Enhanced weak superconductivity in trigonalγ-PtBi2

Electrical resistivity experiments show superconductivity atTc=1.1K in a high-quality single crystal of trigonalγ-PtBi2, with an enhanced critical magnetic fieldμ0Hc2(0)≳1.5Tesla and a low critical current-densityJc(0)≈40 A cm-2atH = 0. BothTcandHc2(0)are the highest reported values for stoichiometric bulk samples at ambient pressure. We found a weakHc2anisotropy withΓ=Hc2ab/Hc2c<1, which is unusual among superconductors. Under a magnetic field, the superconducting transition becomes broader and asymmetric. Along with the low critical currents, this observation suggests an inhomogeneous superconducting state. In fact, no trace of superconductivity is observed through field-cooling-zero-field-cooling magnetization experiments.

Association between common cardiovascular risk factors and clinical phenotype in patients with hypertrophic cardiomyopathy from the European Society of Cardiology (ESC) EurObservational Research Programme (EORP) Cardiomyopathy/Myocarditis registry

AIMS

The interaction between common cardiovascular risk factors (CVRF) and hypertrophic cardiomyopathy (HCM) is poorly studied. We sought to explore the relation between CVRF and the clinical characteristics of patients with HCM enrolled in the EURObservational Research Programme (EORP) Cardiomyopathy registry.

METHODS AND RESULTS

1739 patients with HCM were studied. The relation between hypertension (HT), diabetes (DM), body mass index (BMI), and clinical traits was analysed. Analyses were stratified according to the presence or absence of a pathogenic variant in a sarcomere gene. The prevalence of HT, DM, and obesity (Ob) was 37, 10, and 21%, respectively. HT, DM, and Ob were associated with older age (P<0.001), less family history of HCM (HT and DM P<0.001), higher New York Heart Association (NYHA) class (P<0.001), atrial fibrillation (HT and DM P<0.001; Ob p = 0.03) and LV (left ventricular) diastolic dysfunction (HT and Ob P<0.001; DM P = 0.003). Stroke was more frequent in HT (P<0.001) and mutation-positive patients with DM (P = 0.02). HT and Ob were associated with higher provocable LV outflow tract gradients (HT P<0.001, Ob P = 0.036). LV hypertrophy was more severe in Ob (P = 0.018). HT and Ob were independently associated with NYHA class (OR 1.419, P = 0.017 and OR 1.584, P = 0.004, respectively). Other associations, including a higher proportion of females in HT and of systolic dysfunction in HT and Ob, were observed only in mutation-positive patients.

CONCLUSION

Common CVRF are associated with a more severe HCM phenotype, suggesting a proactive management of CVRF should be promoted. An interaction between genotype and CVRF was observed for some traits.

The role of the electrocardiographic phenotype in risk stratification for sudden cardiac death in childhood hypertrophic cardiomyopathy

AIMS

The 12-lead electrocardiogram (ECG) is routinely performed in children with hypertrophic cardiomyopathy (HCM). An ECG risk score has been suggested as a useful tool for risk stratification, but this has not been independently validated. This aim of this study was to describe the ECG phenotype of childhood HCM in a large, international, multi-centre cohort and investigate its role in risk prediction for arrhythmic events.

METHODS AND RESULTS

Data from 356 childhood HCM patients with a mean age of 10.1 years (±4.5) were collected from a retrospective, multi-centre international cohort. Three hundred and forty-seven (97.5%) patients had ECG abnormalities at baseline, most commonly repolarization abnormalities (n = 277, 77.8%); left ventricular hypertrophy (n = 240, 67.7%); abnormal QRS axis (n = 126, 35.4%); or QT prolongation (n = 131, 36.8%). Over a median follow-up of 3.9 years (interquartile range 2.0-7.7), 25 (7%) had an arrhythmic event, with an overall annual event rate of 1.38 (95% CI 0.93-2.04). No ECG variables were associated with 5-year arrhythmic event on univariable or multivariable analysis. The ECG risk score threshold of >5 had modest discriminatory ability [C-index 0.60 (95% CI 0.484-0.715)], with corresponding negative and positive predictive values of 96.7% and 6.7.

