Inhibition of human LDL lipid peroxidation by phenol-rich beverages and their impact on plasma total antioxidant capacity in humans

Mounting evidence shows that phenol-rich beverages exert strong antioxidant activity. However, in vivo evidence has produced conflicting results. In the present study, we studied the impact of the ingestion of 300 mL of black and green tea, alcohol-free red wine, alcohol-free white wine, or water on plasma total antioxidant capacity in five healthy volunteers. Red wine has the highest content of phenolics (3.63 +/- 0.48 g QE/L), followed by green tea (2.82 +/- 0.07 g QE/L), black tea (1.37 +/- 0.15 g QE/L), and white wine (0.31 +/- 0.01 g QE/L). Plasma total antioxidant capacity values of subjects who drank green tea rose at 30 min (P < 0.05). After black tea and red wine ingestion, the peaks were at 50 min (P < 0.05 and P < 0.01, respectively). No changes were observed in the control and white wine groups. Red wine and green tea were the most efficient in protecting low density lipoprotein from oxidation driven by peroxyl and ferril radicals, respectively. Phenol-rich beverages are a natural source of antioxidants; however, the phenolic content alone cannot be considered an index of their in vivo antioxidant activity.     

Loop Dynamics of the Extracellular Domain of Human Tissue Factor and Activation of Factor VIIa

In the crystal structure of the complex between the soluble extracellular domain of tissue factor (sTF) and active-site-inhibited VIIa, residues 91 and 92 in the Pro⁷⁹-Pro⁹² loop of sTF interact with the catalytic domain of VIIa. It is not known, however, whether this loop has a role in allosteric activation of VIIa. Time-resolved fluorescence anisotropy measurements of probes covalently bound to sTF mutants E84C and T121C show that binding uninhibited Factor VIIa affects segmental motions in sTF. Glu⁸⁴ resides in the Pro⁷⁹-Pro⁹² loop, and Thr¹²¹ resides in the turn between the first and second antiparallel β-strands of the sTF subdomain that interacts with the Gla and EGF1 domains of VIIa; neither Glu⁸⁴ nor Thr¹²¹ makes direct contact with VIIa. Probes bound to T121C report limited segmental flexibility in free sTF, which is lost after VIIa binding. Probes bound to E84C report substantial segmental flexibility in the Pro⁷⁹-Pro⁹² loop in free sTF, which is greatly reduced after VIIa binding. Thus, VIIa binding reduces dynamic motions in sTF. In particular, the decrease in the Pro⁷⁹-Pro⁹² loop motions indicates that loop entropy has a role in the thermodynamics of the protein-protein interactions involved in allosteric control of VIIa activation.     

Trpm4 Gene Invalidation Leads to Cardiac Hypertrophy and Electrophysiological Alterations

Rationale

TRPM4 is a non-selective Ca²⁺-activated cation channel expressed in the heart, particularly in the atria or conduction tissue. Mutations in the Trpm4 gene were recently associated with several human conduction disorders such as Brugada syndrome. TRPM4 channel has also been implicated at the ventricular level, in inotropism or in arrhythmia genesis due to stresses such as ß-adrenergic stimulation, ischemia-reperfusion, and hypoxia re-oxygenation. However, the physiological role of the TRPM4 channel in the healthy heart remains unclear.

Objectives

We aimed to investigate the role of the TRPM4 channel on whole cardiac function with a Trpm4 gene knock-out mouse (Trpm4 ^-/-) model.

Methods and Results

Morpho-functional analysis revealed left ventricular (LV) eccentric hypertrophy in Trpm4 ^-/- mice, with an increase in both wall thickness and chamber size in the adult mouse (aged 32 weeks) when compared to Trpm4^+/+ littermate controls. Immunofluorescence on frozen heart cryosections and qPCR analysis showed no fibrosis or cellular hypertrophy. Instead, cardiomyocytes in Trpm4^-/- mice were smaller than Trpm4^+/+with a higher density. Immunofluorescent labeling for phospho-histone H3, a mitosis marker, showed that the number of mitotic myocytes was increased 3-fold in the Trpm4^-/-neonatal stage, suggesting hyperplasia. Adult Trpm4 ^-/- mice presented multilevel conduction blocks, as attested by PR and QRS lengthening in surface ECGs and confirmed by intracardiac exploration. Trpm4^-/-mice also exhibited Luciani-Wenckebach atrioventricular blocks, which were reduced following atropine infusion, suggesting paroxysmal parasympathetic overdrive. In addition, Trpm4 ^-/- mice exhibited shorter action potentials in atrial cells. This shortening was unrelated to modifications of the voltage-gated Ca²⁺ or K⁺ currents involved in the repolarizing phase.

