Electromechanical mapping versus positron emission tomography and single photon emission computed tomography for the detection of myocardial viability in patients with ischemic cardiomyopathy

OBJECTIVES: We compared catheter-based electromechanical mapping (NOGA system, Biosense-Webster, Haifa, Israel) with positron emission tomography (PET) and single photon emission computed tomography (SPECT) for prediction of reversibly dysfunctional myocardium (RDM) and irreversibly dysfunctional myocardium (IDM) in patients with severe left ventricular dysfunction. Furthermore, we established the optimal discriminatory value of NOGA measurements for distinction between RDM and IDM. BACKGROUND: The NOGA system can detect viable myocardium but has not been used for prediction of post-revascularization contractile function in patients with ischemic cardiomyopathy. METHODS: Twenty patients (19 males, age [mean +/- SD] 60 +/- 16 years, ejection fraction [EF] 29 +/- 6%) underwent viability testing with NOGA and PET or SPECT before revascularization. Left ventricular function was studied at baseline and six months after revascularization. RESULTS: The EF increased to 34 +/- 13% at six months (p < 0.05 vs. baseline). The 58 RDM and 57 IDM regions differed with regard to unipolar voltage amplitude (UVA) (9.2 +/- 3.9 mV vs. 7.6 +/- 4.0 mV, p < 0.05), normalized UVA (106 +/- 54% vs. 75 +/- 39%, p < 0.05), and tracer uptake (76 +/- 17% vs. 60 +/- 20%, p < 0.05). The NOGA local shortening did not distinguish between RDM and IDM (6.4 +/- 5.8% vs. 5.4 +/- 6.6%). By receiver operating characteristic curve analysis, myocardial tracer uptake had better diagnostic performance than UVA (area under curve [AUC] +/- SE: 0.82 +/- 0.04 vs. 0.63 +/- 0.05, p < 0.05) and normalized UVA (AUC +/- SE: 0.70 +/- 0.05, p < 0.05). Optimal threshold was defined as the value yielding sensitivity = specificity for prediction of RDM. Sensitivity and specificity were 59% at a UVA of 8.4 mV, 65% at a normalized UVA of 83%, and 78% at a tracer uptake of 69%. CONCLUSIONS: The NOGA system may discriminate RDM from IDM with optimal discriminatory values for UVA and normalized UVA of 8.4 mV and 83%, respectively. However, the diagnostic performance does not reach the level obtained by PET and SPECT in patients with severe heart failure.     

Response of human alveolar macrophages to ultrafine,fine, and coarse urban air pollution particles

In the lower airways, macrophages are important regulators of inflammation and indispensable in their antimicrobial activities. Thus, air pollution particles, which modulate airway macrophage host defenses may, in susceptible individuals, increase severity of inflammatory and infectious disease. In the present study, size fractionated, ultrafine (UF), fine (PM0.1-2.5), and coarse (PM2.5-10) particulate matter (PM) were collected from 2 urban sites in the Netherlands, and were compared for effects on human alveolar macrophages (AM). Inflammatory cytokine production, phagocytosis, and expression of phagocyte receptor CD11b were assessed in particle-exposed AM. Interleukin (IL)-6 levels induced by PM2.5-10 (20411 pg/mL) were > 10-fold higher than induced by PM0.1-2.5 (1781 pg/mL). Levels induced by PM0.1-2.5 were 2- to 3-fold higher than induced by UF (770 pg/mL) when cells were exposed to the same particle mass. Cytokine induction by the PM was inhibited by antibody to CD14 and required the presence of serum for optimal stimulation, implying that bacterial products or endotoxin were stimulatory moieties in both coarse and fine particulate matter. Phagocytosis of opsonized yeast was inhibited by coarse more than by fine PM, as was yeast-induced oxidative burst. Coarse particles decreased CD11b expression more than fine PM. The UF did not affect these functions. Taken together, these results suggest that PM recognition by human AM involves receptors evolved to recognize microbial cell structures, and that microbial products preferentially found in the coarse particle fraction of PM may be involved in inflammatory events and decreased pulmonary defenses associated with exposure to pollution particles.     