CONCLUSION

In a large, international, multi-centre cohort of childhood HCM, ECG abnormalities were common and varied. No ECG characteristic, either in isolation or combined in the previously described ECG risk score, was associated with 5-year sudden cardiac death risk. This suggests that the role of baseline ECG phenotype in improving risk stratification in childhood HCM is limited.

Novel device for simultaneous volumetric and x-ray diffraction measurements on metal-hydrogen systems

Hydrogen storage materials can form more than one hydride phase. These different phases, in turn, display different hydrogen absorption/desorption capacities, kinetics, and stabilities. Studies aimed at characterizing and improving these materials usually need to correlate hydrogen intake with the precise determination of the hydride phase involved in the process. Here, we present a device designed to perform measurements of well known volumetric techniques with simultaneous x-ray diffraction on the material under study. The compact design can stand up to 6000 kPa of internal pressure while the sample can be heated up to 450 degrees C. The design process was assisted by finite element modeling and by the use of mock-up prototypes in order to optimize the thermal and under load behaviors. We provide two examples of use for this new device: (1) hydride decomposition in LaNi5 at 115 degrees C and (2) formation of MgCo during the programmed thermal desorption of the Mg2CoH5 hydride.

Equipment for hydrogen absorption-desorption cycling characterization of hydride forming materials

Hydrogen storage materials suffer different degradation processes when they are cycled, forming and decomposing their associated hydride phases. In order to study these processes, we have designed and built an automated apparatus specifically developed for cycling samples of hydride forming materials by changing the external hydrogen pressure. Instead of the standard open configuration involving a high-pressure, high-quality gas bottle and a vacuum pump, the equipment uses another hydride forming material (in our case LaNi5) as a source and sink of hydrogen. The resulting closed-loop configuration eliminates hydrogen waste and ensures that extremely high purity gas is used during the whole experiment, thanks to the purifying properties of the selected hydride as source/sink. Hydrogen pressure is set by changing the source/sink temperature. Cycles can be performed as fast as one cycle every 5 min, a period comparable with typical good hydride forming material kinetics. An example of application of the apparatus is given for 1000 absorption/ desorption cycles on a Mm0.8Ca0.2Ni5 sample.

[Congenital absence of the inferior vena cava as a risk factor for pulmonar thromboembolism]

The absence of the inferior vena cava is a rare congenital anomaly. Currently its diagnosis is based on non-invasive imaging techniques (computerised axial tomagraphy and nuclear magnetic resonance). In most cases, it constitutes a casual finding upon practising these image tests unrelated to this congenital anomaly. In the symptomatic patients, the complaints associated are secondary to venous insufficiency and/or deep vein thrombosis. Recently the congenital absence of inferior vena cava has been described as a risk factor of deep vein thrombosis in young patients. We present a case of congenital absence of inferior vena cava that was admitted in our hospital because of pulmonary thromboembolism.

Early detection of nonresponse to interferon plus ribavirin combination treatment of chronic hepatitis C

We have investigated the value of early hepatitis C virus (HCV) RNA decline (DeltaHCV RNA) to predict response to combination therapy in 66 chronic hepatitis C patients treated with IFN-alpha2b (3 MU thrice weekly) and ribavirin (800 mg daily) for 12 months [25 sustained responders (SR) and 41 nonresponders or relapsers (NR)]. Serum HCV RNA was retrospectively measured in samples obtained at baseline and 4, 8 and 12 weeks after treatment onset, using a commercially available quantitative RT-PCR assay. At 4 weeks, serum HCV RNA had decreased a mean of 2.6 +/- 0.8 logs among SR as compared with only 0.5 +/- 0.8 logs in NR (P < 0.001), and was already undetectable (< 600 IU/mL) in 12 (48%) of the SR but in none of the NR. At 8 weeks, HCV RNA was undetectable in 21 SR and in 2 NR and mean DeltaHCV RNA were 4.2 +/- 1.3 and 0.8 +/- 1.0 logs, respectively (P < 0.001). At week 12 all SR had undetectable HCV RNA as compared with only five NR (P < 0.001). Stepwise logistic regression analysis identified DeltaHCV RNA at 12 weeks as the strongest predictor of sustained response. Receiver operating characteristic (ROC) curves of DeltaHCV RNA for sustained response prediction identified sensitivity peaks with 100% negative predictive value corresponding to DeltaHCV RNA > 1 log at 4 weeks, > 2 logs at 8 weeks and > 3 logs at 12 weeks. Our results show that early changes in the HCV RNA level may reliably identify patients having no chance of a sustained virological response during the first 3 months of combination therapy, thus providing an excellent tool for optimizing antiviral treatment of chronic hepatitis C.

