Tuning the Multiferroic Properties of BiFeO_{3} under Uniaxial Strain

More than twenty years ago, multiferroic compounds combining in particular magnetism and ferroelectricity were rediscovered. Since then, BiFeO_{3} has emerged as the most outstanding multiferroic by combining at room temperature almost all the fundamental or applicative properties that may be desired: electroactive spin wave excitations called electromagnons, conductive domain walls, or a low band gap of interest for magnonic devices. All these properties have so far only been discontinuously strain engineered in thin films according to the lattice parameter imposed by the substrate. Here we explore the ferroelectricity and the dynamic magnetic response of BiFeO_{3} bulk under continuously tunable uniaxial strain. Using elasto-Raman spectroscopy, we show that the ferroelectric soft mode is strongly enhanced under tensile strain and driven by the volume preserving deformation at low strain. The magnonic response is entirely modified with low energy magnon modes being suppressed for tensile strain above pointing out a transition from a cycloid to an homogeneous magnetic state. Effective Hamiltonian calculations show that the ferroelectric and the antiferrodistortive modes compete in the tensile regime. In addition, the homogeneous antiferromagnetic state becomes more stable compared to the cycloidal state above a +2% tensile strain close to the experimental value. Finally, we reveal the ferroelectric and magnetic orders of BiFeO_{3} under uniaxial strain and how the tensile strain allows us to unlock and to modify in a differentiated way the polarization and the magnetic structure.

POS0676 SURVIVAL OF THE FIRST COURSE OF BIOLOGIC OR JAK INHIBITOR IN RHEUMATOID ARTHRITIS: ASSOCIATION WITH THE CHOICE OF AGENT AND CONCOMITANT CONVENTIONAL SYNTHETIC DMARDS

Background:

After failure of conventional synthetic disease modifying anti-rheumatic drugs (csDMARDs) in the therapy of rheumatoid arthritis (RA), treatment may be escalated to biologic (bDMARDs) or JAK inhibitors (JAKi) (1). Analysis of drug survival can provide useful information on the effectiveness of these therapeutic schemes.

Objectives:

to evaluate the association of the choice of therapeutic agent with the survival of treatment course in RA patients receiving their first bDMARD or JAKi.

Methods:

BiobadaBrasil is a multicentric registry-based cohort study of Brazilian patients starting their first bDMARD/JAKi (2). This analysis includes RA patients recruited from Jan 2009 to Oct 2019, followed-up over the first course of treatment with a bDMARD/JAKi until censoring (latest date, Nov 19, 2019) or occurrence of the outcome of interest. A treatment course is defined as a period during which the medication scheme does not change, except for dose adjustments. The primary outcome was the interruption of treatment course for any reason (except for pregnancy or disease remission); interruption of treatment due to adverse events (AEs) or death and due to inefficacy served as secondary outcomes. Multivariate Cox proportional hazards models were used for analyses.

Results:

In total, 1177 patients (3800 patient-years [PY]) were enrolled. The overall incidence of treatment interruption was 17.5/100 PY. Adalimumab was the most frequently prescribed agent, followed by infliximab (n= 267). The hazards ratios (HR) of the primary and secondary outcomes are presented in Table 1. Figure 1 compares the survival of treatment curves of different bDMARDs/JAKi.

Table 1.

Hazard ratios (HR) of interruption of therapy course of each therapeutic agent (the reference category for bDMARDs/ JAKi is infliximab). Results are HR, 95% CIs, and P values*.

