Viscoelastic hybrid nanofluid flow over a vertical plate with sinusoidal surface temperature variations.

Natural convection of a viscoelastic hybrid nanofluid along a vertically heated plate with sinusoidal surface temperature variations is investigated. The current investigation explores the non-similar boundary layer flow patterns and heat transfer of second-grade viscoelastic flow of hybrid nanofluid. Effects of magnetic field and thermal radiation are considered. The governing dimensional equations are converted into a non-dimensional form taking suitable transformations. Resulting equations are solved with the aid of finite difference method. It is discovered that the momentum boundary layer lessens while the thermal boundary layer grows for higher radiation parameters, surface temperature parameters, Eckert numbers, magnetic field parameters and amount of nanoparticles. For larger Deborah numbers (De1), shear stress (τ) and heat transfer rate (q) accelerate, but momentum and thermal boundary decline near the leading edge of the vertical plate. However, the effects of Deborah number (De2) show opposite results. Increase in magnetic field parameters causes a reduction in shear stress. The higher volume fraction of nanoparticles (φ1, φ2) enhances q as it was expected. Moreover, τ and q were increased with larger surface temperature parameters and decrease with higher Eckert numbers. This is because higher surface temperature boost up the fluid temperature, but higher Eckert numbers admit the fluid to spread over the surface. An increase in the amplitude of surface temperature oscillation enhances the shear stress and heat transfer rate.

Broad-spectrum non-nucleoside inhibitors of human herpesviruses.

Herpesvirus infections cause considerable morbidity and mortality through lifelong recurrent cycles of lytic and latent infection in several tissues, including the human nervous system. Acyclovir (ACV) and its prodrug, the current antivirals of choice for herpes simplex virus (HSV) and, to some extent, varicella zoster virus (VZV) infections are nucleoside analogues that inhibit viral DNA replication. Rising viral resistance and the need for more effective second-line drugs have motivated searches for additional antiviral agents, particularly non-nucleoside based agents. We evaluated the antiviral activity of five compounds with predicted lysosomotropic activity using conventional and human induced pluripotent stem cell-derived neuronal (iPSC-neurons) cultures. Their potency and toxicity were compared with ACV and the lysosomotropic agents chloroquine and bafilomycin A1. Out of five compounds tested, micromolar concentrations of 30N12, 16F19, and 4F17 showed antiviral activity comparable to ACV (50µM) during lytic herpes simplex virus type 1 (HSV-1) infections, reduced viral DNA copy number, and reduced selected HSV-1 protein levels. These compounds also inhibited the reactivation of 'quiescent' HSV-1 infection established in iPSC-neurons, but did not inhibit viral entry into host cells. The same compounds had greater potency than ACV against lytic VZV infection; they also inhibited replication of human cytomegalovirus. The anti-herpetic effects of these non-nucleoside agents merit further evaluation in vivo.

A single element in the 3'UTR of the apical sodium-dependent bile acid transporter controls both stabilization and destabilization of mRNA.

mRNA stability appears to play a key role in the ontogenic regulation of the apical sodium-dependent bile acid transporter (ASBT). The RNA-binding proteins Hu antigen R (HuR) and tristetraprolin (TTP) stabilize and destabilize ASBT mRNA, respectively. Potential HuR-binding sites were assessed by sequence analysis in the context of prior in vitro functional analyses of the rat ASBT 3'UTR. Wild-type and mutant-binding sites were investigated by gel-shift analysis using IEC-6 cell extracts. The functional consequences of binding site mutations were assessed using two different hybrid reporter constructs linking the 3'UTR element to either a luciferase or a ß-globin coding mRNA sequence. A specific metastasis-associated gene 1 (MTA1) cis-element was identified in the ASBT 3'UTR that became associated with proteins in IEC-6 cell extracts and could be supershifted by anti-HuR or anti-TTP antibodies. Mutation of this cis-element abrogated the gel shift of IEC-6 proteins. Furthermore, hybrid constructs containing a mutant MTA1 element had reduced responses to modulation of HuR or TTP. For the first time, we have identified a single specific sequence element in the 3'UTR of the rat ASBT mRNA that mediates counter-regulatory changes in mRNA abundance in response to both HuR and TTP.

c-Fos mediates repression of the apical sodium-dependent bile acid transporter by fibroblast growth factor-19 in mice.