[Coarctation of the abdominal aorta. Treatment by stent placement]

We report a nine-year-old boy referred for evaluation of suspected coarctation of the aorta. He presented with hypertension and absent femoral pulses. A 50 mmHg gradient was detected in the abdominal aorta by color flow doppler echocardiography but the level of coarctation was impossible to locate. The diagnosis was made by magnetic resonance imaging and aortography, showing segmentary hypoplasia in the upper abdominal segment of the descending aorta, immediately below the celiac axis and above the renal arteries. Treatment consisted in placement of a stent Palmaz, which was effective in significantly decreasing the gradient. Some clinical aspects and different therapeutic strategies for this unusual case are discussed.

Experimental evidence of stochastic resonance without tuning due to non-Gaussian noises

In order to test theoretical predictions, we have studied the phenomenon of stochastic resonance in an electronic experimental system driven by white non-Gaussian noise. In agreement with the theoretical predictions our main findings are an enhancement of the sensibility of the system together with a remarkable widening of the response (robustness). This implies that even a single resonant unit can reach a marked reduction in the need for noise tuning.

[Influential factors in mortality rate from congenital heart disease. Study of 1,216 children in the Autonomous Community of Murcia (1978-1990)]

INTRODUCTION

In the last few years, important progress has taken place in management of congenital heart disease. These changes have had an influence on diagnosis, preoperative management, surgery treatment and postoperative care, giving rise to better results in the treatment of children suffering from congenital heart disease.

AIM

To assess the results of congenital heart diseases in a reference hospital by comparing two periods with reference to both diagnosis and therapeutical management. We also intend to investigate the influence that factors such as the existence of extracardiac congenital malformations and heart surgery have on mortality.

PATIENTS AND METHODS

Our sample group was made up of 1,216 children suffering from congenital heart disease. Their ages ranged from 1 day to 7 years old. These children were born over a period of thirteen years and studied at the paediatric cardiology unit in a reference hospital in the Autonomous Community of Murcia, a region of Spain. We retrospectively analysed their development by individual heart diseases (and their associated factors), and the global results. Our research was divided into two periods: between 1978 and 1983, and between 1984 and 1990. Differences were found regarding diagnosis and treatment.

RESULTS

a) Mortality rate from congenital heart disease decreased in the period between 1984 and 1990 in comparison to the period between 1978 and 1983, from 28 to 21,7% (p < 0.05); b) individually, the mortality rate decreased with statistical significance in two diseases: interventricular communication and patent ductus arteriosus, and c) there is a higher mortality rate of patients with no surgery treatment and/or extracardiac malformations.

CONCLUSION

Progress in the management of congenital heart disease has led to a more favourable outcome in the last years.

Evaluation of hepatitis C virus RNA RT/PCR qualitative and quantitative second generation assays

Hepatitis C virus (HCV) RNA qualitative and quantitative second generation assays (Amplicor HCV v2.0 and Amplicor HCV Monitor v2.0, respectively) were evaluated by testing serum samples from 132 blood donors anti-HCV positive HCV RNA negative by first generation qualitative assay and 326 viremic patients. An HCV RNA transcript was synthesized and ten-fold dilutions were used to assess sensitivity. Second generation assays were one log more sensitive than their respective first generation tests (10(2) copies per ml vs. 10(3) for the qualitative tests; 10(3) copies per ml vs. 10(4) for the quantitative tests). From the 132 anti-HCV positive RNA negative subjects, 6 (5%) were positive by Amplicor v2.0. Quantification figures by Monitor v2.0 were similar in genotypes 1, 2 and 3, whereas Monitor 1.0 values were higher in genotype 1 than in genotype 2 or 3. In 114 patients, branched-DNA v2.0 obtained higher values than Monitor v2.0 and Monitor v1.0 (6.6+/-0.6 log RNA copies per ml, 6.4+/-0.6, and 5.3+/-0.7, respectively, P<0.001). HCV RNA qualitative and quantitative second generation assays are more sensitive and genotype independent than first generation assays.