Agent (number of patients)Interruption for any reason (665 events)Interruption due to adverse events or death (196 events)Interruption due to inefficacy (319 events)Adalimumab (354)0.83 (0.68 to 1.01), P= 0.0620.68 (0.48 to 0.96), P=0.0291.08 (0.80 to 1.44), P=0.621Etanercept (257)0.81 (0.66 to 1.01), P=0.0630.56 (0.37 to 0.83), P=0.0040.93 (0.68 to 1.29), P=0.674Certolizumab (80)0.74 (0.47 to 1.16), P=0.1850.33 (0.13 to 0.86), P=0.0241.32 (0.74 to 2.35), P=0.350Golimumab (53)0.86 (0.53 to 1.38), P=0.5300.46 (0.18 to 1.19), P=0.1111.07 (0.53 to 2.15), P=0.849JAKi (tofacitinib) (59)0.54 (0.30 to 0.99), P=0.0470.19 (0.04 to 0.82), P=0.0260.89 (0.41 to 1.96), P=0.779Rituximab (48)0.87 (0.55 to 1.37), P=0.5400.48 (0.20 to 1.18), P=0.1090.58 (0.26 to 1.34), P=0.205Abatacept (30)0.52 (0.25 to 1.07), P=0.0770.46 (0.14 to 1.56), P=0.2150.46 (0.14 to 1.52), P=0.203Tocilizumab (29)0.29 (0.14 to 0.63), P=0.0020.40 (0.12 to 1.30), P=0.1260.28 (0.09 to 0.90), P=0.033Methotrexate (792)0.95 (0.79 to 1.14), P=0.5610.86 (0.62 to 1.19), P=0.3620.98 (0.75 to 1.28), P=0.860Leflunomide (497)1.17 (0.99 to 1.39), P=0.0611.44 (1.06 to 1.96), P=0.0201.02 (0.80 to 1.30), P=0.856Sulfasalazine (48)1.18 (0.80 to 1.75), P=0.4011.94 (1.07 to 3.54), P=0.0300.85 (0.45 to 1.59), P=0.605Antimalarials (230)0.80 (0.65 to 0.98), P=0.0270.67 (0.45 to 0.99), P=0.0430.67 (0.50 to 0.92), P=0.011

* All tests adjusted for other variables presented in the table and for age, baseline DAS28, disease duration, gender, smoking, seropositivity (RF/anti-CCP), previous malignancy, diabetes, hypertension, hypercholesterolemia, renal failure, ischemic cardiomyopathy, COPD, heart failure, use of corticosteroids, starting year, hypercholesterolemia, osteoporosis, hepatitis B and C.

Conclusion:

In our study, infliximab was related to an overall higher hazard of treatment course interruption than tolicizumab and tofacitinib, and higher hazard of interruption due to AEs than most other anti-TNF agents and tofacitinib. Maintaining antimalarials in patients receiving advanced therapies for RA may reduce interruption of treatment due to inefficacy and AEs.

Disclosure of Interests:

None declared

How has COVID-19 affected the treatment of osteoporosis? An IOF-NOF-ESCEO global survey

The effects of COVID-19 have the potential to impact on the management of chronic diseases including osteoporosis. A global survey has demonstrated that these impacts include an increase in telemedicine consultations, delays in DXA scanning, interruptions in the supply of medications and reductions in parenteral medication delivery.

INTRODUCTION

The COVID-19 pandemic has had profound effects on the health of the global population both directly, via the sequelae of the infection, and indirectly, including the relative neglect of chronic disease management. Together the International Osteoporosis Foundation and National Osteoporosis Foundation sought to ascertain the impact on osteoporosis management.

METHODS

Questionnaires were electronically circulated to a sample of members of both learned bodies and included information regarding the location and specialty of respondents, current extent of face to face consultations, alterations in osteoporosis risk assessment, telemedicine experience, alterations to medication ascertainment and delivery and electronic health record (EHR) utilisation. Responses were collected, quantitative data analysed, and qualitative data assessed for recurring themes.

RESULTS

Responses were received from 209 healthcare workers from 53 countries, including 28% from Europe, 24% from North America, 19% from the Asia Pacific region, 17% from the Middle East and 12% from Latin America. Most respondents were physicians (85%) with physician assistants, physical therapists and nurses/nurse practitioners represented in the sample. The main three specialties represented included rheumatology (40%), endocrinology (22%) and orthopaedics (15%). In terms of the type of patient contact, 33% of respondents conducted telephone consultations and 21% video consultations. Bone mineral density assessment by dual-energy X-ray absorptiometry (DXA) usage was affected with only 29% able to obtain a scan as recommended. The majority of clinicians (60%) had systems in place to identify patients receiving parenteral medication, and 43% of clinicians reported difficulty in arranging appropriate osteoporosis medications during the COVID-19 crisis.

CONCLUSIONS

To conclude through surveying a global sample of osteoporosis healthcare professionals, we have observed an increase in telemedicine consultations, delays in DXA scanning, interrupted supply of medications and reductions in parenteral medication delivery.

Correction to: How has COVID-19 affected the treatment of osteoporosis? An IOF-NOF-ESCEO global survey

A Correction to this paper has been published: 10.1007/s00198-021-05905-7

Age-dependent hepatic alterations induced by a high-fat high-fructose diet

OBJECTIVE

The present study aimed to evaluate and clarify how the age at which the intake of a high-fat and high-fructose diet begins can affect animals' livers.