Fibroblast growth factor-19 (FGF-19), a bile acid-responsive enterokine, is secreted by the ileum and regulates a variety of metabolic processes. These studies examined the signal transduction pathways operant in FGF-19-mediated repression of the apical sodium-dependent bile acid transporter (ASBT). Responses to FGF-19 were assessed in Caco-2 and CT-26 cells and in mice where c-fos was conditionally silenced in the intestine by a cre-lox strategy. FGF-19 treatment of Caco-2 cells or wild-type mice led to a significant reduction in ASBT protein expression and enhanced phosphorylation of extracellular signaling kinase 1/2 (ERK1/2), c-Fos, and c-Jun. FGF-19 treatment of Caco-2 cells led to a reduction in activity of the human ASBT promoter and this repression could be blocked by treatment with a mitogen-activated protein kinase/ERK kinase (MEK1/2) inhibitor or by silencing jun kinase 1, jun kinase 2, c-fos, or c-jun. Site directed mutagenesis of a c-fos binding element in the ASBT promoter blocked FGF-19-mediated repression in luciferase reporter constructs. ASBT promoter activity was repressed by FGF-19 in CT-26 cells and this repression could be reduced by MEK1/2 inhibition or silencing c-fos. FGF-19-mediated repression of ASBT protein expression was abrogated in mice where c-fos was conditionally silenced in the intestine. In contrast, ASBT was repressed in the c-Fos expressing gallbladders of the same mice. The studies demonstrate that FGF-19 represses the expression of ASBT in the ileum and gallbladder via a signal transduction pathway involving MEK1/2, ERK1/2, JNK1, JNK2, and c-Fos.

Phospholipase D2 mediates signaling by ATPase class I type 8B membrane 1.

Functional defects in ATPase class I type 8B membrane 1 (ATP8B1 or familial intrahepatic cholestasis 1, FIC1) lead to cholestasis by mechanism(s) that are not fully understood. One proposed pathophysiology involves aberrant signaling to the bile acid sensor, the farnesoid X receptor (FXR), via protein kinase C ζ (PKCζ). The following cell line-based studies investigated whether phospholipase D2 may transduce a signal from FIC1 to FXR. PLD2 gain of function led to activation of the bile salt export pump (BSEP) promoter, a well-characterized FXR response. BSEP activation by PLD2 could be blocked by abrogating either PKCζ or FXR signaling. PLD2 loss of function led to a reduction in BSEP promoter activity. In addition, a variety of proteins that are activated by FXR, including BSEP, were reduced in HepG2 cells treated with PLD2 siRNA. Similar effects were observed in freshly isolated human hepatocytes. Activation of BSEP by FIC1 gain of function was blocked when PLD2 but not PLD1 was silenced. Overexpression of wild-type but not Byler mutant FIC1 led to an increase in membrane associated PLD activity. An intermediate level of activation of PLD activity was induced when a benign recurrent intrahepatic cholestasis FIC1 mutant construct was expressed. These studies show that FIC1 signals to FXR via a signaling pathway including PLD2 and PKCζ.

Protection of acetaminophen induced mitochondrial dysfunctions and hepatic necrosis via Akt-NF-kappaB pathway: role of a novel plant protein.

