special consideration of antazoline, in patients at 3 stages of CKD defined on the basis of eGFR (CKD-EPI): Group I ≥60 mL/min (n=531), Group II 45–59 mL/min (n=149), and Group III <45 mL/min (n=97). Primary end-point was the termination of AF, a restoration of a sinus rhythm and its persistence until discharge.

Results

Patients of group III were older and with higher prevalence of comorbidities, however, we have not found statistically significant differences in overall effectiveness of PCV in comparison with the other groups. In patients receiving amiodarone, the PCV success rate was similar in all the studied groups, but along with a renal function decline, it decreased in patients receiving antazoline (79.1 vs 35%; p<0.001), and it increased close to a significant manner in patients receiving propafenone (69.9 vs 100%; p=0.067; Figure). In patients of Group I, antazoline restored a sinus rhythm as effectively as propafenone and amiodarone, however in patients of Group III, both antazoline and amiodarone became less effective in restoring a sinus rhythm than propafenone (p=0.002 and p=0.034, respectively). The rate of safety endpoint was highest in patients of Group III (eGFR<45 mL/min), and it was significantly higher than in patients of Group I and II (p=0.008 and p=0.036, respectively). We have not observed antazoline-related adverse events in any of studied groups of patients.

Conclusion

This real-world registry analysis revealed a different influence of CKD on individual drug effectiveness, and while propafenone and amiodarone maintained their AF termination efficacy, antazoline became significantly less effective in restoring sinus rhythm. Its favourable safety profile has not changed.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): The study received no external funding

Rhythm or rate control strategy in CRT recipients with long-standing persistent atrial fibrillation - preliminary results of the PilotCRAfT study

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): National Institute of Cardiology in Warsaw Statutory Grant

Background

The presence of atrial fibrillation (AF) in cardiac resynchronization therapy (CRT) recipients is common and AF is a marker of poorer CRT response. The negative influence of AF on CRT efficacy is mediated mainly by the drop of the effectively captured biventricular paced beats percentage (BiVp%) which should exceed 95-98% to warrant good CRT response.  Sinus rhythm (SR) restoration may improve CRT efficacy which in turn may protect AF recurrence. However, there is lack of randomized studies comparing rhythm and rate control strategies in these patients.

Purpose

The purpose of the Pilot-CRAfT study (NCT01850277) was to compare the efficacy of rhythm vs rate control strategy in CRT patients with long-standing persistent or permanent atrial fibrillation.

Methods

The study included patients with CRT and permanent or persistent AF lasting for ≥6 months, resulting in BiVp% <95%, who were randomly assigned to rhythm or rate control strategy. The rhythm control strategy comprised of external electrical cardioversion (EEC). The rate control strategy included pharmacotherapy and atrioventricular node ablation (AVNA) as needed. Both of the study arms received amiodarone. The follow-up lasted 12 months. The primary endpoint was the 12-month BiVp%. The patients underwent ECHO, cardiopulmonary test, quality of live (QoL) and clinical outcomes assessment.  

Results

The study included 43 CRT patients (97,7% males) aged 68,4 (SD: ±8,3) years with mean BiVp% 82,4% ±9,7% at baseline. The mean duration of AF paroxysm was 25 ±19 months. The mean baseline left ventricular ejection fraction (LVEF), left atrium area and maximal oxygen uptake (VO2max) were: 30 ±8%, 33 ±7 cm2, 14 ±5 mL/(kg*min), respectively. The EEC was performed in 19 out of 22 patients assigned to the rhythm control arm. The immediate success rate of EEC was 58%. 42% of  the rhythm control arm patients remained in SR after 12 months. In the rate control group 1 person underwent AVNA and in 1 patient spontaneous SR resumption was observed. After 12 months there was significant BiVp% increase in both the rhythm and the rate control arms (98,1 ±2,3 vs 96,3 ±3,9%, respectively. The BiVp% differences between the groups were not significant (P = 0,093). However, in the per protocol analysis, the rhythm control group had greater LVEF after 12 months as opposed to the rate control arm (36,8% vs 29,9% respectively, P = 0,039). The LVEF raised significantly in the rhythm control group (ΔLVEF 5,0 (95%CI: 1,54; 8,46)). No significant differences between the groups in the VO2max, QoL, clinical and safety end-points were noticed.