METHODS

Thirty-eight male wistar rats aged 6 and 12 weeks were fed a high-fat and high-fructose diet for 13 weeks. Inflammatory cytokines, hepatic glycogen, serum and hepatic triacylglycerol and pAkt protein content in the liver were assessed. Percentage of weight gained, and visceral adiposity were also evaluated.

RESULTS

Young animal presented increased hepatic triacylglycerol and decreased glycogen, while adult animals had no significant alterations regarding its contents. IL6 and IL10 to IL6 ratio were also altered in young animals exposed to HFHF, while adult animals fed with HFHF had only increases in TNF-α. Both groups which received HFHF had increased serum triacylglycerol and visceral adiposity. However, only young animals gained more relative weight and had greater final body weight, gains which were related to alterations found in hepatic triacylglycerol and glycogen.

CONCLUSION

Age of which consumption begins interferes in how the liver deals with an excess of nutrient and subsequent proinflammatory stimulation, leading to different phenotypes.

Influence of soil conditions on the distribution coefficients of 226Ra in natural soils

In order to clarify some of the assumptions and approximations about the use of the distribution coefficient K_d for ²²⁶Ra in soils, a systematic study has been performed using centrifugation to extract the soil solution. The separated fractions of the soil solution have different kinetics with respect to the sorption process in the soil, which may in turn condition the final chemical composition and even the speciation of the radionuclides in solution. In the experimental design of this study three factors were considered: the moisture level in the incubation process, incubation time and the speed of centrifugation. Also, three levels were chosen for each factor. In order to analyze the influence of the structural characteristics of the soil, this study was performed with three textural fractions: coarse sand, fine sand, and silt and clay, obtained from an only soil. Also, the soil was naturally enriched with radionuclides of the ²³⁸U series. An analysis of variance (ANOVA) was performed in order to assess the influence of the factors studied on the distribution coefficient of ²²⁶Ra. The results indicate that different behaviors can be observed depending on the structural characteristic of the soil. In the case of particle size, the soil with the largest grain size showed that the incubation process parameters influence the equilibrium level achieved, while in the case of the smallest edaphic particles, radium is not homogeneously distributed in the soil solution and the K_d value is dependent on the speed of centrifugation.

Effect of Fat Intake on the Inflammatory Process and Cardiometabolic Risk in Obesity After Interdisciplinary Therapy

Changes in diet and eating behavior along with excessive consumption of sugar or fat and a sedentary lifestyle are related to increased obesity and its associated comorbidities. The aim of this study was to investigate the role of the type of macronutrients on specific health benefits associated with the weight loss in treating obesity. A total of 30 obese women (34.89±3.04 kg/m(2) and 43.3±5.34 years) participated in an interdisciplinary therapy approach to lifestyle change, which consisted of nutritional counseling, exercise, and psychological therapy for over a period of 26 weeks. The profile was obtained by anthropometric measurements and body composition by bioelectrical impedance analysis (BIA). Usual food intake was assessed with 3-day food record diaries and blood tests were used to determine metabolic and adipokines parameters. After therapy, there was significant reduction in all anthropometric and body composition variables. Food consumption also decreased while still providing adequate nutrient intake. There was significant improvement in LDL-cholesterol, PAI-1, leptin, CRP, ICAM-1, and VCAM-1. Lower dietary carbohydrate and fat intake led to weight loss. The effect of lower carbohydrate intake on weight loss is related to changes in body composition and leptin levels. Weight loss by reducing fat intake modified the inflammatory process and cardiovascular risk, indicating dietary fat as an independent predictor factor of cell adhesion molecules. Therefore, decreasing dietary fat consumption had greater impact on the inflammatory process on obese individuals. Our results show that the type of macronutrient influences the health benefits associated with weight loss.

Synthesis of cyclohexapeptides as antimalarial and anti-trypanosomal agents

Azolic and non-azolic cyclohexapeptides were obtained and/or evaluated as promising antimalarial and/or anti-trypanosomal agents.

