Diastolic dysfunction of the cardiac allograft and maximal exercise capacity

BACKGROUND: Peak oxygen uptake (peak Vo(2)) is an established integrative measurement of maximal exercise capacity in cardiovascular disease. After heart transplantation (HTx) peak Vo(2) remains reduced despite normal systolic left ventricular function, which highlights the relevance of diastolic function. In this study we aim to characterize the predictive significance of cardiac allograft diastolic function for peak Vo(2). METHODS: Peak Vo(2) was measured using a ramp protocol on a bicycle ergometer. Left ventricular (LV) diastolic function was assessed with tissue Doppler imaging sizing the velocity of the early (Ea) and late (Aa) apical movement of the mitral annulus, and conventional Doppler measuring early (E) and late (A) diastolic transmitral flow propagation. Correlation coefficients were calculated and linear regression models fitted. RESULTS: The post-transplant time interval of the 39 HTxs ranged from 0.4 to 20.1 years. The mean age of the recipients was 55 +/- 14 years and body mass index (BMI) was 25.4 +/- 3.9 kg/m(2). Mean LV ejection fraction was 62 +/- 4%, mean LV mass index 108 +/- 22 g/m(2) and mean peak Vo(2) 20.1 +/- 6.3 ml/kg/min. Peak Vo(2) was reduced in patients with more severe diastolic dysfunction (pseudonormal or restrictive transmitral inflow pattern), or when E/Ea was > or =10. Peak Vo(2) correlated with recipient age (r = -0.643, p < 0.001), peak heart rate (r = 0.616, p < 0.001) and BMI (r = -0.417, p = 0.008). Of all echocardiographic measurements, Ea (r = 0.561, p < 0.001) and Ea/Aa (r = 0.495, p = 0.002) correlated best. Multivariate analysis identified age, heart rate, BMI and Ea/Aa as independent predictors of peak Vo(2). CONCLUSIONS: Diastolic dysfunction is relevant for the limitation of maximal exercise capacity after HTx.

Impact of B-type natriuretic peptide on short-term clinical outcomes following transcatheter aortic valve implantation

Aims: We aimed to assess the impact of B-type natriuretic peptide (BNP) on short-term outcomes in patients undergoing transcatheter aortic valve implantation (TAVI). Methods and results: Of 500 consecutive patients with severe aortic stenosis undergoing TAVI at our institution, we studied 340 patients who had a BNP assessment prior to TAVI. Patients were divided into tertiles - low: BNP ≤201 pg/mL (n=114), mid: BNP 202-595 pg/mL (n=113) and high: BNP ≥596 pg/mL (n=113). The primary endpoint was all-cause mortality, cardiac death and major adverse cardiac and cerebrovascular events (MACCE; death, major stroke and myocardial infarction) at 30 days. Compared with low tertile, high tertile patients were at higher baseline surgical risk (STS score 5.5±3.0 vs. 7.4±4.1, p=0.002). On echocardiography, high tertile patients had smaller valve areas (0.74±0.21 vs. 0.66±0.23 cm2, p=0.008), higher left ventricular (LV) mass indices (123.40±33.66 vs. 168.22±47.96 g/m2, p<0.001) and lower LV ejection fractions (61.59±7.18 vs. 42.65±15.41%, p<0.001) as compared with low tertile patients. At 30 days, a significantly higher incidence of death (hazard ratio [HR] 7.41, p=0.001) cardiac death (HR 5.82, p=0.006) and MACCE (HR 9.04, p<0.001) was observed among high as compared to low tertile patients. Conclusions: In TAVI patients, higher BNP values at baseline are associated with an increased risk for an adverse event periprocedurally and after 30 days, respectively.

An Sp1/Sp3 binding polymorphism confers methylation protection.

Hundreds of genes show aberrant DNA hypermethylation in cancer, yet little is known about the causes of this hypermethylation. We identified RIL as a frequent methylation target in cancer. In search for factors that influence RIL hypermethylation, we found a 12-bp polymorphic sequence around its transcription start site that creates a long allele. Pyrosequencing of homozygous tumors revealed a 2.1-fold higher methylation for the short alleles (P<0.001). Bisulfite sequencing of cancers heterozygous for RIL showed that the short alleles are 3.1-fold more methylated than the long (P<0.001). The comparison of expression levels between unmethylated long and short EBV-transformed cell lines showed no difference in expression in vivo. Electrophorectic mobility shift assay showed that the inserted region of the long allele binds Sp1 and Sp3 transcription factors, a binding that is absent in the short allele. Transient transfection of RIL allele-specific transgenes showed no effects of the additional Sp1 site on transcription early on. However, stable transfection of methylation-seeded constructs showed gradually decreasing transcription levels from the short allele with eventual spreading of de novo methylation. In contrast, the long allele showed stable levels of expression over time as measured by luciferase and approximately 2-3-fold lower levels of methylation by bisulfite sequencing (P<0.001), suggesting that the polymorphic Sp1 site protects against time-dependent silencing. Our finding demonstrates that, in some genes, hypermethylation in cancer is dictated by protein-DNA interactions at the promoters and provides a novel mechanism by which genetic polymorphisms can influence an epigenetic state.

