The genome of black cottonwood, Populus trichocarpa (Torr. & Gray)

We report the draft genome of the black cottonwood tree, Populus trichocarpa. Integration of shotgun sequence assembly with genetic mapping enabled chromosome-scale reconstruction of the genome. More than 45,000 putative protein-coding genes were identified. Analysis of the assembled genome revealed a whole-genome duplication event; about 8000 pairs of duplicated genes from that event survived in the Populus genome. A second, older duplication event is indistinguishably coincident with the divergence of the Populus and Arabidopsis lineages. Nucleotide substitution, tandem gene duplication, and gross chromosomal rearrangement appear to proceed substantially more slowly in Populus than in Arabidopsis. Populus has more protein-coding genes than Arabidopsis, ranging on average from 1.4 to 1.6 putative Populus homologs for each Arabidopsis gene. However, the relative frequency of protein domains in the two genomes is similar. Overrepresented exceptions in Populus include genes associated with lignocellulosic wall biosynthesis, meristem development, disease resistance, and metabolite transport.

A physical map of the human genome

The human genome is by far the largest genome to be sequenced, and its size and complexity present many challenges for sequence assembly. The International Human Genome Sequencing Consortium constructed a map of the whole genome to enable the selection of clones for sequencing and for the accurate assembly of the genome sequence. Here we report the construction of the whole-genome bacterial artificial chromosome (BAC) map and its integration with previous landmark maps and information from mapping efforts focused on specific chromosomal regions. We also describe the integration of sequence data with the map.

Melatonin: a peroxyl radical scavenger more effective than vitamin E

We have compared the peroxyl radical scavenger ability to melatonin with that of vitamin E, vitamin C and reduced glutathione (GSH). In the assay system, beta-phycoerythrin (beta-PE) was used as fluorescent indicator protein, 2-2'-azo-bis(2-amidinopropane)dihydrochloride as a peroxyl radical generator and the water soluble vitamin E analogue. Trolox, as reference standard. Results are expressed as oxygen radical absorbing capacity (ORAC(perox)) units, where 1 ORAC unit equals the net protection produced by 1 microM Trolox. A linear correlation of ORAC values with concentration (0.5-4 microM) of all the substances tested has been observed. However, on molar basis, the relative ORAC(perox) of Trolox, vitamin C, GSH and melatonin was 1:1.12:0:68:2.04, respectively. Thus, melatonin, which is a lipid-soluble compound, was twice more active than vitamin E, believed to be the most effective lipophilic antioxidant.

Arrhythmic Mitral Valve Prolapse and Sudden Cardiac Death

BACKGROUND

Mitral valve prolapse (MVP) may present with ventricular arrhythmias and sudden cardiac death (SCD) even in the absence of hemodynamic impairment. The structural basis of ventricular electric instability remains elusive.

METHODS AND RESULTS

The cardiac pathology registry of 650 young adults (≤40 years of age) with SCD was reviewed, and cases with MVP as the only cause of SCD were re-examined. Forty-three patients with MVP (26 females; age range, 19-40 years; median, 32 years) were identified (7% of all SCD, 13% of women). Among 12 cases with available ECG, 10 (83%) had inverted T waves on inferior leads, and all had right bundle-branch block ventricular arrhythmias. A bileaflet involvement was found in 70%. Left ventricular fibrosis was detected at histology at the level of papillary muscles in all patients, and inferobasal wall in 88%. Living patients with MVP with (n=30) and without (control subjects; n=14) complex ventricular arrhythmias underwent a study protocol including contrast-enhanced cardiac magnetic resonance. Patients with either right bundle-branch block type or polymorphic complex ventricular arrhythmias (22 females; age range, 28-43 years; median, 41 years), showed a bileaflet involvement in 70% of cases. Left ventricular late enhancement was identified by contrast-enhanced cardiac magnetic resonance in 93% of patients versus 14% of control subjects (P<0.001), with a regional distribution overlapping the histopathology findings in SCD cases.

