Application and stability of cathodes with manganese dioxide nanoflowers supported on Vulcan by Fenton systems for the degradation of RB5 azo dye.

This work describes the electrochemical degradation of Reactive Black 5 (RB5) by two methods: electrochemical and photo-assisted electrochemical degradation with and without a Fenton reagent. Two anodes were used, Pt and boron-doped diamond (BDD, 2500 ppm), and the cathode was 3% MnO2 nanoflowers (NFMnO2) on a carbon gas diffusion electrode (GDE). An electrochemical cell without a divider with a GDE with 3% w/w NFMnO2/C supported on carbon Vulcan XC72 was used. The decolorization efficiency was monitored by UV-vis spectroscopy, and the degradation was monitored by Total Organic Carbon (TOC) analysis. For dissolution monitoring, aliquots (1 mL) were collected during the degradation. After 6 h of H2O2 electrogeneration, the manganese concentration in the RB5 solution was only 23.1 ±â€¯1.2 µg L-1. It was estimated that approximately 60 µg L-1 (<0.2%) of manganese migrated from the GDE to the solution after 12 h of electrolysis, which indicated the good stability of the GDE. The photoelectro-Fenton-BDD (PEF-BDD) processes showed both the best color removal percentage (∼93%) and 91% of mineralization. The 3% NFMnO2/C GDE is promising for RB5 degradation.

Treatment of anaemia with erythropoiesis-stimulating agents in patients with chronic kidney disease does not lower mortality and may increase cardiovascular risk: a meta-analysis.

BACKGROUND/AIMS: Interpretation of the results of earlier meta-analyses in chronic kidney disease (CKD) patients on the impact of anaemia treatment with erythropoiesis-stimulating agents (ESAs) on clinical outcomes has been hampered by the inclusion of small trials and trials of short duration. We re-evaluated the benefits and harms of treating anaemia, including only relevant clinical trials. METHODS: We conducted a systematic review and meta-analysis of randomised controlled trials performed in adults with CKD which allocated patients to different doses of ESAs, and we compared the effect of these interventions on vascular access thrombosis, stroke, risk of end-stage renal disease (ESRD) and all-cause mortality. Additional inclusion criteria were studies with a duration of at least 1 year and enrolling more than 500 participants. RESULTS: Five trials (7,902 participants) met the inclusion criteria and were included in the meta-analysis. The number of patients enrolled in each trial ranged from 596 to 4,038. The mean/median duration of follow-up ranged from 14 to 36 months. A higher haemoglobin target was associated with increased risk of vascular access thrombosis (RR 1.343; 95% CI 1.162-1.554; p = 0.0005) and stroke (RR 1.735; 95% CI 1.323-2.275; p = 0.0005), and no effect on risk of ESRD (RR 1.089; 95% CI 0.986-1.203; p = 0.094) or all-cause mortality (RR 1.148; 95% CI 0.977-1.350; p = 0.093). CONCLUSION: In CKD patients, treatment of anaemia with ESAs targeting a higher haemoglobin value does not lower mortality or reduce the risk of ESRD, and may increase cardiovascular risk.

Prevention of cytomegalovirus disease in renal transplantation: single-center experience.

Cytomegalovirus (CMV) infection and CMV disease remain important issues in renal transplantation. Incidence depends on individual patient risk. There are different possible strategies for CMV prophylaxis. In our center CMV prevention includes prophylaxis with low-dose valganciclovir for all high-risk recipients; for the remaining patients, valganciclovir is only prescribed when there is evidence of CMV replication. All recipients are monitored for viral replication. We evaluated the results of this preventive strategy in all 135 patients who underwent transplantation between 2006 and 2007 in our center. Average follow-up time was 16 months (6-30 months). Fifty-one recipients (38%) received CMV prophylaxis. The median duration of prophylaxis was 84 days. In 37% of the recipients (50 patients) CMV antigenemia became positive, and were given therapeutic doses of valganciclovir. Of these patients, 32% were high-risk recipients undergoing prophylaxis. CMV infection rate was 40% in the group not receiving prophylaxis. No association was observed between CMV infection and prophylaxis duration. However, 50% of patients who suspended prophylaxis before completion of the first 3 months became infected. There were 3 cases of CMV disease (2.2%). Leukopenia was seen in 34% of patients receiving prophylaxis. Valganciclovir prophylaxis for high-risk patients seems to be effective and safe among subjects who complete the full duration of treatment. Despite CMV-positive antigenemia in 40% of patients not undergoing prophylaxis, pre-emptive therapy with valganciclovir was effective to prevent CMV disease, but close monitoring is essential for disease prevention.