Oxidative stress is a major cause of drug induced hepatic diseases. The present study aims to investigate the antioxidative signaling mechanism of a protein isolated from the herb, Cajanus indicus against acetaminophen induced necrotic cell death. We found that incubation of hepatocytes with the protein prevented acetaminophen-induced loss in cell viability, reduction in glutathione level and enhancement of reactive oxygen species generation. Treatment of mice with the protein before administration of acetaminophen also reduced serum nitrite and TNF-alpha formation. Moreover, it counteracted acetaminophen-induced loss in mitochondrial membrane potential, loss in adenosine tri phosphate and rise in intracellular calcium. Investigating the cell signaling pathways, we found that the protein exerts its protective action via the activation of NF-kappaB and Akt and deactivation of STAT-1. Surprisingly, no role of ERK1/2 or STAT-3 was found in the protein-mediated protection of hepatocytes during acetaminophen exposure. Finally, we found that acetaminophen introduces necrosis as the primary phenomena of cell death and protein treatment decreased the necrotic process as evident from the DNA fragmentation and flow-cytometry studies. In addition, administration of the protein to mice before acetaminophen application showed fewer number of TUNEL positive cells. Combining, data suggest that the protein possesses cytoprotective activity against acetaminophen-induced oxidative cellular damage and prevents hepatocytes from necrotic death.

A protein from Cajanus indicus Spreng protects liver and kidney against mercuric chloride-induced oxidative stress.

Mercuric chloride (HgCl(2)) is a widespread environmental toxin that affects mainly liver and kidney. The present study has been carried out to investigate the protective action of a protein (the CI protein) isolated from the herb, Cajanus indicus Spreng against HgCl(2) induced renal and hepatic toxicities in mice. Intraperitoneal administration of HgCl(2) at a dose of 5 mg/kg body weight for 1 d significantly reduced the activities of antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). Moreover, it also depleted the glutathione to oxidized glutathione (GSH/GSSG) ratio. In addition, HgCl(2) increased the activities of serum marker enzymes (namely, glutamate pyruvate transaminase, GPT and alkaline phosphatase, ALP), creatinine, blood urea nitrogen and serum tumor necrosis factor alpha (TNF-alpha) level along with hepatic and renal lipid peroxidation. Besides, application of HgCl(2) to hepatocytes increased reactive oxygen species production and reduced the total antioxidant activity of the treated hepatocytes. Treatment with the CI protein intraperitoneally at a dose of 2 mg/kg body weight before or after HgCl(2) administration showed that it could scavenge free radicals in vitro and protect the alterations of the antioxidant molecules and the other parameters used in this particular study. Histological studies also revealed a milder lesion in kidney and liver samples of the CI protein treated mice compared to mice treated with HgCl(2) alone. Effects of a known antioxidant N-acetylcysteine have been used to compare its action to that of the CI protein.

Anti-oxidative effect of a protein from Cajanus indicus L against acetaminophen-induced hepato-nephro toxicity.

Overdoses of acetaminophen cause hepato-renal oxidative stress. The present study was undertaken to investigate the protective effect of a 43 kDa protein isolated from the herb Cajanus indicus, against acetaminophen-induced hepatic and renal toxicity. Male albino mice were treated with the protein for 4 days (intraperitoneally, 2 mg/kg body wt) prior or post to oral administration of acetaminophen (300 mg/kg body wt) for 2 days. Levels of different marker enzymes (namely, glutamate pyruvate transaminase and alkaline phosphatase), creatinine and blood urea nitrogen were measured in the experimental sera. Intracellular reactive oxygen species production and total antioxidant activity were also determined from acetaminophen and protein treated hepatocytes. Indices of different antioxidant enzymes (namely, superoxide dismutase, catalase, glutathione-S-transferase) as well as lipid peroxidation end-products and glutathione were determined in both liver and kidney homogenates. In addition, Cytochrome P450 activity was also measured from liver microsomes. Finally, histopathological studies were performed from liver sections of control, acetaminophen-treated and protein pre- and post-treated (along with acetaminophen) mice. Administration of acetaminophen increased all the serum markers and creatinine levels in mice sera along with the enhancement of hepatic and renal lipid peroxidation. Besides, application of acetaminophen to hepatocytes increased reactive oxygen species production and reduced the total antioxidant activity of the treated hepatocytes. It also reduced the levels of antioxidant enzymes and cellular reserves of glutathione in liver and kidney. In addition, acetaminophen enhanced the cytochrome P450 activity of liver microsomes. Treatment with the protein significantly reversed these changes to almost normal. Apart from these, histopathological changes also revealed the protective nature of the protein against acetaminophen induced necrotic damage of the liver tissues. Results suggest that the protein protects hepatic and renal tissues against oxidative damages and could be used as an effective protector against acetaminophen induced hepato-nephrotoxicity.