CONCLUSIONS

MVP is an underestimated cause of arrhythmic SCD, mostly in young adult women. Fibrosis of the papillary muscles and inferobasal left ventricular wall, suggesting a myocardial stretch by the prolapsing leaflet, is the structural hallmark and correlates with ventricular arrhythmias origin. Contrast-enhanced cardiac magnetic resonance may help to identify in vivo this concealed substrate for risk stratification.

Generation and analysis of 280,000 human expressed sequence tags

We report the generation of 319,311 single-pass sequencing reactions (known as expressed sequence tags, or ESTs) obtained from the 5' and 3' ends of 194,031 human cDNA clones. Our goal has been to obtain tag sequences from many different genes and to deposit these in the publicly accessible Data Base for Expressed Sequence Tags. Highly efficient automatic screening of the data allows deposition of the annotated sequences without delay. Sequences have been generated from 26 oligo(dT) primed directionally cloned libraries, of which 18 were normalized. The libraries were constructed using mRNA isolated from 17 different tissues representing three developmental states. Comparisons of a subset of our data with nonredundant human mRNA and protein data bases show that the ESTs represent many known sequences and contain many that are novel. Analysis of protein families using Hidden Markov Models confirms this observation and supports the contention that although normalization reduces significantly the relative abundance of redundant cDNA clones, it does not result in the complete removal of members of gene families.

Cardiac MR With Late Gadolinium Enhancement in Acute Myocarditis With Preserved Systolic Function: ITAMY Study

BACKGROUND

The prognostic role of cardiac magnetic resonance (CMR) and late gadolinium enhancement (LGE) has not been clarified in acute myocarditis (AM) with preserved left ventricular (LV) ejection fraction (EF).

OBJECTIVES

This study sought to evaluate the role of CMR and LGE in the prognosis of AM with preserved LVEF.

METHODS

This study analyzed data from ITAMY (ITalian multicenter study on Acute MYocarditis) and evaluated CMR results from 386 patients (299 male; mean age 35 ± 15 years) with AM and preserved LVEF. Clinical follow-up was performed for a median of 1,572 days. A clinical combined endpoint of cardiac death, appropriate implantable cardioverter-defibrillator firing, resuscitated cardiac arrest, and hospitalization for heart failure was used.

RESULTS

Among the 374 patients with suitable images, LGE involved the subepicardial layer inferior and lateral wall in 154 patients (41%; IL group), the midwall layer of the anteroseptal wall in 135 patients (36%; AS [anteroseptal] group), and other segments in 59 patients (16%; other-LGE group), and it was absent in 26 patients (no-LGE group). The AS group had a greater extent of LGE and a higher LV end-diastolic volume index than other groups, but levels of inflammatory markers were lower than in the other groups. Kaplan-Meier curve analysis indicated that the AS group had a worse prognosis than the other groups (p < 0.0001). Finally, in multivariable analysis, AS LGE was the best independent CMR predictor of the combined endpoint (odds ratio: 2.73; 95% confidence interval: 1.2 to 5.9; p = 0.01).

CONCLUSIONS

In patients with AM and preserved LVEF, LGE in the midwall layer of the AS myocardial segment is associated with a worse prognosis than other patterns of presentation.

Genetic definition and sequence analysis of Arabidopsis centromeres

High-precision genetic mapping was used to define the regions that contain centromere functions on each natural chromosome in Arabidopsis thaliana. These regions exhibited dramatic recombinational repression and contained complex DNA surrounding large arrays of 180-base pair repeats. Unexpectedly, the DNA within the centromeres was not merely structural but also encoded several expressed genes. The regions flanking the centromeres were densely populated by repetitive elements yet experienced normal levels of recombination. The genetically defined centromeres were well conserved among Arabidopsis ecotypes but displayed limited sequence homology between different chromosomes, excluding repetitive DNA. This investigation provides a platform for dissecting the role of individual sequences in centromeres in higher eukaryotes.