A multibiomarker approach in the clam Ruditapes decussatus to assess the impact of pollution in the Ria Formosa lagoon, South Coast of Portugal

The Ria Formosa lagoon is an ecosystem whose water quality reflects the anthropogenic influence upon the surrounding areas. In this lagoon, the clam Ruditapes decussatus has a great economical importance and has been widely used as a biomonitor. A multibiomarker approach (δ-aminolevulinic acid dehydratase, metallothionein, lipid peroxidation, acetylcholinesterase, alkali-labile phosphates, DNA damage) was applied to assess the environmental quality of this ecosystem and the accumulation of contaminants and their potential adverse effects on clams. Clams were sampled in different shellfish beds in the period between July 2007 and December 2008 and abiotic parameters (temperature, salinity, pH and dissolved oxygen of seawater and organic matter in the sediment), condition index, metals (Cd, Cu, Zn, Ni, Pb), TBTs and PAHs concentrations were measured in clam tissues. Data was integrated using Principal Component Analyses and biomarker indices: IBR (Integrated Biomarker Response) and HSI (Health Status Index). This multibiomarker approach enabled discrimination of a time and space trend between sites with different degrees of anthropogenic contamination, identifying one of them (site 2) as the most stressful and summer months as the most critical period for clams due to an increase of environmental stress (anthropogenic pressure along with extreme environmental conditions, e.g. temperature, dissolved oxygen, organic matter in the sediments, etc). The selected biomarkers provided an integrated response to assess the environmental quality of the system, proving to be a useful approach when complex mixtures of contaminants occur.

Sleep and muscle recovery: endocrinological and molecular basis for a new and promising hypothesis

Sleep is essential for the cellular, organic and systemic functions of an organism, with its absence being potentially harmful to health and changing feeding behavior, glucose regulation, blood pressure, cognitive processes and some hormonal axes. Among the hormonal changes, there is an increase in cortisol (humans) and corticosterone (rats) secretion, and a reduction in testosterone and Insulin-like Growth Factor 1, favoring the establishment of a highly proteolytic environment. Consequently, we hypothesized that sleep debt decreases the activity of protein synthesis pathways and increases the activity of degradation pathways, favoring the loss of muscle mass and thus hindering muscle recovery after damage induced by exercise, injuries and certain conditions associated with muscle atrophy, such as sarcopenia and cachexia.

Cardiac anti-remodelling effect of aerobic training is associated with a reduction in the calcineurin/NFAT signalling pathway in heart failure mice

Cardiomyocyte hypertrophy occurs in response to a variety of physiological and pathological stimuli. While pathological hypertrophy in heart failure is usually coupled with depressed contractile function, physiological hypertrophy associates with increased contractility. In the present study, we explored whether 8 weeks of moderate intensity exercise training would lead to a cardiac anti-remodelling effect in an experimental model of heart failure associated with a deactivation of a pathological (calcineurin/NFAT, CaMKII/HDAC) or activation of a physiological (Akt-mTOR) hypertrophy signalling pathway. The cardiac dysfunction, exercise intolerance, left ventricle dilatation, increased heart weight and cardiomyocyte hypertrophy from mice lacking alpha(2A) and alpha(2C) adrenoceptors (alpha(2A)/alpha(2C)ARKO mice) were associated with sympathetic hyperactivity induced heart failure. The relative contribution of Ca(2+)-calmodulin high-affinity (calcineurin/NFAT) and low-affinity (CaMKII/HDAC) targets to pathological hypertrophy of alpha(2A)/alpha(2C)ARKO mice was verified. While nuclear calcineurin B, NFATc3 and GATA-4 translocation were significantly increased in alpha(2A)/alpha(2C)ARKO mice, no changes were observed in CaMKII/HDAC activation. As expected, cyclosporine treatment decreased nuclear translocation of calcineurin/NFAT in alpha(2A)/alpha(2C)ARKO mice, which was associated with improved ventricular function and a pronounced anti-remodelling effect. The Akt/mTOR signalling pathway was not activated in alpha(2A)/alpha(2C)ARKO mice. Exercise training improved cardiac function and exercise capacity in alpha(2A)/alpha(2C)ARKO mice and decreased heart weight and cardiomyocyte width paralleled by diminished nuclear NFATc3 and GATA-4 translocation as well as GATA-4 expression levels. When combined, these findings support the notion that deactivation of calcineurin/NFAT pathway-induced pathological hypertrophy is a preferential mechanism by which exercise training leads to the cardiac anti-remodelling effect in heart failure.

Radiofrequency ablation of atrial arrhythmias after previous open-heart surgery

AIM

To report the results of ablation of atrial arrhythmias (AA) after previous open-heart surgery.