Conclusions

Structured follow-up of CRT patients with long-standing persistent or permanent AF leads to significant BiVp% increase exceeding 95%. The rate control strategy did not improve CRT effectivness, irrespective of high BiVp%. However limited in the efficacy, the rhythm control strategy may improve CRT outcome in these patients, resulting in LVEF increase.

Rescue of cardiac function in obese type-2 diabetic mice by transfer of a human longevity gene

Background

Healthy longevity is the result of the interaction between favourable environment and unique genetic makeup. We showed that horizontal transfer of a longevity-associated gene variant (LAV-BPIFB4) improves endothelial function and accelerates the recovery from ischemia.

Purpose

To determine if the benefit of LAV-BPIFB4 gene therapy can be extended to diabetic cardiomyopathy.

Methods and results

We confirmed that human diabetic patients with heart failure (n=13) show a decreased cardiac expression of BPIFB4 compared with healthy subjects (n=10). Obese db/db mice received a systemic injection of adeno-associated viral vector (AAV9)-LAV-BPIFB4, AAV9-wild type (WT)-BPIFB4 (both 100 μL at 1×1012 GC/mL) or vehicle before the onset of cardiomyopathy, and were euthanised four weeks later for histological, metabolic and transcriptional analyses. Echocardiographic evaluation (n=8/group), performed at baseline and after gene therapy, showed that LAV-BPIFB4 treatment, despite not resolving hyperglycaemia, improved left ventricular function compared with the other groups. Histological analyses of the hearts (n=5 to 10/group) revealed that LAV-BPIFB4 reduced myocardial fibrosis and increased angiogenesis compared with vehicle and WT-hearts; moreover, LAV increased the expression of the alpha-isoform of the cardiac myosin heavy chain, which is associated with a superior cardiomyocyte contractility. Interestingly, LAV-BPIFB4 treatment induced an increase in cardiac SDF1 expression compared with WT and vehicle, despite the mechanism linking the two events is still unknown. The oral administration of the CXCR4 antagonist AMD-070, given at 2 mg/kg/day for four weeks, abolished several of the beneficial effects exerted by the LAV-BPIFB4 therapy in the obese diabetic mice, as assessed by echocardiography and histology (n=7/group).

At the molecular level, next-generation RNA sequencing (n=3 to 4 /group) showed 8 genes were differentially expressed by LAV-BPIFB4-hearts compared with vehicle-hearts. These genes are associated with mitochondrial and metabolic functions. Among them, changes in the UCP3, HMGCS2, CS, ATPB and TOMM20 expression were also validated at the protein level by western blotting. Lipidomics using ultrahigh-performance liquid chromatography-mass spectrometry (n=6 or 7/group) showed 63 metabolites differentially expressed by LAV-BPIFB4- compared with vehicle-hearts, with only 3 (two cardiolipins and one glycerophospholipid) returning close to the non-diabetic phenotype following LAV-BPIFB4 treatment.

Conclusions

This study newly shows the possibility of transferring the benefit of salutary polymorphic gene variants to protect the cardiovascular system from metabolic pressure. Rather than combating pathogenic mechanisms, the strategy activates alternative pathways overriding disease risk factors.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): British Heart Foundation project grant “Longevity-associated BPIFB4 gene therapy for treatment of ischemic disease”

P429The efficacy of electrical cardioversion of long-standing persistent or permanent atrial fibrillation in cardiac resynchronization therapy recipients

Funding Acknowledgements

Institute of Cardiology statutory grant (grant no.: 2.30/VII/13)

Background

Atrial fibrillation (AF) and heart failure (HF) often co-exist and influence each other. The presence of AF is often regarded as a marker of HF severity.  Moreover, AF in cardiac resynchronization therapy (CRT) recipients hinders the CRT effectiveness in HF treatment by the reduction of the percentage of biventricular paced beats (BiVp%). Sinus rhythm (SR) restoration makes CRT more effective in HF treatment which may protect AF recurrence.

Purpose

To establish the effectiveness of electrical external cardioversion (EEC) in CRT patients with long-standing persistent AF or permanent, pre-treated with amiodarone.