Association of putative enteroaggregative Escherichia coli virulence genes and biofilm production in isolates from travelers to developing countries.

Enteroaggregative Escherichia coli (EAEC) is an emerging enteric pathogen that causes acute and chronic diarrhea among children, human immunodeficiency virus-infected patients, and travelers to developing regions of the world. The pathogenesis of EAEC strains involves the production of biofilm. In this study, we determined the association between presence of putative EAEC virulence genes and biofilm formation in 57 EAEC isolates (as defined by HEp-2 adherence) from travelers with diarrhea and in 18 EAEC isolates from travelers without diarrhea. Twelve nondiarrheagenic E. coli isolates from healthy travelers were used as controls. Biofilm formation was measured by using a microtiter plate assay with the crystal violet staining method, and the presence of the putative EAEC virulence genes aap, aatA, aggR, astA, irp2, pet, set1A, and shf was determined by PCR. EAEC isolates were more likely to produce biofilm than nondiarrheagenic E. coli isolates (P = 0.027), and the production of biofilm was associated with the virulence genes aggR, set1A, aatA, and irp2, which were found in 16 (40%), 17 (43%), 10 (25%), and 27 (68%) of the biofilm producers versus only 4 (11%), 6 (6%), 2 (6%), and 15 (43%) in non-biofilm producers (P = 0.008 for aggR, P = 0.0004 for set1A, P = 0.029 for aatA, and P = 0.04 for irp2). Although the proportion of EAEC isolates producing biofilm in patients with diarrhea (51%) was similar to that in patients without diarrhea (61%), biofilm production was related to the carriage of aggR (P = 0.015), set1A (P = 0.001), and aatA (P = 0.025). Since aggR is a master regulator of EAEC, the presence of aap (P = 0.004), astA (P = 0.001), irp2 (P = 0.0006), pet (P = 0.002), and set1A (P = 0.014) in an aggR versus an aggR-lacking background was investigated and was also found to be associated with biofilm production. This study suggests that biofilm formation is a common phenomenon among EAEC isolates derived from travelers with or without diarrhea and that multiple genes associated with biofilm formation are regulated by aggR.

Combined aerobic/inspiratory muscle training vs. aerobic training in patients with chronic heart failure: The Vent-HeFT trial: a European prospective multicentre randomized trial

AIMS Vent-HeFT is a multicentre randomized trial designed to investigate the potential additive benefits of inspiratory muscle training (IMT) on aerobic training (AT) in patients with chronic heart failure (CHF). METHODS AND RESULTS Forty-three CHF patients with a mean age of 58 ± 12 years, peak oxygen consumption (peak VO2 ) 17.9 ± 5 mL/kg/min, and LVEF 29.5 ± 5% were randomized to an AT/IMT group (n = 21) or to an AT/SHAM group (n = 22) in a 12-week exercise programme. AT involved 45 min of ergometer training at 70-80% of maximum heart rate, three times a week for both groups. In the AT/IMT group, IMT was performed at 60% of sustained maximal inspiratory pressure (SPImax ) while in the AT/SHAM group it was performed at 10% of SPImax , using a computer biofeedback trainer for 30 min, three times a week. At baseline and at 3 months, patients were evaluated for exercise capacity, lung function, inspiratory muscle strength (PImax ) and work capacity (SPImax ), quality of life (QoL), LVEF and LV diameter, dyspnoea, C-reactive protein (CRP), and NT-proBNP. IMT resulted in a significantly higher benefit in SPImax (P = 0.02), QoL (P = 0.002), dyspnoea (P = 0.004), CRP (P = 0.03), and NT-proBNP (P = 0.004). In both AT/IMT and AT/SHAM groups PImax (P < 0.001, P = 0.02), peak VO2 (P = 0.008, P = 0.04), and LVEF (P = 0.005, P = 0.002) improved significantly; however, without an additional benefit for either of the groups. CONCLUSION This randomized multicentre study demonstrates that IMT combined with aerobic training provides additional benefits in functional and serum biomarkers in patients with moderate CHF. These findings advocate for application of IMT in cardiac rehabilitation programmes.