METHODS

Nineteen patients [50+/-11 years, 11 women] underwent ablation of symptomatic AAs after previous open-heart surgery. In 11 patients mapping was performed using conventional multielectrode catheters. In the other eight patients CARTO electro-anatomical mapping system was used to supplement conventional mapping.

RESULTS

After conventional mapping, 10/11 patients (91%) were found to have typical atrial flutter (AFL). The cavotricuspid isthmus was successfully ablated in these 10 patients. CARTO combined with conventional mapping showed that 7 of 8 patients had one macro-reentry right atrial circuit. The remaining patient had two focal atrial tachycardias. CARTO-guided ablation was successful in all eight patients (100%). After follow-up of 12+/-11 months, 2/18 patients (11%) had recurrence of either the same (n=1) or a new (n=1) AA.

CONCLUSIONS

AAs after previous open-heart surgery can be ablated successfully (>90%) with a low recurrence rate (11%) at 1-year follow-up. Typical AFL was found frequently (14/19 patients, 72%). This could be ablated successfully, often, after conventional mapping alone. CARTO helps to uncover peri-scar reentry and guide the ablation by creating a line of block connecting the scar to another landmark (unconventional isthmus).

Swimming training increases cardiac vagal activity and induces cardiac hypertrophy in rats

The effect of swimming training (ST) on vagal and sympathetic cardiac effects was investigated in sedentary (S, N = 12) and trained (T, N = 12) male Wistar rats (200-220 g). ST consisted of 60-min swimming sessions 5 days/week for 8 weeks, with a 5% body weight load attached to the tail. The effect of the autonomic nervous system in generating training-induced resting bradycardia (RB) was examined indirectly after cardiac muscarinic and adrenergic receptor blockade. Cardiac hypertrophy was evaluated by cardiac weight and myocyte morphometry. Plasma catecholamine concentrations and citrate synthase activity in soleus muscle were also determined in both groups. Resting heart rate was significantly reduced in T rats (355 +/- 16 vs 330 +/- 20 bpm). RB was associated with a significantly increased cardiac vagal effect in T rats (103 +/- 25 vs 158 +/- 40 bpm), since the sympathetic cardiac effect and intrinsic heart rate were similar for the two groups. Likewise, no significant difference was observed for plasma catecholamine concentrations between S and T rats. In T rats, left ventricle weight (13%) and myocyte dimension (21%) were significantly increased, suggesting cardiac hypertrophy. Skeletal muscle citrate synthase activity was significantly increased by 52% in T rats, indicating endurance conditioning. These data suggest that RB induced by ST is mainly mediated parasympathetically and differs from other training modes, like running, that seems to mainly decrease intrinsic heart rate in rats. The increased cardiac vagal activity associated with ST is of clinical relevance, since both are related to increased life expectancy and prevention of cardiac events.

[Trans-surgical ablation of atrial flutter in patients treated with closure of atrial septal defect. Pilot project]

Atrial flutter is one of the most common arrhythmias in patients with atrial septal defect, after surgery 14% of patients can develop it and may be associated with high morbidity. In this study we performed prophylactic and therapeutic ablation of atrial flutter during atrial septal closure surgery drawing 4 lines; line 1, isthmus cavo-tricuspid, the area between the inferior vena cava and the tricuspid ring; line 2, the area between coronary sinus ostium and inferior vena cava; line 3, the area between tricuspid valve annulus and coronary sinus ostium; and line 4, the area between lateral atriotomy and atrial septal defect. Twenty-one patients were included, 6 (28.5%) patients had atrial flutter before surgery and 15 (71.4%) were in sinus rhythm. There were no new cases of atrial flutter, but at six months follow up 2 (33.3%) patients recidivated with atrial flutter. One patient developed high degree atrio-ventricular block and a pacemaker had to be implanted. Older age at the time of surgery and high systolic pulmonary pressure were significantly higher in those patients with atrial flutter before surgery and in patients with arrhythmias recurrence. Ablation of atrial flutter during atrial septal closure surgery can be a good option for the treatment and prevention of atrial arrhythmias, but more studies are still needed.