Methods

The population of the study comprised of the Pilot-CRAfT study participants (NCT01850277), that is patients with CRT, long-standing persistent or considered as permanent AF and BiVp ≤ 95% who were randomly assigned to the "rhythm control" or the "rate control" strategy. The inclusion criteria included an AF paroxysm lasting at least 6 months. Both treatment arms received amiodarone beginning with the loading dose. Subsequently, patients assigned to the rhythm control strategy underwent electrical cardioversion. Rate control strategy included pharmacotherapy and atrioventricular node ablation, as needed. The follow up visit was performed 3 months after the enrolment visit. The EEC effectiveness, an AF recurrence within the 3 month period, BiVp% changes, the EEC parameters  and the EEC related complications were analysed.

Results

Out of 48 participants enrolled in the Pilot-CRAfT study, 25 patients were assigned to the rhythm control arm. The mean age of the rhythm control arm patients was 69,5 years , the mean left ventricular ejection fraction was 30,6% , the mean left atrium diameter was 53 mm and the median duration of persistent AF was 16 months. SR was obtained in 12 out of 20 (60%) patients who underwent the EEC . On the 3 month visit 8 patients remained in SR (40%). In patients with an AF paroxysm lasting less than 1 year the success rate was 100% vs 50% in the AF lasting 1 year at least (p = 0,11 ). After 3 months, SR remained in 100% vs 25% of patients, respectively (p =0,015.).  The effectiveness of anterior-posterior EEC electrodes placement was 20% and it was 71% for the anterior-lateral patch location . The EEC resulted in significant BiVp% rise - also in the whole intention-to-treat (ITT) group:  88,58%  before the EEC vs 96,68% after the EEC  (p = 0,002). No severe adverse events of the EEC were observed.

Conclusions

The electrical cardioversion of persistent atrial fibrillation lasting more than 6 months in patients with severe HF and treated with CRT is characterised by modest success rate, even after the amiodarone pre-treatment. However, the ECC ensures significant rise in BiVp% close to 97%, even in the whole EEC group based on the ITT principle. The AF paroxysm duration <1 year and the anterior-posterior patch placement may ensure better EEC efficacy in this group of patients.

P990Assessment of clinical risk factors for all-cause mortality among hypertrophic cardiomyopathy patients with ICDs

Introduction

According to the literature, the annual mortality rate of hypertrophic cardiomyopathy (HCM) patients is estimated to 1–2%. Sudden cardiac death (SCD), heart failure and thromboembolism are the main causes of death among this population. Patients at high risk for SCD, identified using HCM risk score, are qualified for ICD implantation. Unfortunately for clinicians, there is no validated model or statistical tool for assessment of the risk of mortality within the HCM patients with ICDs.

Purpose

The aim of this study was to determine the main risk factors of all- cause mortality in HCM patients with ICDs.

Methods

The long-term follow-up of group of 104 consecutive patients with HCM, who had the ICD implanted between 1996 and 2006 in tertiary reference clinical unit was performed. Twenty patients who died during observation were the subject of the current analysis. ICD was implanted for primary (n=16) and secondary (n=4) prevention of SCD within this subpopulation. Analysis were performed for mentioned below potential risk factors: age at the time of implantation, syncopes, family history of SCD, atrial fibrillation/supraventricular tachycardia, decreased left ventricular ejection fraction (LVEF), non-sustained ventricular tachycardia (nsVT), maximum left ventricular wall thickness, abnormal exercise blood pressure response, left ventricular outflow tract obstruction.

Results

The average time of survival since ICD implantation was 8,5±4,6 years. Decreased LVEF (Wald chi2 4,57; p=0,033), secondary prevention (Wald chi2 8,57; p=0,003), family history of SCD (Wald chi2 4,93; p=0,026) and episodes of nsVT (Wald chi2 3,49; p=0,062) are the clinical risk factors that significantly affect the time of survival. The probability of death, expressed as Hazard Ratio, was 27-fold higher in secondary prevention group (HR=27,18), almost 10-fold higher in patients with positive family history of SCD (HR=9,74) and 3,7-fold higher when nsVT was detected. The cause of death was established in 16/20 patients. In 15 cases, these were deaths from cardiovascular causes: end-stage heart failure (8), complications of heart transplantation or circulatory support (4), SCD (1) and other cardiovascular (2).