Pharmacokinetics of metformin in patients with gastrointestinal intolerance

Aims

To assess potential causes of metformin intolerance, including altered metformin uptake from the intestine, increased anaerobic glucose utilization and subsequent lactate production, altered serotonin uptake, and altered bile acid pool.

Methods

For this pharmacokinetic study, we recruited 10 severely intolerant and 10 tolerant individuals, matched for age, sex and body mass index. A single 500‐mg dose of metformin was administered, with blood sampling at 12 time points over 24 hours. Blood samples were analysed for metformin, lactate, serotonin and bile acid concentrations, and compared across the phenotypes.

Results

The intolerant individuals were severely intolerant to 500 mg metformin. No significant difference was identified between tolerant and intolerant cohorts in metformin pharmacokinetics: median (interquartile range [IQR]) peak concentration 2.1 (1.7‐2.3) mg/L and 2.0 (1.8‐2.2) mg/L, respectively (P = .76); time to peak concentration 2.5 hours; median (IQR) area under the curve (AUC)_0–24 16.9 (13.9‐18.6) and 13.9 (12.9‐16.8) mg/L*h, respectively (P = .72). Lactate concentration peaked at 3.5 hours, with mean peak concentration of 2.4 mmol/L in both cohorts (95% CI 2.0‐2.8 and 1.8‐3.0 mmol/L, respectively), and similar incremental AUC_0–24 in each cohort: tolerant cohort 6.98 (95% CI 3.03‐10.93) and intolerant cohort 4.47 (95% CI –3.12‐12.06) mmol/L*h (P = .55). Neither serotonin nor bile acid concentrations were significantly different.

Conclusions

Despite evidence of severe intolerance in our cohort, there was no significant difference in metformin pharmacokinetics or systemic measures of lactate, serotonin or bile acids. This suggests that metformin intolerance may be attributable to local factors within the lumen or enterocyte.     

Reduced skeletal muscle mitochondrial respiration and improved glucose metabolism in nondiabetic obese women during a very low calorie dietary intervention leading to rapid weight loss

Reduced oxidative capacity of skeletal muscle has been proposed to lead to accumulation of intramyocellular triglyceride (IMTG) and insulin resistance. We have measured mitochondrial respiration before and after a 10% low-calorie-induced weight loss in young obese women to examine the relationship between mitochondrial function, IMTG, and insulin resistance. Nine obese women (age, 32.3 years [SD, 3.0]; body mass index, 33.4 kg/m² [SD, 2.6]) completed a 53-day (SE, 3.8) very low calorie diet (VLCD) of 500 to 600 kcal/d without altering physical activity. The target of the intervention was a 10% weight loss; and measurements of mitochondrial respiration, IMTG, respiratory exchange ratio, citrate synthase activity, mitochondrial DNA copy number, plasma insulin, 2-hour oral glucose tolerance test, and free fatty acids were performed before and after weight loss. Mitochondrial respiration was measured in permeabilized muscle fibers using high-resolution respirometry. Average weight loss was 11.5% (P < .05), but the levels of IMTG remained unchanged. Fasting plasma glucose, plasma insulin homeostasis model assessment of insulin resistance, and insulin sensitivity index (composite) obtained during 2-hour oral glucose tolerance test improved significantly. Mitochondrial respiration per milligram tissue decreased by approximately 25% (P < .05), but citrate synthase activity and mitochondrial DNA copy number remained unchanged. Respiratory exchange ratio decreased from 0.87 (SE, 0.01) to 0.79 (SE, 0.02) (P < .05) as a sign of increased whole-body fat oxidation. Markers of insulin sensitivity improved after the very low calorie diet; but mitochondrial function decreased, and IMTG remained unchanged. Our results do not support a direct relationship between mitochondrial function and insulin resistance in young obese women and do not support a direct relationship between IMTG and insulin sensitivity in young obese women during weight loss.     