Morphofunctional Abnormalities of Mitral Annulus and Arrhythmic Mitral Valve Prolapse

Supplemental Digital Content is available in the text.

Background—

Arrhythmic mitral valve prolapse (MVP) is characterized by myxomatous leaflets and left ventricular (LV) fibrosis of papillary muscles and inferobasal wall. We searched for morphofunctional abnormalities of the mitral valve that could explain a regional mechanical myocardial stretch.

Methods and Results—

Thirty-six (27 female patients; median age: 44 years) arrhythmic MVP patients with LV late gadolinium enhancement on cardiac magnetic resonance and no or trivial mitral regurgitation, and 16 (6 female patients; median age: 40 years) MVP patients without LV late gadolinium enhancement were investigated by morphofunctional cardiac magnetic resonance. Mitral annulus disjunction (median: 4.8 versus 1.8 mm; P<0.001), end-systolic mitral annular diameters (median: 41.2 versus 31.5; P=0.004) and end-diastolic mitral annular diameters (median: 35.5 versus 31.5; P=0.042), prevalence of posterior systolic curling (34 [94%] versus 3 [19%]; P<0.001), and basal to mid LV wall thickness ratio >1.5 (22 [61%] versus 4 [25%]; P=0.016) were higher in MVP patients with late gadolinium enhancement than in those without. A linear correlation was found between mitral annulus disjunction and curling (R=0.85). A higher prevalence of auscultatory midsystolic click (26 [72%] versus 6 [38%]; P=0.018) was also noted. Histology of the mitral annulus showed a longer mitral annulus disjunction in 50 sudden death patients with MVP and LV fibrosis than in 20 patients without MVP (median: 3 versus 1.5 mm; P<0.001).

Conclusions—

Mitral annulus disjunction is a constant feature of arrhythmic MVP with LV fibrosis. The excessive mobility of the leaflets caused by posterior systolic curling accounts for a mechanical stretch of the inferobasal wall and papillary muscles, eventually leading to myocardial hypertrophy and scarring. These mitral annulus abnormalities, together with auscultatory midsystolic click, may identify MVP patients who would need arrhythmic risk stratification.

Sequence and analysis of chromosome 4 of the plant Arabidopsis thaliana

The higher plant Arabidopsis thaliana (Arabidopsis) is an important model for identifying plant genes and determining their function. To assist biological investigations and to define chromosome structure, a coordinated effort to sequence the Arabidopsis genome was initiated in late 1996. Here we report one of the first milestones of this project, the sequence of chromosome 4. Analysis of 17.38 megabases of unique sequence, representing about 17% of the genome, reveals 3,744 protein coding genes, 81 transfer RNAs and numerous repeat elements. Heterochromatic regions surrounding the putative centromere, which has not yet been completely sequenced, are characterized by an increased frequency of a variety of repeats, new repeats, reduced recombination, lowered gene density and lowered gene expression. Roughly 60% of the predicted protein-coding genes have been functionally characterized on the basis of their homology to known genes. Many genes encode predicted proteins that are homologous to human and Caenorhabditis elegans proteins.

Nonischemic Left Ventricular Scar as a Substrate of Life-Threatening Ventricular Arrhythmias and Sudden Cardiac Death in Competitive Athletes

Background—

The clinical profile and arrhythmic outcome of competitive athletes with isolated nonischemic left ventricular (LV) scar as evidenced by contrast-enhanced cardiac magnetic resonance remain to be elucidated.