Differential effects of Notch ligands Delta-1 and Jagged-1 in human lymphoid differentiation.

Notch signaling is known to differentially affect the development of lymphoid B and T cell lineages, but it remains unclear whether such effects are specifically dependent on distinct Notch ligands. Using a cell coculture assay we observed that the Notch ligand Delta-1 completely inhibits the differentiation of human hematopoietic progenitors into the B cell lineage while promoting the emergence of cells with a phenotype of T cell/natural killer (NK) precursors. In contrast, Jagged-1 did not disturb either B or T cell/NK development. Furthermore, cells cultured in the presence of either Delta-1 or Jagged-1 can acquire a phenotype of NK cells, and Delta-1, but not Jagged-1, permits the emergence of a de novo cell population coexpressing CD4 and CD8. Our results thus indicate that distinct Notch ligands can mediate differential effects of Notch signaling and provide a useful system to further address cell-fate decision processes in lymphopoiesis.

Atrial flutter ablation with a new radiofrequency catheter.

OBJECTIVE: To assess the performance of a new radiofrequency catheter, specially designed for inferior vena cava-tricuspid annulus (IVC-TA) isthmus ablation, in the treatment of atrial flutter. PATIENTS: IVC-TA isthmus ablation was performed in thirteen patients, eleven men and two women, aged 60 +/- 12, with a diagnosis of typical atrial flutter, symptomatic despite anti-arrhythmic therapy. The flutter was present for more than one year in seven patients and was paroxysmal in the remainder. The echocardiogram showed atrial enlargement in six patients. Atrial flutter was an isolated phenomenon in seven patients and in the remainder was associated with arterial hypertension (two patients), ischemic heart disease (two patients) and dilated cardiomyopathy (two patients). METHODS: In the electrophysiologic study four diagnostic catheters were used, including one duodecapolar for mapping the tricuspid annulus. In the patients who presented with sinus rhythm, atrial flutter was induced with programmed atrial stimulation, and then the atrial activation circuit was mapped. To demonstrate the entrainment phenomenon the IVC-TA isthmus was over-stimulated, to prove that this was the slow zone of the circuit. The radiofrequency energy was applied in the IVC-TA isthmus with the Medtronic Cosio-Fluttr ablation catheter, for 60 sec per application, with temperature control and with a maximum energy output of 50 W. Criteria for success were not only the disappearance of the atrial flutter during the application of radiofrequency energy, but also the demonstration of bi-directional IVC-TA isthmus block. RESULTS: The primary success rate was 100%. The mean procedure time was 110 +/- 22 min, mean fluoroscopy time was 23 +/- 4 min and the number of radiofrequency energy pulses was 9 +/- 3. There were no complications. The patients were followed for a mean time of 8 +/- 4 months and atrial flutter recurred in only one patient (8%). CONCLUSIONS: Atrial flutter ablation with the new Medtronic Cosio-Fluttr catheter, specially designed for the application of radiofrequency at the IVC-TA isthmus, is a safe procedure and has a high success rate. It simplifies ablation, decreasing the number of radiofrequency energy pulses, without using long sheaths and keeping short procedure and fluoroscopy times.

[Deciding about pacing mode in sinus node dysfunction: should carotid sinus massage be performed and in which circumstances?]. / Decisão do modo de pacing na doença do nódulo sinusal: será a massagem do seio carotídeo pertinente e em que circunstâncias?