Utility of early testing for HCV viremia as predictive factor of sustained response during interferon or interferon plus ribavirin treatment

BACKGROUND/AIM

To evaluate the utility of early testing for hepatitis C viremia as a predictor of treatment outcome during interferon or combination therapy.

METHODS

We studied 184 patients with chronic hepatitis C who received interferon and were monitored for HCV RNA. Sixty-two patients received interferon alone for 12 months and 122 patients, who were still HCV RNA positive at 2 months, received an additional 12-month course of interferon and ribavirin combination therapy.

RESULTS

Using this strategy, sustained response occurred in a total of 34 patients (18.5%). Independent variables associated with sustained response were HCV genotype (p=0.06), viral load < or = 5.1 logs/ml (p= 0.005) and negative HCV RNA at 1 month (p<0.0001) in the interferon group, and female sex (p=0.04), genotype (p=0.03), viral load < or = 5.5 logs/ml (p=0.01), normal ALT (p=0.001) and decline in viral load > or = 1.2 logs/ml after 2 months of interferon monotherapy (p<0.001) and negative viremia at 5 months of ribavirin onset (p<0.0001) in the combination therapy group. Persistence of viremia at 1 month of interferon monotherapy and at 5 months of combination therapy were the strongest predictors of non-response (negative predictive value of 100% and 99%, respectively).

CONCLUSIONS

Qualitative assessment of HCV RNA during treatment is the strongest predictor of sustained response during interferon or combination therapy for chronic hepatitis C.

Application of isotope-selective non-dispersive infrared spectrometry for the evaluation of the 13C-urea breath test: comparison with three concordant methods

The aim of this work was to compare the performance of isotope-selective non-dispersive infrared spectrometry (IRIS) for the 13C-urea breath test with the combination of the 14C-urea breath test (14C-UBT), urease test and histologic examination for the diagnosis of H. pylori (HP) infection. Fifty-three duodenal ulcer patients were studied. All patients were submitted to gastroscopy to detect HP by the urease test, histologic examination and 14C-UBT. To be included in the study the results of the 3 tests had to be concordant. Within one month after admission to the study the patients were submitted to IRIS with breath samples collected before and 30 min after the ingestion of 75 mg 13C-urea dissolved in 200 ml of orange juice. The samples were mailed and analyzed 11.5 (4-21) days after collection. Data were analyzed statistically by the chi-square and Mann-Whitney test and by the Spearman correlation coefficient. Twenty-six patients were HP positive and 27 negative. There was 100% agreement between the IRIS results and the HP status determined by the other three methods. Using a cutoff value of delta-over-baseline (DOB) above 4.0 the IRIS showed a mean value of 19.38 (minimum = 4.2, maximum = 41.3, SD = 10.9) for HP-positive patients and a mean value of 0.88 (minimum = 0.10, maximum = 2.5, SD = 0.71) for negative patients. Using a cutoff value corresponding to 0.800% CO2/weight (kg), the 14C-UBT showed a mean value of 2.78 (minimum = 0.89, maximum = 5.22, SD = 1.18) in HP-positive patients. HP-negative patients showed a mean value of 0.37 (minimum = 0.13, maximum = 0.77, SD = 0.17). IRIS is a low-cost, easy to manage, highly sensitive and specific test for H. pylori detection. Storing and mailing the samples did not interfere with the performance of the test.

Cardiovascular involvement in a boy with Sweet's syndrome

Acute febrile neutrophilic dermatosis (Sweet's syndrome) is a rare disease in infancy. It may present in an isolated manner or be associated with diverse conditions. Only two children with postinflammatory slack skin who developed cardiovascular disease have been described to date, both of whom died from coronary artery occlusion. We report a boy with Sweet's syndrome and diffuse vascular disease involving the aorta and the supraaortic vessels, the pulmonary trunk, and the right coronary artery but without signs of coronary obstruction.