Plasma T-cadherin negatively associates with coronary lesion severity and acute coronary syndrome.

AIMS This study evaluated associations between plasma T-cadherin levels and severity of atherosclerotic disease. METHODS AND RESULTS Three hundred and ninety patients undergoing coronary angiography were divided into three groups based on clinical and angiographic presentation: a group (n=40) with normal coronary arteries, a group (n=250) with chronic coronary artery disease and a group (n=100) with acute coronary syndrome. Plasma T-cadherin levels were measured by double sandwich ELISA. Intravascular ultrasound data of the left-anterior descending artery were acquired in a subgroup of 284 patients. T-cadherin levels were lower in patients with acute coronary syndrome than in normal patients (p=0.007) and patients with chronic coronary artery disease (p=0.002). Levels were lower in males (p=0.002), in patients with hypertension (p=0.002) and inpatients with diabetes (p=0.008), and negatively correlated with systolic blood pressure (p=0.014), body mass index (p=0.001) and total number of risk factors (p=0.001). T-cadherin negatively associated with angiographic severity of disease (p=0.001) and with quantitative intravascular ultrasound measures of lesion severity (p<0.001 for plaque, necrotic core and dense calcium volumes). Significant associations between T-cadherin and intravascular ultrasound measurements persisted even if the regression model was adjusted for the presence of acute coronary syndrome. Multivariate analysis identified a strong (p=0.002) negative association of T-cadherin with acute coronary syndrome, and lower T-cadherin levels significantly (p=0.002) associated with a higher risk of acute coronary syndrome independently of age, gender and cardiovascular risk factors. CONCLUSIONS A reduction in plasma T-cadherin levels is associated with increasing severity of coronary artery disease and a higher risk for acute coronary syndrome.

Prevention of vascular dysfunction and arterial hypertension in mice generated by assisted reproductive technologies by addition of melatonin to culture media.

Assisted reproductive technologies (ART) induce vascular dysfunction in humans and mice. In mice, ART-induced vascular dysfunction is related to epigenetic alteration of the endothelial nitric oxide synthase (eNOS) gene, resulting in decreased vascular eNOS expression and nitrite/nitrate synthesis. Melatonin is involved in epigenetic regulation, and its administration to sterile women improves the success rate of ART. We hypothesized that addition of melatonin to culture media may prevent ART-induced epigenetic and cardiovascular alterations in mice. We, therefore, assessed mesenteric-artery responses to acetylcholine and arterial blood pressure, together with DNA methylation of the eNOS gene promoter in vascular tissue and nitric oxide plasma concentration in 12-wk-old ART mice generated with and without addition of melatonin to culture media and in control mice. As expected, acetylcholine-induced mesenteric-artery dilation was impaired (P = 0.008 vs. control) and mean arterial blood pressure increased (109.5 ± 3.8 vs. 104.0 ± 4.7 mmHg, P = 0.002, ART vs. control) in ART compared with control mice. These alterations were associated with altered DNA methylation of the eNOS gene promoter (P < 0.001 vs. control) and decreased plasma nitric oxide concentration (10.1 ± 11.1 vs. 29.5 ± 8.0 μM) (P < 0.001 ART vs. control). Addition of melatonin (10(-6) M) to culture media prevented eNOS dysmethylation (P = 0.005, vs. ART + vehicle), normalized nitric oxide plasma concentration (23.1 ± 14.6 μM, P = 0.002 vs. ART + vehicle) and mesentery-artery responsiveness to acetylcholine (P < 0.008 vs. ART + vehicle), and prevented arterial hypertension (104.6 ± 3.4 mmHg, P < 0.003 vs. ART + vehicle). These findings provide proof of principle that modification of culture media prevents ART-induced vascular dysfunction. We speculate that this approach will also allow preventing ART-induced premature atherosclerosis in humans.