Purification and characterization of a 43 kD hepatoprotective protein from the herb Cajanus indicus L.

Cajanus indicus L, a herb, is popularly known for its hepatoprotective activity. Aqueous extract of the leaves of this plant contains hepatoprotective and hepatostimulatory molecule(s). Present study was aimed to isolate, purify and characterize the active principle(s) responsible for that activity. A hepatoprotective protein molecule has been purified to homogeneity (approximately 300 fold). Homogeneous preparation of the protein was achieved by homogenization, (NH(4))(2)SO(4) precipitation, ion-exchange chromatography, gel filtration and high performance liquid chromatography. The protein purified is composed of a single polypeptide chain having an apparent molecular mass of 43 kD as determined by SDS-PAGE and gel filtration through sephadex G-75 column. The isoelectric point of the protein determined was 4.8. Loss of biological activity after heat and protease treatment confirmed that the active molecule is a protein. Peptide fragments of the protein generated by trypsin cleavage were subjected to MALDI-TOF as well as LC-MS analyses and among the various fragments, four were very prominent and used for the determination of the amino acid sequence of the hepatoprotective protein. While one of the peptide fragment revealed strong sequence homology with plastocyanin, another fragment showed some similarity with a tomato protein present in the NCBI non-redundant database. The third peptide, on the other hand, is unique as it did not show any sequence homology with any known protein in the database. The protein showed maximum hepatoprotective activity when administered at a dose of 2 mg/kg body weight for five days after CCl(4 )administration. Histopathological studies also supported the hepatoprotective nature of the protein. Along with its curative property, the protein also possesses preventive role against a number of toxin induced hepatic damages.

A 43-kDa protein from the leaves of the herb Cajanus indicus L. modulates chloroform induced hepatotoxicity in vitro.

A 43-kDa protein isolated from the leaves of the herb Cajanus indicus L. has been shown to possess a protective role against drug- and toxin- induced hepatotoxicity both in vivo and in vitro. The current study was conducted to evaluate its protective action against chloroform (CHCl3)-induced cytotoxicity in hepatocytes. Cellular viability and biochemical parameters such as glutamate pyruvate transaminase (GPT) and lactate dehydrogenase (LDH) release from the cells were measured. In addition, the antioxidant effect of the protein was investigated from the DPPH radical scavenging assay and by determining the levels of the antioxidant enzyme catalase (CAT), cellular reserves of reduced glutathione (GSH), and lipid peroxidation end products (measured as TBARS). Treatment of the cells with CHCl3 decreased cellular viability and increased GPT and LDH. Cells treated with the protein before and immediately after CHCl3 application showed a marked improvement in their viability and reduced leakage of GPT and LDH. The levels of CAT and GSH, which were diminished in cells treated with CHCl3, were restored by protein treatment. CHCl3 induced enhancement of lipid peroxidation in hepatocytes was significantly reduced by protein treatment. Results of the DPPH assay with the protein showed its radical scavenging activity. This data suggests that the protein possesses protective activity against CHCl3-induced cytotoxicity in hepatocytes and protects against CHCl3-induced hepatic damage.

Protective effect of a 43 kD protein from the leaves of the herb, Cajanus indicus L on chloroform induced hepatic-disorder.