O-glycosylation in Echinococcus granulosus: identification and characterization of the carcinoma-associated Tn antigen

In the present work we demonstrate that the cancer-associated O-glycosylated Tn antigen (GalNAc-O-Ser/Thr) is expressed by the cestode Echinococcus granulosus. This antigen was detected in both larval and adult worm extracts, with the highest specific activity observed in the adult excretion/secretion preparation. Histochemical analysis showed that Tn is preferentially expressed in the parenchyma in both parasite stages and the external part of tegument in adult worms. A similar pattern was observed for sialyl-Tn, a related O-linked antigen. Tn glycoproteins from protoscoleces were resolved by SDS-PAGE in two main components of 43 and 49 kDa. After purification, this material was reactive with lectins which bind GlcNAc/sialic acid, GalNAc, and T antigen. In a preliminary evaluation, high levels of Tn antigen were detected in serum samples from patients with hydatid cyst, suggesting that the measure of Tn in serum could be a biomarker of this disease, although extensive work is necessary in order to determine the clinical usefulness of this assay. The results reported here, the first evidence of O-glycosylation pathways in E. granulosus and the presence of Tn antigen in cestodes, suggest that the evaluation of O-glycosylated antigens might give new insights in the host-parasite relationship.

[Sudden death in intermittent Wolff Parkinson White syndrome]

Sudden death is a rare condition in asymptomatic patients with asymptomatic intermittent Wolff Parkinson syndrome (WPW); for this reason it is believed that these patients should not undergo to radiofrequency ablation. We report an asymptomatic 44 year old man who developed ventricular fibrillation with a pre-excited RR interval less than 200 msec during atrial fibrillation, as a first manifestation of WPW syndrome. The Holter monitoring showed intermittent pre-excitation at low heart rate (70 bpm). During the electrophysiological study a successfully radiofrequency catheter ablation of a right posteroseptal accessory pathway was performed. We concluded that intermittent pre-excitation may not be used to identify patients who are at risk of sudden death. Radiofrequency catheter ablation should be recommended in those patients with a very high success rate, and a low incidence of serious complications.

Radiofrequency catheter ablation for the treatment of supraventricular tachycardias in children and adolescents

We report our experience in radiofrequency catheter ablation between April, 1992 and December, 1998, in which we treated 287 patients less than 18 years of age (mean 14.3 +/- 3.1 years) with supraventricular tachycardia. Accessory, pathways were the arrhythmic substrate in 252 of the patients (87.8%), the patients having a total of 265 accessory pathways. Atrioventricular nodal re-entry was the cause of tachycardia in 26 patients (9.0%), while atrial flutter was detected in the remaining 9 patients (3.1%). We were able successfully to eliminate the accessory pathway in 236 patients (89%), but 25 patients had recurrent arrhythmias. Ablation proved successful in all cases of atrioventricular node re-entry tachycardia, the slow pathway being ablated in 25 patients, and the fast pathway in only one case. Recurrence of the arrhythmia occurred in three patients (11.5%). We performed a second ablation in these children, all then proving successful. The ablation was successful in all cases of atrial flutter, with one recurrence (11.1%). Overall, therefore, ablation was immediately successful in 271 patients (94.4%), with a recurrence of the arrhythmia in 29 cases (10.7%). The incidence of serious complications was 2.09%. There was one late death due to infective endocarditis, 3 patients suffered complete heart block, 1 had mild mitral regurgitation, and 1 patient developed an haematoma in the groin. We conclude that radiofrequency catheter ablation can now be considered a standard option for the management of paroxysmal supraventricular tachycardias in children and young adults.

Cytogenetics of epithelial hyperplasias of the human breast

Generally, benign breast lesions behave like innocuous and limited proliferations; however, sometimes they can represent precancerous pathologies. The cytogenetic analysis of five mammary epithelial hyperplasias is reported. Four cases had clonal chromosome alterations. All of the cases presented a modal number of 46 chromosomes. Chromosome 9 monosomies and chromosome 1 deletions were common in these benign tumors. The study of benign proliferations of the breast may reveal a possible relationship between chromosomal alterations and the conditions of the tissue.

[Focal atrial fibrillation treated with radiofrequency]

Atrial fibrillation is usually thought to be due to multiple circulating reentrant wavelets. From previous studies, a focal mechanism is considered to be very unlikely. This focal source could be successfully treated by radiofrequency catheter ablation. We report a patient without structural heart disease, but with multiple episodes of syncope and palpitations related to atrial tachycardia and atrial fibrillation. Electrophysiological study demonstrated that all atrial arrhythmias were due to one focus located in the left atrium at the ostium of the left superior pulmonary vein that was successfully treated with the use of a mean of three radiofrequency pulses, without complications. The pulmonary veins are an important source of ectopic beats, initiating frequent paroxysm of atrial fibrillation. These foci respond to treatment with radiofrequency ablation.