OBJECTIVE: To state the incidence of carotid sinus syndrome (CSS) with atrioventricular node manifestation in patients with sinus node dysfunction (SND) and indication for a definitive pacemaker (PM), we propose a new protocol between atrial pacing AAI and double chamber DDD. POPULATION AND METHODS: 69 patients (PTS) (male 71%), median age 65 +/- 10 years, with SND (normal PQ and no intraventricular conduction defect), that had a PM implant following the protocol that included carotid sinus massage for the pacing decision, were followed prospectively between December 1995 and November 1999. During the protocol we implanted DDD PM in PTS with Wenckebach less than 130 or Wenckebach equal/over 130 and CSS. At least, in PTS with Wenckebach equal/over 130 and no CSS we implanted AAI PM. The follow-up was between 4 months and 4 years, with clinical evaluation in the first and fourth months and then half yearly, with carotid sinus massage in the first evaluation. RESULTS: About 1/4 of the 69 patients followed had SND without carotid sinus syndrome, or atrioventricular node repercussion; the SND involved the atrioventricular node in 56% of the patients, and there was a relation between the SND and carotid sinus syndrome in 18.8%. The follow-up revealed, in all patients, a complete remission of the symptoms, and when we repeated the carotid sinus massage in the first evaluation, there was a response like in the surgery room, in all patients. CONCLUSIONS: There is a significant number of patients with SND and carotid sinus syndrome. The carotid sinus massage performed in the surgery room does not influence the test sensitivity and specificity in the diagnosis of carotid sinus syndrome. The authors think that carotid sinus massage should be considered in the protocol that defines the pacing mode, in patients with SND, and that influence the choice of pacemaker in 18.8% of patients.

PML-RARA fusion transcripts in irradiated and normal hematopoietic cells.

It is believed that two important factors in the genesis of reciprocal chromosomal translocations in malignant cells are the physical proximity of the involved regions and local structural features of the chromatin fiber that make them more susceptible to breakage and rearrangement. In this work we sought to investigate whether PML-RARA fusion transcripts, characteristic of acute promyelocytic leukemia (APL), could be induced by a clastogenic agent in cells known to have, a priori, a favorable spatial distribution of these genes. A lymphoid-cell line, lacking the t(15;17) but having the PML and RARA genes in close proximity in specific phases of the cell cycle, was irradiated with 10 Gy of (60)Co, and the incidence of PML-RARA transcripts was analyzed by a highly sensitive PCR assay. Despite gene proximity, typical PML-RARA transcripts were only rarely detected in irradiated cells. The same phenomenon was observed at similar frequency in control non-irradiated cells. These findings made us investigate whether such transcripts could also be detected in peripheral blood cells from normal individuals. PML-RARA transcripts were observed at low frequencies in isolated lymphoid and granulocytic cell populations, with similar incidence in both cell types. The data thus indicate that the PML and RARA genes are not particularly susceptible to the clastogenic effects of gamma-irradiation, and that, similar to what has been reported for other chromosomal translocations, transcriptionally active PML-RARA rearrangements can be generated in normal hematopoietic cells of different lineages without apparent oncogenic consequences.

Spatial associations of centromeres in the nuclei of hematopoietic cells: evidence for cell-type-specific organizational patterns.

It is believed that the 3-dimensional organization of centromeric heterochromatin in interphase may be of functional relevance as an epigenetic mechanism for the regulation of gene expression. Accordingly, a likely possibility is that the centromeres that spatially associate into the heterochromatic structures (chromocenters) observed in the G1 phase of the cell cycle will differ in different cells. We sought to address this issue using, as a model, the chromocenters observed in quiescent normal human hematopoietic cells and primary fibroblasts. To do this, we analyzed the spatial relationships among different human centromeres in 3-D preserved cells using nonisotopic in situ hybridization and confocal microscopy. We showed quantitatively that chromocenters in all cell types do indeed represent nonrandom spatial associations of certain centromeres. Furthermore, the observed patterns of centromere association indicate that the chromocenters in these cell types are made of different combinations of specific centromeres, that hematopoietic cells are strikingly different from fibroblasts as to the composition of their chromocenters and that centromeres in peripheral blood cells appear to aggregate into distinct "myeloid" (present in monocytes and granulocytes) and "lymphoid" (present in lymphocytes) spatial patterns. These findings support the idea that the chromocenters formed in the nucleus of quiescent hematopoietic cells might represent heterochromatic nuclear compartments involved in the regulation of cell-type-specific gene expression, further suggesting that the spatial arrangement of centromeric heterochromatin in interphase is ontogenically determined during hematopoietic differentiation. (Blood. 2000;95:1608-1615)

Microwave ablation of atrial flutter.