Conclusions

TRPM4 has pleiotropic roles in the heart, including the regulation of conduction and cellular electrical activity which impact heart development.     

Urotensin II receptor predicts the clinical outcome of prostate cancer patients and is involved in the regulation of motility of prostate adenocarcinoma cells

Urotensin II (UT-II) is a potent vasoconstrictor peptide and its receptor (UTR) was correlated with human cortico-adrenal carcinoma proliferation. In this study, we have evaluated the correlation between UTR expression and prognosis of human prostate adenocarcinoma and the involvement of this receptor in the regulation of biological properties on both in vivo and in vitro models. UTR mRNA and protein, evaluated by real-time PCR and Western blotting, respectively, were expressed at high levels only in androgen-dependent LNCaP cells. In order to investigate UTR changes occurring in human prostate tumorigenesis, we have also evaluated the expression of UTR in vivo in 195 human prostate tissue samples. UTR was always expressed at low intensity in hyperplastic tissues and at high intensity in well-differentiated carcinomas (Gleason 2-3). Moreover, we have evaluated the effects of an antagonist of UTR, urantide on migration and invasion of LNCaP cells. Urantide induced a dose-dependent decrease of motility and invasion of LNCaP cells whose characteristic ameboid movement seems to be advantageous for their malignancy. These effects were paralleled by down-regulating the autophosphorylation of focal adhesion kinase and the integrin surface expression on LNCaP cells. The effects on cell motility and invasion were likely due to the inhibition of RhoA activity induced by both urantide and shRNA UTR. These data suggest that UTR can be considered a prognostic marker in human prostate adenocarcinoma patients.     

Frequency of Antibiotic-Associated Diarrhea and Related Complications in Pediatric Patients Who Underwent Hypospadias Repair: a Comparative Study Using Probiotics vs Placebo

Probiotics and Antimicrobial Proteins - This study aimed to evaluate the effectiveness of probiotics (Lactobacillus rhamnosus GG), as a preventive measure of antibiotic-associated diarrhea (AAD) in...     

Molecular analysis of gene expression in the developing pontocerebellar projection system

As an approach toward understanding the molecular mechanisms of neuronal differentiation, we utilized DNA microarrays to elucidate global patterns of gene expression during pontocerebellar development. Through this analysis, we identified groups of genes specific to neuronal precursor cells, associated with axon outgrowth, and regulated in response to contact with synaptic target cells. In the cerebellum, we identified a phase of granule cell differentiation that is independent of interactions with other cerebellar cell types. Analysis of pontine gene expression revealed that distinct programs of gene expression, correlated with axon outgrowth and synapse formation, can be decoupled and are likely influenced by different cells in the cerebellar target environment. Our approach provides insight into the genetic programs underlying the differentiation of specific cell types in the pontocerebellar projection system.     

Statistical evaluation of inter- and intra-laboratory variations of the Ames test, as related to the genetic stability of Salmonella tester strains

A statistical analysis was performed on the data resulting from an international collaborative study of the Ames test according to a standardized experimental protocol, which involved the comparative testing of 4NQO (4 doses), in 3 separate experiments for each of the 38 participating laboratories, by using a common reference (R) culture and in-house laboratory (L) cultures of 5 strains of S. typhimurium. Despite some toxicity phenomena recorded at the highest dose of 4NQO, the majority of the dose-response curves in individual laboratories were linear on a bi-log scale and their mean values fitted a linear regression framework. Scattering of data around mean values of laboratories was Gaussian-like even at the highest dose of 4NQO, toxic effects being expressed as a dose-related increase of variance. A weighted least-square analysis could therefore take into account toxic effects without resorting to a sophisticated non-linear model incompatible with log transformation. Various analytical approaches--e.g. the weighted estimates of linear regression parameters, a multifactor (laboratory, experiment, dose, culture of each strain) analysis of variance with all the possible interactions, the assessment of correlations in individual laboratories and of coefficients of variation for induced and spontaneous mutability--could detect some statistically significant differences between L and R cultures. However, at a critical evaluation on an individual basis, only few of these differences, without any peculiar involvement of given strains, were convincing in view of the existence of real phenomena of genetic drift. Therefore, on the whole, the genetic drift of Salmonella tester strains appears to lend a negligible contribution to the considerable inter- and intra-laboratory variability detected in this study. With a background variability between replications averaging 26%, a dose-related variability was evident both between experiments (28-54%) and between laboratories (44-127%).