Methods and Results—

We compared 35 athletes (80% men, age: 14–48 years) with ventricular arrhythmias and isolated LV subepicardial/midmyocardial late gadolinium enhancement (LGE) on contrast-enhanced cardiac magnetic resonance (group A) with 38 athletes with ventricular arrhythmias and no LGE (group B) and 40 healthy control athletes (group C). A stria LGE pattern with subepicardial/midmyocardial distribution, mostly involving the lateral LV wall, was found in 27 (77%) of group A versus 0 controls (group C; P<0.001), whereas a spotty pattern of LGE localized at the junction of the right ventricle to the septum was respectively observed in 11 (31%) versus 10 (25%; P=0.52). All athletes with stria pattern showed ventricular arrhythmias with a predominant right bundle branch block morphology, 13 of 27 (48%) showed ECG repolarization abnormalities, and 5 of 27 (19%) showed echocardiographic hypokinesis of the lateral LV wall. The majority of athletes with no or spotty LGE pattern had ventricular arrhythmias with a predominant left bundle branch block morphology and no ECG or echocardiographic abnormalities. During a follow-up of 38±25 months, 6 of 27 (22%) athletes with stria pattern experienced malignant arrhythmic events such as appropriate implantable cardiac defibrillator shock (n=4), sustained ventricular tachycardia (n=1), or sudden death (n=1), compared with none of athletes with no or LGE spotty pattern and controls.

Conclusions—

Isolated nonischemic LV LGE with a stria pattern may be associated with life-threatening arrhythmias and sudden death in the athlete. Because of its subepicardial/midmyocardial location, LV scar is often not detected by echocardiography.

Compound and digenic heterozygosity predicts lifetime arrhythmic outcome and sudden cardiac death in desmosomal gene-related arrhythmogenic right ventricular cardiomyopathy

BACKGROUND

Mutations in genes encoding for desmosomal proteins are the most common cause of arrhythmogenic right ventricular cardiomyopathy (ARVC). We assessed the value of genotype for prediction of lifetime major arrhythmic events and sudden cardiac death (SCD) in desmosomal gene-related ARVC.

METHODS AND RESULTS

The overall study population included 134 desmosomal gene mutation carriers (68 men; median age 36 years [22-52]) from 44 consecutive ARVC families undergoing comprehensive genetic screening. The probability of experiencing a first major arrhythmic event or SCD during a lifetime was determined by using date of birth as start point for the time-to-event analysis, and was stratified by sex, desmosomal genes, mutation types, and genotype complexity (single versus multiple mutations). One hundred thirteen patients (84%) carried a single desmosomal gene mutation in desmoplakin (n=44; 39%), plakophilin-2 (n=38; 34%), desmoglein-2 (n=30; 26%), and desmocollin-2 (n=1; 1%), whereas 21 patients (16%) had a complex genotype with compound heterozygosity in 7 and digenic heterozygosity in 14. Over a median observation period of 39 (22-52) years, 22 patients (16%) from 20 different families had arrhythmic events, such as SCD (n=1), aborted SCD because of ventricular fibrillation (n=6), sustained ventricular tachycardia (n=14), and appropriate defibrillator intervention (n=1). Multiple desmosomal gene mutations and male sex were independent predictors of lifetime arrhythmic events with a hazard ratio of 3.71 (95% confidence interval, 1.54-8.92; P=0.003) and 2.76 (95% confidence interval, 1.19-6.41; P=0.02), respectively.

CONCLUSIONS

Compound/digenic heterozygosity was identified in 16% of ARVC-causing desmosomal gene mutation carriers and was a powerful risk factor for lifetime major arrhythmic events and SCD. These results support the use of comprehensive genetic screening of desmosomal genes for arrhythmic risk stratification in ARVC.

Gemcitabine/cannabinoid combination triggers autophagy in pancreatic cancer cells through a ROS-mediated mechanism