Radiofrequency (RF) ablation of the isthmus between the inferior vena cava and the tricuspid ring has proven to be a safe and successful method of treating atrial flutter (AF). However, RF ablation lesions are small in size requiring a considerable number of energy applications to ablate the AF circuit. The aim of this study was to evaluate the feasibility and efficacy of microwave energy for AF ablation. We report a case of sustained typical AF treated successfully and safely by 1 pulse of microwave (MW) energy. This showed it is possible to treat AF with a small number of pulse applications.

Surgery for atrial fibrillation using radiofrequency catheter ablation: assessment of results at one year.

OBJECTIVE: The results obtained in 43 patients using direct intraoperative radiofrequency catheter ablation, as an alternative to surgical incisions, to perform atrial fibrillation surgery, are presented. METHODS: Forty-three patients with ages ranging from 43 to 74 years (x = 59), with chronic atrial fibrillation with an average duration 6+/-5 years were operated. Eleven patients suffered from clinically relevant tachyarrythmia and eight had previous thromboembolic events. All but one patient had concomitant mitral valve surgery. Direct intraoperative radiofrequency catheter ablation was used to perform endocardial bilateral isolation of the pulmonary veins from the left atrium. RESULTS: There were no local or general complications, namely bleeding or thromboembolic events. Of the 33 patients with more than 3 months of follow-up, 36% remained in atrial fibrillation (Santa Cruz score 0); 30% had Score 4; 18% had Score 3; 6% had Score 2; 9% had Score 1. CONCLUSIONS: We conclude that the use of intraoperative radiofrequency catheter ablation is fast and safe. Presently, this is our method of choice for surgical treatment of atrial fibrillation in mitral patients.

[The Brugada syndrome--a clinical case]. / Síndrome de Brugada--caso clínico.

A case report of a patient with syncope and family history of sudden death is presented. The precordial recordings in the standard 12-lead ECG showed a right bundle-branch block pattern with persistent ST elevation in V1 and V2-V3. After a thorough evaluation, we found no underlying organic cardiomyopathy. The diagnosis of symptomatic Brugada syndrome was made. A cardioverter-defibrillator was implanted.

[From the genotype to the phenotype]. / Do genótipo ao fenótipo.

The growing knowledge of the molecular anatomy of the human genome and the mechanisms of the gene expression, together with recent advances in molecular epidemiology, have nurtured an entirely different view of the complex relationships between genes and phenotype. This review begins with a brief description of the different types of molecular lesion that may occur in a particular gene sequence as well as the biological consequences that they originate. Then, a "molecular view" of various concepts of classical genetics is presented: dominance and recessiveness are discussed as a problem of cellular homeostasis whereas gene penetrance and expressivity are viewed as problems of variability, gene connectivity and functional pleiotropism. Based on these concepts a few final remarks focus on the relationship between genes and the environment and its enormous impact in the genesis of polygenic and multifactorial disorders.

The nuclear topography of ABL, BCR, PML, and RARalpha genes: evidence for gene proximity in specific phases of the cell cycle and stages of hematopoietic differentiation.