Biochemical and functional characterization of the Tn-specific lectin from Salvia sclarea seeds

SSL, the lectin isolated from Salvia sclarea seeds, recognizes the Tn antigen (GalNAcalpha-O-Ser/Thr), a specific marker of many human carcinomas. Two-dimensional electrophoresis, amino-acid and amino-sugar analysis, and MALDI-TOF MS showed that SSL is an acidic (pI 5.5), 60-61-kDa dimeric glycoprotein composed of apparently identical subunits linked by a single disulfide bond. The apparent molecular mass of SSL in solution determined by equilibrium sedimentation analytical ultracentrifugation was 59 +/- 9 kDa. This value did not change in the pH range 2.5-8.5, indicating that SSL does not associate into higher order structures. Tandem mass spectrometry and methylation analysis of N-glycans released from SSL by hydrazinolysis indicated that SSL possesses 2-3 glycosylation sites occupied with the typical plant glycans Manalpha1-6[(Manalpha1-3)(Xylbeta1-2)]Manbeta1-4 -GlcNAcbeta1-4(Fucalp ha1-3)GlcNAc and [(Manalpha1-3/6)(Xylbeta1-2)]Manbeta1-4-GlcNAcbeta1 -4(Fucalpha1-3)Glc NAc. The influence of adjacent Tn structures on the binding of two Tn-specific lectins (SSL and the isolectin B4 from Vicia villosa) and an anti-Tn monoclonal antibody (mAb 83D4) was evaluated using synthetic Tn glycopeptides. The binding of both lectins to the synthetic Tn glycopeptides was independent of the density of Tn structures. On the other hand, mAb 83D4 only reacted with glycopeptides displaying two or three consecutive Tn structures.

[Permanent rhythm and conduction disorders in patients surgically treated for atrial septal defect]

Atrial septal defect (ASD) represents a congenital heart disease with good prognosis, however, atrial arrhythmias are well-documented complications. A retrospective study was performed to assess the prevalence, types and risk factors of arrhythmias in patients with ASD after surgical correction. 920 patients were analyzed retrospectively; cases with complex congenital heart disease or another systemic alteration conditioning atrial rhythm disturbances were excluded. 460 patients with ASD corrected by surgery were followed at least for six months after the procedure. 29.3% of patients were male and 70.7% female. Direct closure was performed in 63%, pericardial patch was installed in 27%. 29 patients (6.3%) had conduction and rhythm disturbances before surgery, the most common arrhythmias were atrial flutter (34.5%), first degree A-V block (31%) and low right atrial rhythm (27.6%). Six months after atrial defect closure, 65 patients (14.13%) had arrhythmias, 44.6% atrial flutter, 20% ectopic atrial rhythm, 10.8% sick sinus syndrome. The risk of atrial arrhythmias was related to age at surgical repair, pulmonary hypertension and atrial arrhythmias before surgery.

[A complete atrioventricular block during exertion]

Exercise-induced atrioventricular (AV) block in patients with normal electrocardiogram at rest is uncommon. We report the clinical features of two patients with AV block during treadmill test. The first patient was a woman of 54 years of age with presyncope on exercise. She developed complete AV block during exercise testing without evidence of ischemic myocardial disease. Electrophysiologic study documented distal AV block. The second patient was a man 31 years old who developed angina and third-degree AV block with depression of ST segment during treadmill test. Myocardial perfusion study suggested ischemic heart disease. He received anti-ischemic drugs with improvement of symptoms. A control exercise testing demonstrated normal AV conduction and electrophysiologic study was normal. In the first case, exercise AV block was probably due to abnormal His Purkinje conduction system refractoriness to autonomic modulation, while in second case AV block was secondary to ischemic heart disease. Third-degree AV block at exercise can be present in patients without conduction system abnormalities at rest. Exercise-induced infra-Hisian AV block must be treated with pacing until ischemic heart disease has been ruled out.