Gemcitabine (GEM, 2′,2′-difluorodeoxycytidine) is currently used in advanced pancreatic adenocarcinoma, with a response rate of < 20%. The purpose of our work was to improve GEM activity by addition of cannabinoids. Here, we show that GEM induces both cannabinoid receptor-1 (CB1) and cannabinoid receptor-2 (CB2) receptors by an NF-κB-dependent mechanism and that its association with cannabinoids synergistically inhibits pancreatic adenocarcinoma cell growth and increases reactive oxygen species (ROS) induced by single treatments. The antiproliferative synergism is prevented by the radical scavenger N-acetyl--cysteine and by the specific NF-κB inhibitor BAY 11-7085, demonstrating that the induction of ROS by GEM/cannabinoids and of NF-κB by GEM is required for this effect. In addition, we report that neither apoptotic nor cytostatic mechanisms are responsible for the synergistic cell growth inhibition, which is strictly associated with the enhancement of endoplasmic reticulum stress and autophagic cell death. Noteworthy, the antiproliferative synergism is stronger in GEM-resistant pancreatic cancer cell lines compared with GEM-sensitive pancreatic cancer cell lines. The combined treatment strongly inhibits growth of human pancreatic tumor cells xenografted in nude mice without apparent toxic effects. These findings support a key role of the ROS-dependent activation of an autophagic program in the synergistic growth inhibition induced by GEM/cannabinoid combination in human pancreatic cancer cells.

Mitral Valve Prolapse, Ventricular Arrhythmias, and Sudden Death

Despite a 2% to 3% prevalence of echocardiographically defined mitral valve prolapse (MVP) in the general population, the actual burden, risk stratification, and treatment of the so-called arrhythmic MVP are unknown. The clinical profile is characterized by a patient, usually female, with mostly bileaflet myxomatous disease, mid-systolic click, repolarization abnormalities in the inferior leads, and complex ventricular arrhythmias with polymorphic/right bundle branch block morphology, without significant regurgitation. Among the various pathophysiologic mechanisms of electrical instability, left ventricular fibrosis in the papillary muscles and inferobasal wall, mitral annulus disjunction, and systolic curling have been recently described by pathological and cardiac magnetic resonance studies in sudden death victims and patients with arrhythmic MVP. In addition, premature ventricular beats arising from the Purkinje tissue as ventricular fibrillation triggers have been documented by electrophysiologic studies in MVP patients with aborted sudden death.

The genesis of malignant ventricular arrhythmias in MVP probably recognizes the combination of the substrate (regional myocardial hypertrophy and fibrosis, Purkinje fibers) and the trigger (mechanical stretch) eliciting premature ventricular beats because of a primary morphofunctional abnormality of the mitral valve annulus.

The main clinical challenge is how to identify patients with arrhythmic MVP (which imaging technique and in which patient) and how to treat them to prevent sudden death. Thus, there is a necessity for prospective multicenter studies focusing on the prognostic role of cardiac magnetic resonance and electrophysiologic studies and on the therapeutic efficacy of targeted catheter ablation and mitral valve surgery in reducing the risk of life-threatening arrhythmias, as well as the role of implantable cardioverter defibrillators for primary prevention.

Duration of ischemia is a major determinant of transmurality and severe microvascular obstruction after primary angioplasty: a study performed with contrast-enhanced magnetic resonance

OBJECTIVES

This study sought to assess the relationship between duration of ischemia and both myocardial transmural necrosis (TN) and severe microvascular obstruction (SMO), by contrast-enhanced magnetic resonance (CE-MR), in patients with acute myocardial infarction (AMI) treated with angioplasty (PCI), and to estimate the risk of TN and SMO with the duration of ischemia.

BACKGROUND

The impact of ischemic time on myocardial and microvascular injury is not well characterized in people.

METHODS

We performed CE-MR in 77 patients with first AMI, 5 +/- 3 days after successful PCI. The AMI was labeled as transmural if hyperenhancement at CE-MR was extended to > or =75% of the thickness in two or more ventricular segments. The SMO was identified as areas of late hypoenhancement surrounded by hyperenhanced tissue. The relationship between ischemic time and CE-MR evidence of SMO or TN was evaluated by logistic regression.

RESULTS

Thirteen patients were excluded because of preprocedural Thrombolysis In Myocardial Infarction (TIMI) flow grade 3 of the infarct-related artery. For the remaining 64 patients, the mean time to treatment was 190 +/- 110 min, 45 (65%) patients had TN and 23 (39%) had SMO. Mean pain to balloon time was 90 +/- 40 min, 110 +/- 107 min, and 137 +/- 97 min in patients without TN and SMO, with TN but without SMO, or with both TN and SMO, respectively (p = 0.001). Multivariate analysis showed that time delay was significantly associated both with TN (odds ratio per 30 min, 1.37, p = 0.032), and SMO (odds ratio per 30 min, 1.21; p = 0.021).