Conclusion

Secondary prevention, positive family history of SCD, nsVT and decreased LVEF seem to be the most significant risk factors associated with all- cause mortality in HCM patients with ICDs. Despite the ICD implantation, subpopulation studied had poor prognosis with high incidence of progression to end-stage heart failure. Further studies to create validated model for assessment of death risk in long-term observation of patients with HCM after ICD implantation are required.

Improved robust T-wave alternans detectors

New statistical and spectral detectors, the modified matched pairs t test, the extended spectral method and the modified spectral method, were proposed for T-wave alternans (TWA) detection gaining robustness according to trend and single-frequency interferences. They were compared to classic detectors such as matched pairs t test, unpaired t test, spectral method, generalized likelihood ratio test and estimated TWA amplitude within a simulation framework and applied to real data. The optimal detection threshold was selected by using a full Monte-Carlo simulation where signals, with and without alternans episodes, were corrupted by Gaussian noise with different power and single-frequency interferences with different tones. All the combinations of noise and frequency were selected and repeated 500 times in order to compute probability of detection ([Formula: see text]) and the false alarm probability ([Formula: see text]), providing ROC curves. The study group consisted of 50 patients with implantable cardioverter-defibrillator (age: [Formula: see text]; LVEF: [Formula: see text]), who were paced (ventricular pacing) at 100 bpm. Two-minute recordings were analyzed. The XYZ orthogonal lead system was used. The best performance was reached by using the modified matched pairs t test (in comparison with the spectral method and other reference methods).

Mechanisms of arsenic-induced cross-tolerance to nickel cytotoxicity, genotoxicity, and apoptosis in rat liver epithelial cells

The purpose of the present study was to investigate the mechanism of cross-tolerance to nickel in arsenic-transformed cells. Chronic arsenite-exposed (CAsE) cells (TRL 1215 cells, which had been continuously exposed to 0.5 microM arsenite for 20 or more weeks) and control TRL 1215 cells were both exposed to nickel for 24 h, and cell viability was determined by metabolic integrity. The LC(50) for nickel was 608 +/- 32 microM in CAsE cells as compared to 232 +/- 16 microM in control cells, a 2.6-fold increase. CAsE and control cells were treated with 200 microM nickel for 4 h and cellular-free radical production was measured using ESR spectrometry. Hydroxyl radical generation was decreased in CAsE cells. Thiobarbituric acid reactive substances, indicative of lipid peroxidation, and 8-oxo-2'-deoxyguanosine, indicative of oxidative DNA damage, were reduced in CAsE cells. Flow cytometric analysis using Annexin/FITC revealed that nickel-induced apoptosis was reduced in CAsE cells. CAsE cells showed generalized resistance to oxidant-induced toxicity as evidenced by a marked reduction in sensitivity to hydrogen peroxide. Interestingly, intracellular reduced glutathione (GSH) levels were significantly increased in CAsE cells, and when GSH was depleted, CAsE cells lost their nickel resistance. The mechanism of arsenic-induced cross-tolerance to cytotoxicity, genotoxicity, and apoptosis induced by nickel appears related to a generalized resistance to oxidant-induced injury, probably based, at least in part, in increased cellular GSH levels.

Interactions between essential and toxic elements in lead exposed children in Katowice, Poland

OBJECTIVES

To determine the influence of the essential element status on blood concentrations of lead and other toxic metals.

DESIGN AND METHODS

A group of 157 children from Katowice, an industrial area in Poland, was investigated for concentrations of lead and cadmium in whole blood, and mercury, selenium, zinc, copper, and magnesium in whole blood and serum. Relations between these elements, serum ferritin, hematological parameters, as well as serum selenoprotein P and glutathione peroxidase (GSH-px) were examined. Conversion factors for element concentrations (mumol to microgram): lead 207.19, cadmium 112.41, mercury 200.59, selenium 78.96, magnesium 24.31, copper 63.55, and zinc 65.