CT-guided infiltration saves surgical intervention and fastens return to work compared to anatomical landmark-guided infiltration in patients with lumbosciatica

BACKGROUND Infiltration procedures are a common treatment of lumbar radiculopathy. There is a wide variety of infiltration techniques without an established gold standard. Therefore, we compared the effectiveness of CT-guided transforaminal infiltrations versus anatomical landmark-guided transforaminal infiltrations at the lower lumbar spine in case of acute sciatica at L3-L5. METHODS A retrospective chart review was conducted of 107 outpatients treated between 2009 and 2011. All patients were diagnosed with lumbar radiculopathic pain secondary to disc herniation in L3-L5. A total of 52 patients received CT-guided transforaminal infiltrations; 55 patients received non-imaging-guided nerve root infiltrations. The therapeutic success was evaluated regarding number of physician contacts, duration of treatment, type of analgesics used and loss of work days. Defined endpoint was surgery at the lower lumbar spine. RESULTS In the CT group, patients needed significantly less oral analgesics (p < 0.001). Overall treatment duration and physician contacts were significantly lower in the CT group (p < 0.001 and 0.002) either. In the CT group, patients lost significant fewer work days due to incapacity (p < 0.001). Surgery had to be performed in 18.2 % of the non-imaging group patients (CT group: 1.9 %; p = 0.008). CONCLUSION This study shows that CT-guided periradicular infiltration in lumbosciatica caused by intervertebral disc herniation is significantly superior to non-imaging, anatomical landmark-guided infiltration, regarding the parameters investigated. The high number of treatment failures in the non-imaging group underlines the inferiority of this treatment concept.

Fluorophotometry is a sensitive method/technique to evaluate epithelial permeability in murine experimental dry eye

Purpose. Fluorophotometry is a well validated method for assessing corneal permeability in human subjects. However, with the growing importance of basic science animal research in ophthalmology, fluorophotometry’s use in animals must be further evaluated. The purpose of this study was to evaluate corneal epithelial permeability following desiccating stress using the modified Fluorotron Master™. ^ Methods. Corneal permeability was evaluated prior to and after subjecting 6-8 week old C57BL/6 mice to experimental dry eye (EDE) for 2 and 5 days (n=9/time point). Untreated mice served as controls. Ten microliters of 0.001% sodium fluorescein (NaF) were instilled topically into each mouse’s left eye to create an eye bath, and left to permeate for 3 minutes. The eye bath was followed by a generous wash with Buffered Saline Solution (BSS) and alignment with the Fluorotron Master™. Seven corneal scans using the Fluorotron Master were performed during 15 minutes (1 st post-wash scans), followed by a second wash using BSS and another set of five corneal scans (2nd post-wash scans) during the next 15 minutes. Corneal permeability was calculated using data calculated with the FM™ Mouse software. ^ Results. When comparing the difference between the Post wash #1 scans within the group and the Post wash #2 scans within the group using a repeated measurement design, there was a statistical difference in the corneal fluorescein permeability of the Post-wash #1 scans after 5 days (1160.21±108.26 vs. 1000.47±75.56 ng/mL, P<0.016 for UT-5 day comparison 8 [0.008]), but not after only 2 days of EDE compared to Untreated mice (1115.64±118.94 vs. 1000.47±75.56 ng/mL, P>0.016 for UT-2 day comparison [0.050]). There was no statistical difference between the 2 day and 5 day Post wash #1 scans (P=.299). The Post-wash #2 scans demonstrated that EDE caused a significant NaF retention at both 2 and 5 days of EDE compared to baseline, untreated controls (1017.92±116.25, 1015.40±120.68 vs. 528.22±127.85 ng/mL, P<0.05 [0.0001 for both]). There was no statistical difference between the 2 day and 5 day Post wash #2 scans (P=.503). The comparison between the Untreated post wash #1 with untreated post wash #2 scans using a Paired T-test showed a significant difference between the two sets of scans (P=0.000). There is also a significant difference between the 2 day comparison and the 5 day comparison (P values = 0.010 and 0.002, respectively). ^ Conclusion. Desiccating stress increases permeability of the corneal epithelium to NaF, and increases NaF retention in the corneal stroma. The Fluorotron Master is a useful and sensitive tool to evaluate corneal permeability in murine dry eye, and will be a useful tool to evaluate the effectiveness of dry eye treatments in animal-model drug trials.^

Health significance of chlorination byproducts in drinking water: The Houston experience: A continuation study