CONCLUSIONS

In AMI patients with impaired coronary perfusion undergoing PCI, the risk of TN and SMO increases with the duration of the ischemic time.

Gene discovery by EST sequencing in Toxoplasma gondii reveals sequences restricted to the Apicomplexa

To accelerate gene discovery and facilitate genetic mapping in the protozoan parasite Toxoplasma gondii, we have generated >7000 new ESTs from the 5' ends of randomly selected tachyzoite cDNAs. Comparison of the ESTs with the existing gene databases identified possible functions for more than 500 new T. gondii genes by virtue of sequence motifs shared with conserved protein families, including factors involved in transcription, translation, protein secretion, signal transduction, cytoskeleton organization, and metabolism. Despite this success in identifying new genes, more than 50% of the ESTs correspond to genes of unknown function, reflecting the divergent evolutionary status of this parasite. A newly recognized class of genes was identified based on its similarity to sequences known only from other members of the same phylum, therefore identifying sequences that are apparently restricted to the Apicomplexa. Such genes may underlie pathways common to this group of medically important parasites, therefore identifying potential targets for intervention.

Apicobasal gradient of left ventricular myocardial edema underlies transient T-wave inversion and QT interval prolongation (Wellens' ECG pattern) in Tako-Tsubo cardiomyopathy

BACKGROUND

Tako-Tsubo cardiomyopathy (TTC) presents with chest pain, ST-segment elevation followed by T-wave inversion and QT interval prolongation (Wellens' electrocardiographic [ECG] pattern), and left ventricular dysfunction, which may mimic an acute coronary syndrome.

OBJECTIVE

To assess the pathophysiologic basis of the Wellens' ECG pattern in TTC by characterization of underlying myocardial changes by using cardiac magnetic resonance (CMR).

METHODS

The study population included 20 consecutive patients with TTC (95% women; mean age 65.3 ± 10.4 years) who underwent CMR studies both in the initial phase and after 3-month follow-up by using a protocol that included cine images, T2-weighted sequences for myocardial edema, and post-contrast sequences for late gadolinium enhancement. Quantitative ECG indices of repolarization, such as maximal amplitude of negative T waves, sum of the amplitudes of negative T waves, and maximum corrected QT interval (QTc max), were correlated to CMR findings.

RESULTS

At the time of initial CMR study, there was a significant linear correlation between the apicobasal ratio of T2-weighted signal intensity for myocardial edema and the maximal amplitude of negative T waves (ρ = 0.498; P = .02), sum of the amplitudes of negative T waves (ρ = 0.483; P = .03), and maximum corrected QT interval (ρ = 0.520; P = .02). Repolarization indices were unrelated to either late gadolinium enhancement or quantitative cine parameters. Wellens' ECG abnormalities and myocardial edema showed a parallel time course of development and resolution on initial and follow-up CMR studies.

CONCLUSIONS

Our study results show that the ischemic-like Wellens' ECG pattern in TTC coincides and quantitatively correlates with the apicobasal gradient of myocardial edema as evidenced by using CMR. Dynamic negative T waves and QTc prolongation are likely to reflect the edema-induced transient inhomogeneity and dispersion of repolarization between apical and basal left ventricular regions.

Impact of the presence and amount of myocardial fibrosis by cardiac magnetic resonance on arrhythmic outcome and sudden cardiac death in nonischemic dilated cardiomyopathy

BACKGROUND

Current risk stratification for sudden cardiac death (SCD) in nonischemic dilated cardiomyopathy (NIDC) relies on left ventricular (LV) dysfunction, a poor marker of ventricular electrical instability. Contrast-enhanced cardiac magnetic resonance has the ability to accurately identify and quantify ventricular myocardial fibrosis (late gadolinium enhancement [LGE]).