RESULTS

Blood lead was negatively associated with concentrations of selenium in whole blood and serum as well as selenoprotein P and glutathione peroxidase in serum. The association was mainly apparent at low blood lead concentrations, which may indicate an influence of selenium on the kinetics of lead, rather than an effect of lead on the selenium status. Children with low serum ferritin levels had statistically higher blood cadmium levels and a tendency for higher blood lead levels, indicating increased gastrointestinal absorption of these metals at reduced iron stores. Blood lead was negatively correlated with mean corpuscular hemoglobin concentration, which may reflect the effect of lead on hemoglobin synthesis. There was an association between blood mercury and selenium, indicating a common source of intake through fish consumption.

CONCLUSIONS

The results indicate that selenium and iron status may influence the kinetics of lead.

Decreased selenium concentration and glutathione peroxidase activity in blood and increase of these parameters in malignant tissue of lung cancer patients

We studied the selenium (Se) concentration in whole blood and plasma, glutathione peroxidase (GSH-Px) activity in red blood cells and plasma, as well as both of these parameters in cancerous and tumor-free lung tissue of lung cancer patients. Blood samples were taken from 84 cancer patients and 61 healthy controls. Normal and neoplastic lung tissues were obtained from 57 patients at the time of surgery. Se concentrations in whole blood and plasma were lower by 23% (p < 0.001) in patients compared with controls. GSH-Px activity in red cells was lower by 20.2% (p < 0.004) and in plasma by 11.7% (p < 0.05) in patients than in the control group. On the other hand, the tumor Se level was higher by 66.6% (p < 0.0001) and GSH Px activity by 49.5% (p < 0.0001) than in adjacent tumor-free tissue. No differences in Se concentrations and GSH-Px activities were found between squamous cell carcinoma and adenocarcinoma nor among the clinical stages of the disease. In the whole blood and plasma of cancer patients significantly lower Se concentrations were found in smokers than in nonsmokers. Significantly lower Se concentrations were also found among cancer patients who were smokers compared with controls. These findings show that in the blood of cancer the antioxidant ability, as measured by Se and GSH-Px, is reduced significantly. The cause of increased Se and GSH-Px in the malignant part of the lung is not understood and requires further studies.

Changes in blood selenium and glutathione concentrations and glutathione peroxidase activity in human pregnancy

Whole-blood and plasma selenium (Se) concentrations, red blood cell and plasma glutathione peroxidase activities, and red blood cell glutathione concentrations were investigated in 49 healthy pregnant women. Mean whole-blood and red blood cell Se concentrations started to decline after the 16th week and plasma Se after the 26th week of pregnancy. The lowest values were noted just before delivery. Negative correlations were found between the gestational age and both whole-blood and plasma Se concentrations: (r = -0.560 (p < 0.001) and r = -0.553 (p < 0.001), respectively. Plasma and red blood cell glutathione peroxidase activities started to decrease after the 20th and 30th week of pregnancy, respectively, and before delivery were significantly lower (p < 0.001) than during the 10th week of pregnancy. The red blood cell glutathione concentration increased significantly just before delivery. These results seem to confirm the supposition that in pregnant women with low or even moderate blood Se concentrations the requirement for the element significantly increases.

Non-operative removal of a parotid duct stone with a balloon angioplasty catheter

We illustrate a rapid and simple method for removal of a stone from the parotid duct using a balloon angioplasty catheter and digital subtraction imaging. No anaesthesia or surgical intervention is necessary.

Blood selenium concentrations and glutathione peroxidase activities in patients with breast cancer and with advanced gastrointestinal cancer

Recent prospective epidemiological studies have shown an association between a low prediagnostic serum selenium (Se) concentration and the risk of cancer. Se concentrations in whole blood and plasma, and the activity of red cell and plasma glutathione peroxidase (GSH-Px) were measured in patients with breast cancer, gastric cancer and colorectal cancer. The observed whole blood and plasma Se concentrations of healthy persons were 99.5 and 78.5 micrograms/L, respectively. Red cell and plasma GSH-Px activities of this group were: 21.0 U/g Hb and 256 U/L plasma. In all investigated cancer patients significantly lower whole blood and plasma Se concentrations, and significantly lower red cell and plasma GSH-Px activities were found, as compared with the values of healthy controls. Low Se concentrations of blood components may be indicative of increased cancer risk.