Background. Houston, Texas, once obtained all its drinking water from underground sources. However, in 1853, the city began supplementing its water from the surface source Lake Houston. This created differences in the exposure to disinfection byproducts (DBPs) in different parts of Houston. Trihalomethanes (THMs) are the most common DBP and are useful indicators of DBPs in treated drinking water. This study examines the relationship between THMs in chlorinated drinking water and the incidence of bladder cancer in Houston. ^ Methods. Individual bladder cancer deaths, from 1975 to 2004, were assigned to four surface water exposure areas in Houston utilizing census tracts—area A used groundwater the longest, area B used treated lake water the longest, area C used treated lake water the second longest, and area D used a combination of groundwater and treated lake water. Within each surface water exposure area mortality rates were calculated in 5 year intervals by four race-gender categories. Linear regression models were fitted to the bladder cancer mortality rates over the entire period of available data (1990–2004). ^ Results. A decrease in bladder cancer mortality was observed amongst white males in area B (p = 0.030), white females in area A (p = 0.008), non-white males in area D (p = 0.003), and non-white females in areas A and B (p = 0.002 & 0.001). Bladder cancer mortality differed by race-gender and time (p ≤ 0.001 & p ≤ 0.001), but not by surface water exposure area (p = 0.876). ^ Conclusion. The relationship between bladder cancer mortality and the four surface water exposure areas (signifying THM exposure) was insignificant. This result could be attributable to Houston controlling for THMs starting in the early 1980’s by using chloramine as a secondary disinfectant in the drinking water purification process.^

Geochemistry, clay mineralogy and grain size distribution in various sediment cores drilled during ODP Leg 119 on the Antarctic continental shelf off Prydz Bay

Drilling was undertaken at five sites (739-743) on ODP Leg 119 on a transect across the continental shelf of Prydz Bay, East Antarctica, to elucidate the long-term glacial history of the area and to examine the importance of the area with respect to the development of the East Antarctic ice sheet as a whole. In addition to providing a record of glaciation spanning 36 m.y. or more, Leg 119 has provided information concerning the development of a continental margin under the prolonged influence of a major ice sheet. This has allowed the development of a sedimentary model that may be applicable not only to other parts of the Antarctic continental margin, but also to northern high-latitude continental shelves. The cored glacial sedimentary record in Prydz Bay consists of three major sequences, dominated by diamictite: 1. An upper flat-lying sequence that ranges in thickness from a few meters in inner and western Prydz Bay to nearly 250 m in the outer or eastern parts of the bay. The uppermost few meters consist of Holocene diatom ooze and diatomaceous mud with a minor ice-rafted component overlying diamicton and diamictite of late Miocene to Quaternary age. The diamictite is mainly massive, but stratified varieties and minor mudstone and diatomite also occur. 2. An upper prograding sequence cored at Sites 739 and 743, unconformly below the flat-lying sequence. This consists of a relatively steep (4° inclination) prograding wedge with a number of discrete sedimentary packages. At Sites 739 and 743 the sequence is dominated by massive and stratified diamictite, some of which shows evidence of slumping and minor debris flowage. 3. A lower, more gently inclined, prograding sequence lies unconformably below the flat-lying sequence at Site 742 and the upper prograding sequence at Site 739. This extends to the base of both sites, to 316 and 487 mbsf, respectively. It is dominated by massive, relatively clast-poor diamictite which is kaolinite-rich, light in color, and contains sporadic carbonate-cemented layers. The lower part of Site 742 includes well-stratified diamictites and very poorly sorted mudstones. The base of this site has indications of large-scale soft-sediment deformation and probably represents proximity to the base of the glacial sequence. Facies analysis of the Prydz Bay glacial sequence indicates a range of depositional environments. Massive diamictite is interpreted largely as waterlain till, deposited close to the grounding line of a floating glacier margin, although basal till and debris flow facies are also present. Weakly stratified diamictite is interpreted as having formed close to or under the floating ice margin and influenced by the input of marine diatomaceous sediment (proximal glaciomarine setting). Well-stratified diamictite has a stronger marine input, being more diatom-rich, and probably represents a proximal-distal glaciomarine sediment with the glaciogenic component being supplied by icebergs. Other facies include a variety of mudstones and diatom-rich sediments of marine origin, in which an ice-rafted component is still significant. None of the recovered sediments are devoid of a glacial influence. The overall depositional setting of the prograding sequence is one in which the grounded ice margin is situated close to the shelf edge. Progradation was achieved primarily by deposition of waterlain till. The flat-lying sequence illustrates a complex sequence of advances and retreats across the outer part of the shelf, with intermittent phases of ice loading and erosion. The glacial chronology is based largely on diatom stratigraphy, which has limited resolution. It appears that ice reached the paleoshelf break by earliest Oligocene, suggesting full-scale development of the East Antarctic ice sheet by that time. The ice sheet probably dominated the continental margin for much of Oligocene to middle Miocene time. Retreat, but not total withdrawal of the ice sheet, took place in late Miocene to mid-Pliocene time. The late Pliocene to Pleistocene was characterized by further advances across, and progradation of, the continental shelf. Holocene time has been characterized by reduced glacial conditions and a limited influence of glacial processes on sedimentation.