OBJECTIVE

To evaluate the impact of the presence and amount of myocardial fibrosis on arrhythmogenic risk prediction in NIDC.

METHODS

One hundred thirty-seven consecutive patients with angiographically proven NIDC were enrolled for this study. All patients were followed up for a combined arrhythmic end point including sustained ventricular tachycardia (VT), appropriate implantable cardioverter-defibrillator (ICD) intervention, ventricular fibrillation (VF), and SCD.

RESULTS

LV-LGE was identified in 76 (55.5%) patients. During a median follow-up of 3 years, the combined arrhythmic end point occurred in 22 (16.1%) patients: 8 (5.8%) sustained VT, 9 (6.6%) appropriate ICD intervention, either against VF (n = 5; 3.6%) or VT (n = 4; 2.9%), 3 (2.2%) aborted SCD, and 2 (1.5%) died suddenly. Kaplan-Meier analysis revealed a significant correlation between the LV-LGE presence (not the amount and distribution) and malignant arrhythmic events (P < .001). In univariate Cox regression analysis, LV-LGE (hazard ratio [HR] 4.17; 95% confidence interval [CI] 1.56-11.2; P = .005) and left bundle branch block (HR 2.43; 95% CI 1.01-5.41; P = .048) were found to be associated with arrhythmias. In multivariable analysis, the presence of LGE was the only independent predictor of arrhythmias (HR 3.8; 95% CI 1.3-10.4; P = .01).

CONCLUSIONS

LV-LGE is a powerful and independent predictor of malignant arrhythmic prognosis, while its amount and distribution do not provide additional prognostic value. Contrast-enhanced cardiac magnetic resonance may contribute to identify candidates for ICD therapy not fulfilling the current criteria based on left ventricular ejection fraction.

Imaging study of ventricular scar in arrhythmogenic right ventricular cardiomyopathy: comparison of 3D standard electroanatomical voltage mapping and contrast-enhanced cardiac magnetic resonance

BACKGROUND

The hallmark lesion of arrhythmogenic right ventricular cardiomyopathy (ARVC) is fibrofatty scar replacement. We compared endocardial voltage mapping (EVM) and contrast-enhanced cardiac magnetic resonance (CE-CMR) for imaging scar lesions in ARVC patients.

METHODS AND RESULTS

We studied 23 consecutive ARVC patients (16 males; mean age, 38±12 years) who underwent RV EVM and CE-CMR and 37 control subjects. In 21 (91%) of 23 ARVC patients, RV EVM was abnormal, with a total of 45 electroanatomical scars (EAS): 17 (38%) in the inferobasal region, 12 (26.6%) in the anterolateral region, 8 (17.7%) in the RV outflow tract (RVOT), and 8 (17.7%) in the apex. RV delayed contrast enhancement (DCE) was found in 9 (39%) of 23 patients, with a total of 23 RV DCE scars: 4 (17.4%) in the inferobasal region, 9 (39.1%) in the anterolateral region, 4 (17.4%) in the RVOT, and 6 (26.1%) in the apex. There was a mismatch in 24 RV scars, with 22 EAS not confirmed by DCE and 2 DCE scars (both in the RVOT) undetected by EVM. In 9 (75%) of 12 patients with abnormal RV EVM/normal RV DCE, ≥1 DCEs were identified in the left ventricle (LV). Overall, ventricular DCE was detected in 78% of patients. No control subjects showed either EAS or DCE.

CONCLUSIONS

EVM and CE-CMR allow identification of RV scar lesions in most ARVC patients. CE-CMR is less sensitive than EVM in identifying RV scar lesions. The high prevalence of LV DCE confirms the frequent biventricular involvement and indicates the diagnostic relevance of LV scar detection by CE-CMR.