[Complete congenital heart block. Its natural history and evolution]

This study describes the natural history and evolution of 67 patients with congenital auriculoventricular heart block admitted in the Instituto Nacional de Cardiología "Ignacio Chávez", Mexico, D.F. from 1944 to 1998. There were 35 (52%) females and 32 (47%) males, with mean follow up period of 93.7 +/- 104 months. Most of the patients were without structural cardiovascular disease (90%). The most frequent symptoms were dyspnea and syncope. Electrocardiograms showed a ventricular heart rate of 42.2 +/- 9 beats/minute. 85.7% of patients had a supra-Hisian complete heart block. In 31% of patients a pacemaker was implanted because syncope. Overall mortality was 4.4% and malignant ventricular arrhythmias were the principal contributors. Risk factors for mortality identified in this study were junctional escape rhythm lower than 50 beats/minute, inappropriate chronotropic response during exercise, R-R interval prolongation at night, enlargement of cardiac chambers, depressed left ventricular ejection fraction and prolonged QT interval. In all of these conditions we recommend permanent pacemaker implantation.

[Automatic, implantible cardioverter-defibrillator in a patient with chronic Chagas cardiopathy and sustained ventricular tachycardia]

We studied a 48 years old woman, with chronic Chagasic cardiopathy, manifested with cardiomegaly, heart failure and syncope, due to a sustained ventricular tachycardia (SVT) of two different configurations (left bundle branch block and right bundle branch block). During electrophysiological testing, both types of ventricular tachycardia were reproduced. Successful ablation therapy of the right branch of His was performed due to suspicion of the bundle branch reentrant tachycardia, with a left bundle branch block. The patient continued to show SVT episodes, now with right bundle branch block pattern. Cardioverter Defibrillator was implanted. We report this case due to the rare frequency of Chagas' disease, where it could be a cause of heart disease, since the existence of the parasite (trypanosoma cruzi) and its vector (Triatoma) has been identified in some rural and suburban zones in the state of Aguascalientes, Mexico.

[The healthy life]

This study is based on a comparison of the habits and opinions of a group of pupils on entering the Damaia Preparatory School (5th and 6th years of education) and of the same group on leaving this School. Its aim is to contribute towards an adequate education for health at school in order to promote healthy living habits. The study was based on the comparison of data obtained from two random samples, chosen from the same group of pupils when entering (n1 = 36 out of a total of 368) and leaving (n2 = 32 out of a total of 164) the above mentioned school. The collection of data was carried out by means of a multiple-choice questionnaire given to a total of 532 pupils. The results demonstrated that the frequencies have changed in the following way: a) bathing has increased; b) tea drinking has decreased; c) the image of the teacher as a smoker has become less frequent; d) the number of pupils who have tried alcoholic beverages has increased; e) mother's smoking habits have increased. The other trends that were found in the study showed that there were no significant changes in either the behaviour or opinions that had been studied.

[Acute pancreatitis. An analysis of 91 consecutive cases (1988-1991) with a brief review of the literature)]

Acute pancreatitis (AP) remains a subject of great controversy from the standpoint of its aetiology, pathogeny and treatment. We present a study of 91 patients with AP consecutively admitted to a surgical ward. 50 Women and 41 men with a mean age of 59 +/- 19 years were treated. The aetiology of AP was attributed to gallstones in 54 patients, alcohol in 22, ERPC and trauma; in 14 patients the aetiology was considered idiopathic. The most frequent signs and symptoms were pain, vomiting, abdominal tenderness, jaundice and fever. The mean number of Ranson's prognostic criteria was 3 +/- 1.5 and 29 patients (31%) had more than three. Initial management was conservative in 84 patients (92.3%) and seven were operated on admission (acute abdomen in four, septic shock in two and common duct obstruction in another). Mortality rate was 11% (n = 10) and in 24 patients (26.3%) there were complications of AP. Most of the patients (80%) began oral feeding a week after admission. The mean number of Ranson's criteria of patients deceased was 5.4 +/- 1.6 and of those who survived was 2.8 +/- 1.3 (p < 0.001). Follow-up of patients allowed us to see that in five (5.5%) there was a relapse of AP.

Bioprosthetic endocarditis due to Cryptococcus neoformans

Fungal prosthetic endocarditis continues to be a lethal complication of cardiac valve replacement. We describe a patient with culture-proved Cryptococcal endocarditis and myocarditis whose non-regurgitant xenograft aortic prosthesis was successfully replaced urgently upon the occurrence of new 1st degree A-V block in the third postoperative week. Operative intervention, including vigorous debridement of the aortic root, is effective in postoperative prosthetic fungal infections involving the myocardium. The patient described herein is now infection-free, with a non-regurgitant valve, one and one-half years following operation.