In vitro and in vivo inhibitory actions of morin on rat brain phosphatidylinositolphosphate kinase activity

Phosphatidylinositol-4,5-bisphosphate occupies a central role in signal transduction and in cellular transformation. Phosphatidylinositol-4,5-bisphosphate is produced by the enzymatic phosphorylation of phosphatidylinositol-4-phosphate by phosphatidylinositolphosphate kinase (EC 2.7.1.68). Inhibition of this enzyme might conceivably lowers the cellular pool of phosphatidylinositol-4,5-bisphosphate, thus constituting a feasible control point in regulating signal transduction and cellular transformation. Morin, a plant flavonoid, was demonstrated to exhibit in vitro inhibitory action on phosphatidylinositolphosphate kinase extracted from rat brain. This inhibition of enzymatic activity was found to be dose-dependent, with an IC50 value of approximately 10 microM morin. Lineweaver-Burk transformation of the inhibition data indicates that inhibition was competitive with respect to ATP. The Ki was calculated to be 5.15 x 10(-6) M. Inhibition was uncompetitive with respect to phosphatidylinositol-4-phosphate. The Ki was determined to be 0.94 x 10(-5) M. Administration of morin to rats led to a decrease in phosphatidylinositolphosphate kinase activity in brain extracts. This in vivo action of morin was found to be dose-dependent and time-dependent. These effects of morin on rat brain phosphatidylinositolphosphate kinase activity are discussed in relation to the other reported biological actions of this flavonoid.     

Captopril modifies gene expression in hypertrophied and failing hearts of aged spontaneously hypertensive rats

The spontaneously hypertensive rat (SHR) exhibits a transition from stable compensated left ventricular (LV) hypertrophy to heart failure (HF) at a mean age of 21 months that is characterized by a decrease in alpha-myosin heavy chain (alpha-MHC) gene expression and increases in the expression of the atrial natriuretic factor (ANF), pro-alpha1(III) collagen, and transforming growth factor beta1 (TGF-beta1) genes. We tested the hypotheses that angiotensin-converting enzyme inhibition (ACEI) in SHR would prevent and reverse HF-associated changes in gene expression when administered prior to and after the onset of HF, respectively. We also investigated the effect of ACEI on circulating and cardiac components of the renin-angiotensin system. ACEI (captopril 2 g/L in the drinking water) was initiated at 12, 18, and 21 months of age in SHR without HF and in SHR with HF. Results were compared with those of age-matched normotensive Wistar-Kyoto (WKY) rats, and to untreated SHR with and without evidence of HF. ACEI initiated prior to failure prevented the changes in alpha-MHC, ANF, pro-alpha1(III) collagen, and TGF-beta1 gene expression that are associated with the transition to HF. ACEI initiated after the onset of HF lowered levels of TGF-beta1 mRNA by 50% (P<.05) and elevated levels of alpha-MHC mRNA two- to threefold (P<.05). Circulating levels of renin and angiotensin I were elevated four- to sixfold by ACEI, but surprisingly, plasma levels of angiotensin II were not reduced. ACEI increased LV renin mRNA levels in WKY and SHR by two- to threefold but did not influence LV levels of angiotensinogen mRNA. The results suggest that the anti-HF benefits of ACEI in SHR may be mediated, at least in part, by effects on the expression of specific genes, including those encoding alpha-MHC, ANF, TGF-beta1, pro-alpha1(III) collagen, and renin-angiotensin system components.     

Idiopathic thrombocytopenic purpura in a liver transplant recipient with previous primary biliary cirrhosis

The loss of immunotolerance has been implicated in the pathogenesis of both primary biliary cirrhosis (PBC) and idiopathic, immune-mediated thrombocytopenic purpura (ITP). An association between these two autoimmune diseases has been well described. We describe a 41-year-old woman in whom ITP developed 457 days after liver transplantation for PBC while receiving immunosuppressive medications sufficient to maintain allograft function. Our case report, the first to describe post-transplant ITP in association with PBC, demonstrates the persistence of the underlying immune dysregulation of PBC after transplantation. The practice of decreasing the dosage of immunosuppressive medication to maintenance levels after transplantation may unmask the effects of this defect in immunotolerance.     

Mechanisms underlying the chronotropic effect of angiotensin II on cultured neurons from rat hypothalamus and brain stem

The chronotropic effect of angiotensin II (Ang II) was studied in cultured neurons from rat hypothalamus and brain stem with the use of the patch-clamp technique. Ang II (100 nM) increased the neuronal spontaneous firing rate from 0.8 +/- 0.3 (SE) Hz in control to 1.3 +/- 0.4 Hz (n = 7, P < 0.05). The amplitude of threshold stimulation was decreased by Ang II (100 nM) from 82 +/- 4 pA to 62 +/- 5 pA (n = 4, P < 0.05). These actions of Ang II were reversed by the angiotensin type 1 (AT1) receptor antagonist losartan (1 microM). In the presence of tetrodotoxin, Ang II (100 nM) significantly increased the frequency and the amplitude of the Cd2+-sensitive subthreshold activity of the cultured neurons. Ang II also stimulated the subthreshold early afterdepolarizations (EADs) to become fully developed action potentials. Similar to the action of Ang II, the protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA, 100 nM) increased the firing rate from 0.76 +/- 0.3 Hz to 2.3 +/- 0.5 Hz (n = 6, P < 0.05) and increased the neuronal subthreshold activity. After neurons were intracellularly dialyzed with PKC inhibitory peptide (PKCIP, 5 microM), PMA alone, Ang II alone, or PMA plus Ang II no longer increased the action potential firing initiated from the resting membrane potential level. However, superfusion of PMA plus Ang II or Ang II alone increased the number of EADs that reached threshold and produced action potentials even in the presence of PKCIP (5 microM, n = 4). The actions of Ang II could also be mimicked by depolarizing pulse and K+ channel blockers (tetraethylammonium chloride or 4-aminopyridine). These results indicate that Ang II by activation of AT1 receptors increases neuronal excitability and firing frequency, and that this may involve both PKC dependent and -independent mechanisms.     