Meal-induced oxidative stress and low-density lipoprotein oxidation in diabetes: the possible role of hyperglycemia

Oxidative stress and its contribution to low-density lipoprotein (LDL) oxidation have been implicated in the pathogenesis of vascular diabetic complications. However, the relationship between hyperglycemia, hyperinsulinemia, hyperlipidemia, and oxidative stress is still debated. If plasma glucose and/or insulin and/or lipid are some of the most important determinants of oxidative stress in diabetes, then their typical postprandial elevations in diabetes would be expected to favor oxidative stress and LDL oxidation. To test this hypothesis, in type 2 diabetic patients, we evaluated the effects of two different standard meals designed to produce different levels of postprandial hyperglycemia on the plasma oxidative status and LDL oxidation. The meals were administered in randomized order to each of 10 type 2 diabetic patients. Blood samples were collected at baseline and 60 and 120 minutes after the meals. In every sample, plasma levels of glucose, insulin, cholesterol, triglycerides, nonesterified fatty acids (NEFAs), malondialdehyde (MDA), and the total radical-trapping antioxidant parameter (TRAP) were measured. LDL susceptibility to oxidation was evaluated at baseline and after 120 minutes. Plasma glucose, insulin, triglycerides, and MDA increased and NEFAs and TRAP significantly decreased after either meal. The variations in plasma glucose, MDA, and TRAP were significantly greater and LDL was more susceptible to oxidation after the meal that produced a significantly higher degree of hyperglycemia. These results suggest that postprandial hyperglycemia may contribute to oxidative stress in diabetic patients, providing a mechanistic link between hyperglycemia and diabetic vascular disease.

Short-term effects of PM2.5, PM10 and PM2.5-10 on daily mortality in The Netherlands

INTRODUCTION

Information on the relationship between levels of particulate matter (PM) smaller than 2.5 μm and mortality rates in Europe is relatively sparse because of limited availability of PM2.5 measurement data. Even less information is available on the health effects attributable to PM2.5-10, especially for North-West Europe.

OBJECTIVES

To investigate the relationship between various PM size fractions and daily mortality rates.

METHODS

Daily concentrations of PM from the Dutch National Ambient Air Quality Monitoring Network as well as all cause and cause-specific mortality rates in The Netherlands were obtained for the period 2008-2009. Poisson regression analysis using generalized additive models was used, with adjustment for potential confounding including long-term and seasonal trends, influenza incidence, meteorological variables, day of the week, and holidays. Different measures of PM (PM2.5, PM10 and PM2.5-10) were analysed.

RESULTS

PM10 and PM2.5 levels were statistically significantly (p<0.05) associated with all cause and cause-specific deaths. For example, a 10 μg/m(3) increase in previous day PM was associated with 0.8% (95% CI 0.3-1.2) excess risk in all cause mortality for PM2.5 and a 0.6% (CI 0.2-1.0) excess risk for PM10. No appreciable associations were observed for PM2.5-10. Effects of PM10, and PM2.5 were insensitive to adjustment for PM2.5-10, and vice-versa. PM10 and PM2.5 were too highly correlated to disentangle their independent effects.

CONCLUSIONS

PM10 and PM2.5 both were significantly associated with all cause and cause-specific mortality. We were unable to demonstrate significant effects for PM2.5-10, possibly due to the lower temporal variability and the higher exposure misclassification in PM2.5-10 compared to PM10 or PM2.5. The lack of effects of PM2.5-10 in our study should therefore not be interpreted as an indication that PM2.5-10 can be considered harmless.

The translation elongation factor 1A in tumorigenesis, signal transduction and apoptosis: review article

An increasing number of evidences suggest the involvement of the eukaryotic elongation factor 1A, a core component of the protein synthesis machinery, at the onset of cell transformation. In fact, eEF1A is shown to be up-regulated in cell death; moreover, it seems to be involved in the regulation of ubiquitin-mediated protein degradation. In addition, eEF1A undergoes several post-translational modifications, mainly phosphorylation and methylation, that generally influence the activity of the protein. This article summarizes the present knowledges on the several extra-translational roles of eEF1A also in order to understand as the protein synthesis regulatory mechanisms could offer tools for cancer intervention.