Self-harm and self-poisoning in southern India: choice of poisoning agents and treatment

Objective  To record cases of suicide and attempted suicide among a population of 108 000 people living in a primarily rural area of southern India, with the aim of guiding policies and strategies to restrict access to poisonous compounds at community level.
Method  Community-based surveillance over a period of 2 years.
Results and conclusion  The overall suicide rate was 71.4 per 100 000 population; the highest burden was among men. Most people died through hanging (81, 54%) and self-poisoning (46, 31%). Of the 46 who died from self-poisoning, 78.3% had taken pesticides and 19.7% had eaten poisonous plants. Eighty per cent of the self-poisoning cases obtained the poisonous substance in or in close proximity to the home, highlighting the importance of safe storage in the domestic environment. Of the 110 fatal and non-fatal self-poisoning cases, 87 (57.5%) were taken for treatment; 50 (57.4%) went to government hospitals and 37 (42.5%) to private facilities. This indicates the importance of including the private sector in the efforts to improve case management. Furthermore, the fact that 31 (67%) of the self-poisoning patients, who eventually died, were alive after 4 h provides an incentive to focus on improved case management and access to health services.     

Axial force measurement for esophageal function testing

The esophagus serves to transport food and fluid from the pharynx to the stomach. Manometry has been the ＂golden standard＂ for the diagnosis of esophageal motility diseases for many decades. Hence, esophageal function is normally evaluated by means of manometry even though it reflects the squeeze force （force in radial direction） whereas the bolus moves along the length of esophagus in a distal direction. Force measurements in the longitudinal （axial） direction provide a more direct measure of esophageal transport function. The technique used to record axial force has developed from external force transducers over in-vivo strain gauges of various sizes to electrical impedance based measurements. The amplitude and duration of the axial force has been shown to be as reliable as manometry. Normal, as well as abnormal, manometric recordings occur with normal bolus transit, which have been documented using imaging modalities such as radiography and scintigraphy. This inconsistency using manometry has also been documented by axial force recordings. This underlines the lack of information when diagnostics are based on manometry alone. Increasing the volume of a bag mounted on a probe with combined axial force and manometry recordings showed that axial force amplitude increased by 130% in contrast to an increase of 30% using manometry. Using axial force in combination with manometry provides a more complete picture of esophageal motility, and the current paper outlines the advantages of using this method.     

Microsatellite instability and alternative genetic pathway in intrahepatic cholangiocarcinoma

BACKGROUND/AIMS: Intrahepatic cholangiocarcinoma (ICC) arises from intrahepatic bile duct epithelium and is the second most prevalent among primary liver cancers. The aim of this study was to clarify the mechanism of cholangiocarcinogenesis. METHODS: We studied the incidence of microsatellite instability (MSI) involving eight highly polymorphic microsatellite markers and alternations of the K-ras, p53 and mdm-2 genes in human ICC tissues. Overexpression of mdm-2 oncoprotein was also immunohistochemically studied. RESULTS: Of all 65 cases examined, K-ras gene mutation was found in three cases (4.6%) at codon 12. Analysis of p53 alterations was performed in 28 cases including 22 frozen samples and mutations were found in three cases (10.7%). Overexpression of mdm-2 protein was observed in 25 (41.7%) out of 60 cases analyzed. In 22 frozen samples, seven (31.8%) cases showed mdm-2 amplification and four (18.2%) cases revealed MSI-positive phenotype. Among the cases analyzed, all the tumors with mdm-2 amplification/overexpression harbored the wild-type p53 gene and all the microsatellite instability-positive cases were from mass-forming (MF) + periductal-infiltrating (PI) subtype. CONCLUSIONS: These results suggest that mdm-2 plays a role, which might be partially through inhibiting p53 activity, in cholangiocarcinogenesis and that M     

Rivaroxaban Versus Warfarin and Risk of Post-Thrombotic Syndrome Among Patients with Venous Thromboembolism

Background

The effectiveness of rivaroxaban to reduce post-thrombotic syndrome in patients with venous thromboembolism is largely unknown. We compared rates of post-thrombotic syndrome in patients given rivaroxaban versus warfarin in a cohort of patients with incident venous thromboembolism receiving routine clinical care.