Pleiotropic,Unique and Shared Responses Elicited by IL-6 Family Cytokines in Human Vascular Endothelial Cells

Vascular endothelial cells express glycoprotein 130 (gp130), which is utilized as a signaling receptor by cytokines in the interleukin-6 (IL-6) family. Several IL-6 family cytokines can be found in the circulatory system during physiological or pathological conditions, and may influence endothelial function and response. This study evaluated and compared the cellular and molecular responses induced by IL-6 family cytokines in human endothelial cells. A proteomic analysis showed that IL-6 family cytokines induce the release of a range of proteins from endothelial cells, such as C-C motif chemokine ligand 23, hepatocyte growth factor, and IL-6. Pathway analysis indicated that gp130-signaling in endothelial cells regulates several functions related to angiogenesis and immune cell recruitment. The present investigation also disclosed differences and similarities between different IL-6 family cytokines in their ability to induce protein release and regulate gene expression and intracellular signaling, in regards to which oncostatin M showed the most pronounced effect. Further, this study showed that soluble gp130 preferentially blocks trans-signaling-induced responses, but does not affect responses induced by classic signaling. In conclusion, IL-6 family cytokines induce both specific and overlapping molecular responses in endothelial cells, and regulate genes and proteins involved in angiogenesis and immune cell recruitment.     

Predicting and rationalizing the effect of surface charge distribution and orientation on nano-wire based FET bio-sensors

A single charge screening model of surface charge sensors in liquids (De Vico et al., Nanoscale, 2011, 3, 706-717) is extended to multiple charges to model the effect of the charge distributions of analyte proteins on FET sensor response. With this model we show that counter-intuitive signal changes (e.g. a positive signal change due to a net positive protein binding to a p-type conductor) can occur for certain combinations of charge distributions and Debye lengths. The new method is applied to interpret published experimental data on Streptavidin (Ishikawa et al., ACS Nano, 2009, 3, 3969-3976) and Nucleocapsid protein (Ishikawa et al., ACS Nano, 2009, 3, 1219-1224).     

Trans isomeric octadecenoic acids are related inversely to arachidonic acid and DHA and positively related to mead acid in umbilical vessel wall lipids

Long-chain PUFA play an important role in early human neurodevelopment. Significant inverse correlations were reported between values of trans isomeric and long-chain PUFA in plasma lipids of preterm infants and children aged 1–15 yr as well as in venous cord blood lipids of full-term infants. Here we report FA compositional data of cord blood vessel wall lipids in 308 healthy, full-term infants (gestational age: 39.7±1.2 wk, birth weight: 3528±429 g, mean±SD). The median (interquartile range) of the sum of 18-carbon trans FA was 0.22 (0.13)% w/w in umbilical artery and 0.16 (0.10)% w/w in umbilical vein lipids. Nonparametric correlation analysis showed significant inverse correlations between the sum of 18-carbon trans FA and both arachidonic acid and DHA in artery (r=−0.38, P<0.01, and r=−0.20, P<0.01) and vein (r=−0.36, P<0.01, and −0.17, P<0.01) wall lipids. In addition, the sum of 18-carbon trans FA was significantly positively correlated to Mead acid, a general indicator of EFA deficiency, in both artery (r=+0.35, P<0.01) and vein (r=+0.31, P<0.01) wall lipids. The present results obtained in a large group of full-term infants suggest that maternal trans FA intake is inversely associated with long-chain PUFA status of the infant at birth.     

Characterization of Biomimetic Cofactors According to Stability,Redox Potentials,and Enzymatic Conversion by NADH Oxidase from Lactobacillus pentosus

Oxidoreductases are attractive biocatalysts that convert achiral substrates into products of higher value, but they are also for the most part dependent on nicotinamide cofactors. Recently, biomimetic nicotinamide derivatives have received attention as less costly alternatives to natural cofactors. However, recycling of biomimetics is still challenging because there are only limited opportunities. Here, we have characterized various biomimetic cofactors with regard to stability and redox potentials to find the best alternative to natural cofactors. Further, the cofactor spectrum of NADH oxidase from Lactobacillus pentosus (LpNox) could be expanded, and the enzymatic activity was also compared to activities with different small‐molecule catalysts. As a result, we succeeded in identifying several strategies for regeneration of oxidized biomimetics.     

MECHANISM OF DENDRITE FORMATION FROM A STREAM OF SUBMICRON AEROSOL IN THE PRESENCE OF EXTERNAL ELECTRIC FIELD

In the present work we extend the model of dendrite formation to the case of submicron unipolar charged particles, where the main transport mechanism in convective Brownian diffusion and electrical effects due to the presence of charges on the particles and electric field around cylindrical collector.

We present solutions for the case of slip flow around the fiber and free molecular flow around particles.