Strain Pattern on Electrocardiogram Is Associated with Increased Carotid Intima-Media Thickness in Patients with Aortic Valve Stenosis.

BACKGROUND: Coronary artery disease is present in at least 30% of patients with degenerative aortic stenosis (AS). Atherosclerosis also performs an important role in the progression of AS, because of the similarities of pathological mechanisms in both conditions. The electrocardiogram (EKG) strain pattern is associated with structural myocardial change and subendocardial ischemia and has been worldwide used as a marker of AS severity. We hypothesized that EKG strain pattern would be a marker of atherosclerosis as well in AS patients. The aim of this study was to associate the presence of EKG strain pattern in AS patients with the carotid intima-media thickness (CIMT). METHODS: Fifty-two consecutive patients referred from the cardiology clinic with moderate or severe AS were included in the study and underwent clinical evaluation, EKG, transthoracic echocardiography, and carotid ultrasonography, following statistical analysis of the results. RESULTS: There was a significant association between left ventricular EKG strain and increased CIMT (P = 0.001). The presence of strain increased the odds of abnormal CIMT (P = 0.004, odds ratio 9.7, 95% confidence interval 2.4-45.0), in a model adjusted for age and clinical diagnosis of systemic arterial hypertension. Additionally, EKG strain was associated with the presence of atherosclerotic plaque in at least one carotid artery (P = 0.011). CONCLUSION: Our results suggest that AS patients with EKG strain pattern should be further investigated for the diagnosis of subclinical atherosclerotic disease.

Microbial production of Propionic and Succinic acid from Sorbitol using Propionibacterium acidipropionici.

Three sequential fermentative batches were carried out with cell recycle in four simultaneously operating bioreactors maintained at pH 6.5, 30°C, and 100 rpm. P. acidipropionici ATCC 4875 was able to produce propionic and succinic acid from sorbitol. The concentration of propionic acid decreased slightly from 39.5 ± 5.2 g L(-1) to 34.4 ± 1.9 g L(-1), and that of succinic acid increased significantly from 6.1 ± 2.1 g L(-1) to 14.8 ± 0.9 g L(-1) through the sequential batches. In addition, a small amount of acetic acid was produced that decreased from 3.3 ± 0.4 g L(-1) to 2.0 ± 0.3 g L(-1) through the batches. The major yield for propionic acid was 0.613 g g(-1) in the first batch and succinic acid it was 0.212 g g(-1) in the third batch. The minor yield of acetic acid was 0.029 g g(-1), in the second and third batches.

Effect of immobilized cells in calcium alginate beads in alcoholic fermentation.

Saccharomyces cerevisiae cells were immobilized in calcium alginate and chitosan-covered calcium alginate beads and studied in the fermentation of glucose and sucrose for ethanol production. The batch fermentations were carried out in an orbital shaker and assessed by monitoring the concentration of substrate and product with HPLC. Cell immobilization in calcium alginate beads and chitosan-covered calcium alginate beads allowed reuse of the beads in eight sequential fermentation cycles of 10 h each. The final concentration of ethanol using free cells was 40 g L-1 and the yields using glucose and sucrose as carbon sources were 78% and 74.3%, respectively. For immobilized cells in calcium alginate beads, the final ethanol concentration from glucose was 32.9 ± 1.7 g L-1 with a 64.5 ± 3.4% yield, while the final ethanol concentration from sucrose was 33.5 ± 4.6 g L-1 with a 64.5 ± 8.6% yield. For immobilized cells in chitosan-covered calcium alginate beads, the ethanol concentration from glucose was 30.7 ± 1.4 g L-1 with a 61.1 ± 2.8% yield, while the final ethanol concentration from sucrose was 31.8 ± 6.9 g L-1 with a 62.1 ± 12.8% yield. The immobilized cells allowed eight 10 h sequential reuse cycles to be carried out with stable final ethanol concentrations. In addition, there was no need to use antibiotics and no contamination was observed. After the eighth cycle, there was a significant rupture of the beads making them inappropriate for reuse.

A highly sensitive amperometric sensor for oxygen based on iron(II) tetrasulfonated phthalocyanine and iron(III) tetra-(N-methyl-pyridyl)-porphyrin multilayers.

The development of a highly sensitive sensor for oxygen is proposed using a glassy carbon (GC) electrode modified with alternated layers of iron(II) tetrasulfonated phthalocyanine (FeTsPc) and iron(III) tetra-(N-methyl-pyridyl)-porphyrin (FeT4MPyP). The modified electrode showed excellent catalytic activity for the oxygen reduction. The reduction potential of the oxygen was shifted about 330 mV toward less negative values with this modified electrode, presenting a peak current much higher than those observed on a bare GC electrode. Cyclic voltammetry and rotating disk electrode (RDE) experiments indicated that the oxygen reduction reaction involves 4 electrons with a heterogenous rate constant (k(obs)) of 3x10(5) mol(-1) L s(-1). A linear response range from 0.2 up to 6.4 mg L(-1), with a sensitivity of 4.12 microA L mg(-1) (or 20.65 microA cm(-2) L mg(-1)) and a detection limit of 0.06 mg L(-1) were obtained with this sensor. The repeatability of the proposed sensor, evaluated in terms of relative standard deviation (R.S.D.) was 2.0% for 10 measurements of a solution of 6.4 mg L(-1) oxygen. The sensor was applied to determine oxygen in pond and tap water samples showing to be a promising tool for this purpose.