The mechanisms whereby chromosomal translocations are consistently associated with specific tumor types are largely unknown. A generally accepted hypothesis is that the physical proximity of the involved chromosomal regions may be one important factor in the genesis of these phenomena. Accordingly, a likely possibility is that such a proximity may occur in a cell-lineage and cell-differentiation stage-specific manner. In this work, we have addressed this issue using as models the ABL and BCR genes of t(9;22) and the PML and RARalpha genes of t(15;17). By using in situ hybridization and confocal microscopy, we have measured the distances between these two pairs of genes in three-dimensionally preserved hematopoietic cells belonging to different cell lineages, at various stages of differentiation, and at various stages of the cell cycle, with the following results. (1) Intergenic distances vary periodically during the cell cycle and a significant association of ABL with BCR and of PML with RARalpha is seen at the transition between S and G2, which persists during G2 and prophase (such a behavior is not observed for distances between ABL or PML and the beta-globin genes, used as a control). (2) The proportion of cells in which PML and RARalpha or ABL and BCR are closely associated is higher in hematopoietic precursors than in B-lymphoid cells (whereas the distances between ABL or PML and the beta-globin genes are not affected by cell type). (3) When intergenic distances in unstimulated bone marrow CD34(+) cells were compared with those in CD34(+) cells treated with interleukin-3 (IL-3), a trend towards a higher proximity of the ABL and BCR genes in the former and of the PML and RARalpha genes in the latter is observed. (4) Analysis of B-lymphoid cells during mitosis shows that intergenic distances at metaphase are strongly influenced by physical constraints imposed by the chromosomal location of the gene, by the size of the respective chromosome, and by the geometry of the metaphase plate. These findings suggest that intrinsic spatial dynamics, established early in hematopoiesis and perpetuated differentially in distinct cell lineages, may facilitate the collision of individual genes and thus reciprocal recombination between them at subsequent stages of hematopoietic differentiation.

[Role of auxiliary diagnostic tests in the clarification of the etiology of syncope: experience at an arrhythmia center]. / Papel dos exames auxiliares de diagnóstico no esclarecimento etiológico da síncope--experiência de uma consulta de arritmologia.

UNLABELLED: Syncope is a syndrome caused by a reversible reduction of blood to the brain. Three hemodynamic abnormalities can cause syncope: an acute decrease in cardiac output, an acute increase in cerebrovascular resistance and a fall in systemic blood pressure due to ineffective control of peripheral vascular resistance. We made a retrospective study of 121 patients with syncope history, 67 males, and 57 females, with mean age 48 +/- 14 years, and at least six months of clinical follow-up. Twelve patients had valvular disease, two patients had hypertrophic cardiomyopathy, eight patients had dilated cardiomyopathy, 14 patients had ischemic disease, three patients had congenital disease; 82 patients did not have cardiac disease. Syncope etiology was arrhythmic in 69 patients: 47 patients had tachyarrhythmia (supraventricular--in 27 patients and ventricular in 20 patients) and 15 patients had bradyarrhythmia (seven patients had sinus node disease and eight patients had atrioventricular block). Non arrhythmic etiology of syncope was identified in 29 patients (neurologic disease--ten patients, metabolic disease--one patient and iatrogenic--two patients; vasodepressor syncope--14 patients, and hypertrophic cardiomyopathy--two patients). It was not possible to determine the syncope etiology in 30 patients. The assessment of patients who present syncope depends on establishing the basis for the symptoms. The initial step is differentiating patients with normal cardiovascular systems from those with heart disease. In the former, tilt-table testing proved to be the most productive from a diagnostic perspective; in the latter group, electrophysiologic evaluation was the most elucidative from a diagnostic perspective. The ultimate goal is to obtain a sufficiently strong correlation between syncopal symptoms and detected abnormalities to permit an accurate assessment of prognosis and to develop an effective treatment plan. CONCLUSIONS: It is very important to establish the etiology of syncope for optimal management of patients and it is therefore possible to control the symptoms in the majority of them. The patients who present syncope require a complete history and a physical examination for an appropriate workup to be initiated. Tilt-table testing was the most accurate for the diagnosis of vasodepressor syncope while electrophysiologic testing provides an accurate method for assessing the etiology of tachyarrhythmic syncope.

[Syncope in a patient with Ebstein's anomaly and Wolff-Parkinson-White syndrome]. / Síncope em doente com anomalia de Ebstein e síndrome de Wolff-Parkinson-White.

We describe a clinical case of a patient with Ebstein's anomaly and syncope in Wolff-Parkinson-White's syndrome. After a radiofrequency ablation of an accessory atrioventricular pathway there was a different arrhythmia of ventricular origin. Although we have some doubts about their clinical relevance, we discuss the complex arrhythmic background, the medical management difficulties and the prognostic issues. There is an evaluation about ablation usefulness in this context regarding future attitudes in relation to other kinds of rhythm disorder.

A refined localization of two deleted regions in chromosome 6q associated with salivary gland carcinomas.