Epidemiological and clinical aspects of hepatitis C virus infection in the Russian Republic of Daghestan

Hepatitis C virus (HCV) is a leading cause of chronic liver disease. The prevalence in blood donors in the USA and West Europe is around 0.3%. However, there are few studies performed in East Europe. We have studied the prevalence of hepatitis C virus infection and risk factors associated with it in the Russian Republic of Daghestan.

POPULATION AND METHODS

We included 10,682 volunteer blood donors, 267 commercial blood donors, 97 high risk patients (22 haemophiliacs, 41 in haemodialysis program and 34 parenteral drug addicts), and 87 patients with chronic liver disease (61 chronic hepatitis, 20 cirrhosis and 6 hepatocellular carcinoma). Antibodies against HCV were detected by second generation ELISA.

RESULTS

0.93% of volunteer blood donors were found to be HCV reactive. Factors with stronger association with seropositivity were previous blood transfusion and parenteral drug addiction. 66% of seropositive blood donors had an elevated level of ALT. Alcohol use correlated with more marked deterioration in liver function tests. 7.5% of commercial blood donors were seropositive. Prevalence in high risk patients and in patients with chronic liver disease was very high (50-80% and 40-50%, respectively).

CONCLUSION

The Russian Republic of Daghestan has one of the lowest rates of HCV infection in East Europe. Commercial blood donors have a very high prevalence of HCV infection. The risk factors associated with HCV infection are similar to those found in other epidemiological studies.

Prophylactic intravenous ondansetron in patients undergoing cataract extraction under general anesthesia

During the past decade the demand for outpatient surgery has grown rapidly. Postoperative nausea and vomiting is one of the more common undesirable consequences of surgery, which may significantly delay the patient's discharge from the ambulatory surgery center. None of the currently used antiemetic drugs is considered totally effective in abolishing nausea or vomiting. The purpose of this study was to compare the efficacy of ondansetron, a highly selective 5-hydroxytryptamine subtype-3 receptor antagonist, with that of metoclopramide for the prevention of postoperative emesis in patients undergoing cataract surgery. The incidence of postoperative nausea was significantly less in the ondansetron group than that in the metoclopramide group (p = 0.046). Although the incidence of vomiting was clinically less frequent in the ondansetron group, there were no significant differences between both treatment groups. To our knowledge, this is the first study to demonstrate that ondansetron is effective to prevent postoperative emesis after extracapsular cataract extraction.

[Aortic insufficiency secondary to an unruptured congenital aneurysm of the sinus of Valsalva]

Congenital aneurysm of the sinus of Valsalva is an uncommon entity. Its diagnosis is rare in infancy because most cases are asymptomatic. This condition is usually detected in adults as incidental finding or a complication due to aneurysm. We report a five-year-old asymptomatic child, with a congenital unruptured aneurysm of the right sinus of Valsalva. It was diagnosed on two-dimensional and Doppler echocardiography, and confirmed by angiography showing an aortic regurgitation. The aim of this publications is to report another case of this rare condition in pediatric cardiology, which real importance is probably subestimated because of unusual clinical manifestation. Nevertheless, the increasing use of the two-dimensional and Doppler echocardiography will provide much more cases of this entity. Diagnosis and treatment are reviewed as well as bibliography.

Treatment of duodenal ulcer with omeprazole or ranitidine in a Brazilian population: a multicenter double-blind, parallel group study

Two hundred and forty-one patients with at least one ulcer at stage A1 or A2, measuring at least 5 mm in its larger diameter, were included in this Brazilian double-blind randomized study. Patients received omeprazole 20 mg in the morning (n = 120) or ranitidine 300 mg at night (n = 121) for 2 wk; unhealed ulcers were treated for an additional 2 wk. At the end of 4 wk, unhealed ulcers were treated openly with omeprazole 20 mg o.m. for 4 wk. Healing rates at 2 and 4 wk were 67.3% and 92.9% for omeprazole and 39.8% and 82.0% for ranitidine (per protocol analysis). Results were similar when analyzed as intention to treat (p significant in favor of omeprazole). Epigastric day-time pain was the most common of all symptoms (89.2%), but only heartburn at day 15 showed a significantly better response to omeprazole than to ranitidine. A multivariate analysis (logit analysis) showed that the odds in favor of healing were greater for small ulcers, nonsmokers, and omeprazole treatment.