Cajanus indicus is a herb with medicinal properties and is traditionally used to treat various forms of liver disorders. Present study aimed to evaluate the effect of a 43 kD protein isolated from the leaves of this herb against chloroform induced hepatotoxicity. Male albino mice were intraperitoneally treated with 2 mg/kg body weight of the protein for 5 days followed by oral application of chloroform (0.75 ml/kg body weight) for 2 days. Different biochemical parameters related to physiology and pathophysiology of liver, such as, serum glutamate pyruvate transaminase and alkaline phosphatase were determined in the murine sera under various experimental conditions. Direct antioxidant role of the protein was also determined from its reaction with Diphenyl picryl hydroxyl radical, superoxide radical and hydrogen peroxide. To find out the mode of action of this protein against chloroform induced liver damage, levels of antioxidant enzymes catalase, superoxide dismutase and glutathione-S-transferase were measured from liver homogenates. Peroxidation of membrane lipids both in vivo and in vitro were also measured as malonaldialdehyde. Finally, histopathological analyses were done from liver sections of control, toxin treated and protein pre- and post-treated (along with the toxin) mice. Levels of serum glutamate pyruvate transaminase and alkaline phosphatase, which showed an elevation in chloroform induced hepatic damage, were brought down near to the normal levels with the protein pretreatment. On the contrary, the levels of antioxidant enzymes such as catalase, superoxide dismutase and glutathione-S-transferase that had gone down in mice orally fed with chloroform were significantly elevated in protein pretreated ones. Besides, chloroform induced lipid peroxidation was effectively reduced by protein treatment both in vivo and in vitro. In cell free system the protein effectively quenched diphenyl picryl hydroxyl radical and superoxide radical, though it could not catalyse the breakdown of hydrogen peroxide. Post treatment with the protein for 3 days after 2 days of chloroform administration showed similar results. Histopathological studies indicated that chloroform induced extensive tissue damage was less severe in the mice livers treated with the 43 kD protein prior and post to the toxin administration. Results from all these data suggest that the protein possesses both preventive and curative role against chloroform induced hepatotoxicity and probably acts by an anti-oxidative defense mechanism.

Preventive and curative role of a 43kD protein from the leaves of the herb Cajanus indicus L on thioacetamide-induced hepatotoxicity in vivo.

An approximately 43kD protein has been isolated and purified from the herb Cajanus indicus L and believed to be the most active principle for its hepatoprotective action. In this study, experiments have been performed to evaluate the effectiveness of that protein for the preventive and curative action against thioacetamide-induced toxicity in vivo using a murine model. Mice were treated with the protein intraperitoneally at a dose of 2mg/kg body weight for 2 and 6 days before and separately 1-5 days after thioacetamide administration to evaluate its preventive and curative role, respectively. Thioacetamide was administered once at a dose of 150mg/kg body weight and after 48h of its application, the animals were sacrificed. Levels of various markers related to physiological and pathological conditions of the liver, e.g., glutamate pyruvate transaminase (GPT), alkaline phosphatase (ALP), etc. were determined in the murine sera under different experimental conditions. In addition, antioxidant enzymes glutathione S-transferase (GST), superoxide dismutase (SOD) and catalase (CAT) as well as thiobarbituric acid reactive substances (TBARS), were measured from the liver homogenates. The antioxidant property of the protein was compared with the potent antioxidant, vitamin E (used as a positive control). The active principle effectively reduced the elevated GPT and ALP levels in serum and lipid peroxidation in the liver tissue. The reduced levels of SOD, CAT and GST by thioacetamide were again brought back to almost normal levels upon pre- and post-treatment with the protein. Histopathological changes in the liver of TAA control and protein-treated groups also prove that the protein possesses hepatoprotective activity. The protein acts dose-dependently and maximum hepatoprotectivity was obtained when administered at a dose of 2mg/kg body weight. Data suggest that the active principle plays an important preventive and curative role against thioacetamide-induced hepatotoxicity.