Deletions within chromosome 6 (6q25 to 6qter) are the most consistent structural change observed in salivary gland carcinomas. To better define the location of these deletions we investigated loss of heterozygosity (LOH) for 23 polymorphic markers within 19 salivary gland carcinomas covering several histological subtypes. LOH was observed in 47% of tumors, confirming previous reports that such losses are frequent and occur in almost all histological subtypes of tumors. The highest frequency of LOH was found at, or distal to, D6S437. Seven tumors had allelic losses for D6S297 and/or D6S37. A second peak of loss was also observed at D6S262 and D6S32. In some tumors we observed LOH in one or the other of these two regions. In other tumors we observed loss of both regions with retention of intervening loci. These data suggest that two small deletions commonly occur, one between D6S262 and D6S32 (estimated to cover less than 1.5 Mb) and another between D6S297 and D6S446 (estimated to cover approximately 2 Mb). These results extend previous studies by sublocalizing the regions of LOH and suggest that inactivation of one or more tumor suppressor genes located in these regions may be an important step in salivary gland carcinogenesis.

The spatial distribution of human immunoglobulin genes within the nucleus: evidence for gene topography independent of cell type and transcriptional activity.

The three-dimensional positioning of immunoglobulin (Ig) genes within the nucleus of human cells was investigated using in situ hybridization and confocal microscopy. The visualization of heavy and light chain genes in B-lymphoid cells showed that the three Ig genes are differentially and nonrandomly distributed in different nuclear subvolumes: the kappa genes were found to be preferentially confined to an outer nuclear volume, whereas the gamma and lambda genes consistently occupied more central positions within the nucleus, the lambda genes being more interior when compared with the gamma genes. The data further show that these overall topographical distributions are independent of gene transcriptional activity and are conserved in different cell types. Although subtle gene movements within those defined topographical regions cannot be excluded by this study, the results indicate that tissue specificity of gene expression is not accompanied by drastic changes in gene nuclear topography, rather suggesting that gene organization within the nucleus may be primarily dependent on structural constraints imposed on the respective chromosomes.

[Catheter ablation with radiofrequency energy in 100 patients with Wolff-Parkinson-White syndrome]. / Ablação por cateter com energia de radiofrequência de 100 doentes com síndrome de Wolff-Parkinson-White.

OBJECTIVE: The aim of this paper was to evaluate our results of radiofrequency catheter ablation (RFCA) of accessory pathways in patients with WPW syndrome. STUDY PATIENTS: We studied 100 consecutive patients with WPW syndrome, 52 men and 48 women, mean age 37 +/- 15 years who underwent RFCA. All patients were symptomatic, with documented episodes of supraventricular tachycardia and 9% of patients had underlying cardiac disease. METHODS: The RFCA was performed without antiarrhythmic drugs in the same session of the electrophysiologic diagnosis. The location of the accessory pathway site was obtained by catheter mapping, based on the premature and/or the presence of Kent potentials. According to the location of the accessory pathway, the ablation catheter was introduced either by the femoral vein or artery with mapping of the tricuspid or mitral ring. In the first cases performed energy application was manually controlled and thereafter was temperature guided with an upper temperature limit of 70 degrees C. We considered primary success criteria the disappearance of the delta wave in the surface ECG and the absence of ventricular preexcitation under atrial pacing and after adenosine injection. Clinical success was defined as the absence of clinical recurrence of tachycardia during the follow-up period. RESULTS: The primary success rate achieved was 88%; 91% in the left free wall pathways, 100% in the right free wall and 85% in the septal pathways (antero-septal-83%; right postero-septal-76.5%; left postero-septal-92%). A second ablation procedure was performed in seven of the twelve patients with primary unsuccess obtaining a final success rate of 93% (left free wall-94.5%; septal pathways-91.6%). After a mean follow-up period of 8 +/- 7 months clinical recurrence occurred in 9% (eight patients), five of which are under anti-arrhythmic therapy (62.5%). Clinical success rate at the end of the follow-up period was 88%. CONCLUSIONS: In our experience RFCA has shown to be safe and with a high success rate in patients with symptomatic pre-excitation. In this group of patients it was an effective therapy.